Home » Articles posted by RaceRealist (Page 41)
Author Archives: RaceRealist
Muscular Strength By Gender and Race
2000 words
It’s a known fact that men are stronger, but how much stronger are we really than women? Strength does vary by race as I have covered here extensively. However, I took another look at the only paper that I can find in the literature on black/white strength on the bench press and found one more data point that lends credence to my theory on racial differences in strength.
Strength and gender
Men are stronger than women. No one (sane) denies this. There are evolutionary reasons for this, main reason being, women selected us for higher levels of testosterone, along with differences in somatype. Now, what is not known by the general public is just how much stronger the average man is compared to the average woman.
Miller et al (2008) studied the fiber type and area and strength of the biceps brachii and vastus lateralis in 8 men and 8 women. They were told to do two voluntary tests of strength, using elbow flexion (think biceps curl) and knee extension. (Note: I am assuming they are exercises similar to biceps curls and knee extension, as the authors write that they had custom-made equipment from Global Gym.) They also measured motor unit size, number, and activation during both movements.
The women had 45 percent smaller muscle cross-section area (CSA) in the brachii, 41 percent in the total elbow flexor, 30 percent in the vastus laterus, and 25 percent smaller knee extensors. The last point makes sense, since women have stronger lower bodies compared to their upper bodies (as you can see).
Men were significantly stronger in both upper and lower body strength. In the knee extension, women was 62 and 59 percent of male 1RM and maximal voluntary isometric contraction (MVC) respectively. As for elbow strength, women were 52 percent as strong as men in both 1RM and MVC. Overall, women were 70 and 80 percent as strong as men in the arms and the legs. This is attributed to either men’s bigger fibers or men putting themselves into more physical situations to have bigger fibers to be stronger (…a biological explanation makes more sense). However, no statistical difference between muscle fibers was found between gender, lending credence to the hypothesis that men’s larger fibers are the cause for greater overall upper-body strength.
The cause for less upper-body strength in women is due the distribution of women’s lean tissue being smaller. Women, as can be seen in the study, are stronger in terms of lower limb strength and get substantially weaker when upper-body strength is looked at.
Other studies have shown this stark difference between male and female strength. Men have, on average, 61 percent more total muscle mass than women, 75 percent more arm muscle mass, which translates approximately into a 90 percent greater upper body strength in men. 99.9 percent of females fall below the male mean, meaning that sex accounts for 70 percent of human variation in muscle mass and upper-body strength in humans (Lassek and Gaulin, 2009). Women select men for increased muscular size, which means increased testosterone, but this is hard to maintain so it gets naturally selected against. There is, obviously, a limit to muscle size and how many kcal you can intake and partition enough kcal to your growing muscles. However, women are more attracted to a muscular, mesomorphic phenotype (Dixson et al, 2009) so selection will occur by women for men to have a larger body type due to higher levels of testosterone.
Strength and race
The only study I know of comparing blacks and whites on a big three lift (bench pressing) is by Boyce et al (2014). They followed a sample of 13 white female officers, 17 black female officers, 41 black male officers and 238 white male officers for 12.5 years, assessing bench pressing strength at the beginning and the end of the study. The average age of the sample was 25.1 for the 41 black males and 24.5 for the 237 white males. The average age for the black women was 24.9 and the average for white women was 23.9. This is a longitudinal study, and the methodology is alright, but I see a few holes.
An untrained eye looking at the tables in the study would automatically think that blacks are stronger than whites at the end of the study. At the initial recruitment, the black mean weight was 187 pounds and they benched 210 pounds. They benched 1.2 times their body weight. Whites weighed 180 pounds and benched 185 pounds. They benched 1.02 times their body weight. Black women weighed 130 pounds at initial recruitment and benched 85 pounds, benching .654 times their body weight. White women weighed 127 pounds at initial recruitment and bench 82 pounds, benching .646 times their body weight. Right off the bat, you can see that the difference between black and white women is not significant, but the difference between blacks and whites is.
At the follow-up, the black sample weighed 224 pounds and benched 240 pounds while the whites weighed 205 pounds benching 215 pounds. Looking at this in terms of strength relative to body weight, we see that black males benched 1.07 times their body weight while whites benched 1.04 times their body weight. A very slight difference favoring black males. However, there were more than 5 times the amount of whites in comparison to blacks (41 compared to 238), so I can’t help but wonder if the smaller black sample compared to the white sample may have anything to do with it.
Black women weighed 150 pounds at the follow-up, benching 99 pounds while white women weighed 140 pounds benching 90 pounds. So black women benched .66 times their body weight while white women benched .642 times their body weight.
Another thing we have to look at is black body weight compared to bench press decreased in the 12 years while white body weight compared to bench press was diverging with the black bench press compared to body weight.
Furthermore, this study is anomalous as the both cohorts gained strength into their late 30s (testosterone begins to decline at a rate of 1-2 percent per year at age 25). It is well known in the literature that strength begins to decrease at right around 25 years of age (Keller and Englehardt, 2014).
Another pitfall is that, as they rightly point out, they used skin caliper measuring on the black cohort. It has been argued in the literature that blacks should have a different BMI scale due to differing levels of fat-free body mass (Vickery et al, 1988). Remember that black American men with more African ancestry are less likely to be obese, which is due to levels of fat-free body mass. Since fat-free mass is most likely skewed, I shouldn’t even look at the study. I do believe that black Americans should have their own BMI scale; they’re physiologically different enough from whites—though the differences are small—they lead to important medical outcomes. This is why race most definitely should be implemented into medical research. The authors rightly state that when further research is pursued the DXA scan should be used to assess fat-free body mass.
Unfortunately, the authors did not have access to the heights of the cohort due to an ongoing court case on the department for discrimination based on height. So, unfortunately, this is the only anthropometric value that could not be assessed and is an extremely important variable. Height can be used to infer somatype. Somatype can then be used to infer limb length. Longer limbs increase the ROM, in turn, decreaseing strength. The missing variable of height is a key factor in this study.
Finally, and perhaps most importantly, they assessed the strength of the cohort on a Smith Machine Bench Press.
- The Smith Machine is set on a fixed range of motion; not all people have the same ROM, so assessing strength on a smith machine makes no sense.
- To get into position for the Smith Machine, since the bar path is the same, you need to get in pretty much the same position as everyone else. I don’t need to explain the anatomical reasons why this is a problem in regards to testing a 1RM.
- An Olympic bar weighs 45 pounds, but numerous Smith Machines decreases the weight by 10-20 pounds.
- Since the individual is not able to stabilize the bar due to the machine, the chest, triceps, and biceps are less activated during the Smith Machine lift (Saeterbakken et al, 2011)
Due to all of these things wrong with the study, especially the Smith Machine bench press, it’s hard to actually gauge the true strength of the cohort. Depending on the brand, Smith Machines can decrease the load by 10-30 pounds. Combined with the unnatural, straight-line bar path of the movement, it’s not ideal for a true strength test.
Conclusion
Gender differences in strength have a biological basis (obviously) and are why women shouldn’t be able to serve in the military and transgendered people shouldn’t be able to compete with ‘the gender they feel that they are’ (coming in the future).
The more interesting topic is the one on racial differences in strength. The untrained eye may read that paper and walk away assuming that the average black person is somehow stronger than the average white person. However, this study is anomalous since the cohort gained strength into their 30s when the literature shows otherwise. The biggest problem with the study is the Smith Machine bench press. It is not a natural movement and decreases muscle activation in key areas of the chest and triceps which aid in power while doing a regular bench press. Due to this, and the other problems I pointed out, I can’t accept this study.
Of course, height not being noted is not the fault of the researchers, but more questions would be answered if we knew the heights of the officers—which is an extremely critical variable. White males also gained more lean mass over the course of the study compared to blacks—47 percent and 44 percent respectively—which, as I pointed out, is anomalous.
There is more to HBD than IQ differences. I contend that somatype differences between the races are much more interesting. I will be writing about that more in the future.
Furthermore, for anyone with any basic physiology and anatomy knowledge, they’d know that different leverages affect strength. The races differ in somatype on average and thusly have different leverages. This is one out of many reasons why there are racial differences in strength and elite sports. Leverages and muscle fiber typing.
My points on racial differences in strength still hold; the anthropmetric data backs me up, elite sporting events back me up. My theory as a whole to racial differences in sports is sound, and this study does nothing to make me think twice about it. There are way too many confounds for me to even take it seriously when reevaluating my views on racial differences in strength. This study was garbage to assess absolutely strength due to the numerous things wrong with it. I await a more robust study with actual strength exercises, not one done on an assisted machine.
References
Boyce, R. W., Willett, T. K., Jones, G. R., & Boone, E. L. (2014). Racial Comparisons in Police Officer Bench Press Strength over 12.5 Years. Int J Exerc Sci 7 (2), 140-151.
Dixson, B. J., Dixson, A. F., Bishop, P. J., & Parish, A. (2009). Human Physique and Sexual Attractiveness in Men and Women: A New Zealand–U.S. Comparative Study. Archives of Sexual Behavior,39(3), 798-806. doi:10.1007/s10508-008-9441-y
Keller K, Engelhardt M. Strength and muscle mass loss with aging process. Age and strength loss. MLTJ. 2013;3(4):346–350.
Lassek, W. D., & Gaulin, S. J. (2009). Costs and benefits of fat-free muscle mass in men: relationship to mating success, dietary requirements, and native immunity. Evolution and Human Behavior,30(5), 322-328. doi:10.1016/j.evolhumbehav.2009.04.002
Miller, A. E., Macdougall, J. D., Tarnopolsky, M. A., & Sale, D. G. (1993). Gender differences in strength and muscle fiber characteristics. European Journal of Applied Physiology and Occupational Physiology,66(3), 254-262. doi:10.1007/bf00235103
Saeterbakken, A. H., Tillaar, R. V., & Fimland, M. S. (2011). A comparison of muscle activity and 1-RM strength of three chest-press exercises with different stability requirements. Journal of Sports Sciences,29(5), 533-538. doi:10.1080/02640414.2010.543916
Vickery SR, Cureton KJ, Collins MA. Prediction of body density from skinfolds in black and white young men. Hum Biol 1988;60:135–49.
Brain Size Increased for Expertise Capacity, not IQ
2000 words
One of the HBD’s supposed biggest findings is that IQ increases as a function of distance from the equator. The theory holds that those groups who experienced colder winters were selected for levels of higher g and they passed on their high IQ genes. Cold winter theory is supposed to explain why some races have higher levels of achievement and IQ than others. However, after a conversation with PumpkinPerson about cold winter theory and tool use, something clicked in my head: the real reason for the increase in brain size in peoples further from the equator wasn’t for IQ, but expertise capacity. I will go through the reasons how and why our brain size increased for the capacity for expertise and not IQ and hopefully put the cold winter theory to rest for good.
Tool complexity/use and brain size
PumpkinPerson is one of the biggest champions of the cold winter theory, writing: “I don’t even understand how one can believe in racially genetic differences in IQ without also believing that cold winters select for higher intelligence because of the survival challenges of keeping warm, building shelter, and hunting large game.” He wrongly assumes that climate theories are the only explanation for racial gaps in intelligence when other theories (such as differing types of sexual selection) could explain the gap just as well. However, since Rushton and Lynn have pushed this theory for 30+ years, it’s still engrained in the minds of some people. It is hard to change your views in the face of contrary data, but for those of my readers who are proponents of cold winters increasing IQ, I hope tonight I can sway you into believing that brain size increased as a function of climate and tool-making, not for IQ.
In his article he cites Richard Lynn (2006: 148), saying:
… hunter-gatherer peoples in tropical and subtropical latitudes such as the Amazon basin and New Guinea typically have between 10 and 20 different tools, whereas those in the colder northern latitudes of Siberia, Alaska, and Greenland have between 25 and 60 different tools. In addition, peoples in cold northern environments make more complex tools, involving the assembly of components, such as hafting a sharp piece of stone or bone onto the end of a spear and fixing a stone axe head onto a timber shaft.
I, of course, don’t doubt that peoples in cold northern environments need more (and complex) tools compared to those in tropical climes. But I look at it from a different point of view.
This is based on the research of Terrence (1983) and his study on time budgeting and hunter-gathering technology. The data does show that the number of tools correlates to latitude, but he leaves out that it also correlates with mobile and immobile and diet. That’s a pretty big factor. Of course, the type of animals around and what you need to do to kill/extract the meat involves a certain type of complex tool. In northern environments, a few more tools are needed to survive, so what? That doesn’t really mean anything. The whole brain-size/IQ latitude cold winter theory can be explained in another way.
Tool use increased our brain size throughout our evolutionary history, so with Arctic peoples living in cold climes where having a bigger brain is advantageous, they already had more neural columns for expertise capacity. The construction of complex tools increased brain size along with the colder climate. If tool use can explain part of the increase in our brain size over 3 million years, why can’t it partly explain why Arctic peoples—who use more (and complex) tools—larger brains over those further from the Arctic? Because brain size increased for expertise capacity, not IQ. Since they had bigger brains they were able to master the creation of complex tools, which further increased their brain size along with colder climates. Those who could make better tools could pass their genes, selecting for bigger brains.
Brain size increased for expertise capacity, not IQ
Table 3.1 in Torrence (1983) makes reference to technounits, a way to gauge the complexity of a particular item (Collard et al, 2011). Those in northerly climes do have tools with higher technounits, however, that’s showing that what is needed to construct the tools is a high capacity for expertise.
Skoyles (1999) posits that brain size increased for expertise capacity, not IQ. Bigger brains cause extreme complications during birth, calling for Caesarian sections (which is driving the evolution of bigger heads), so selection for bigger brains must have been advantageous in another way. Skoyles cites studies showing that microcephalics have brains in the average range of Erectus while having IQs in the normal/above average range. This implies that Erectus could have had IQs in our range, and that selection for bigger heads was caused by something else—the need for expertise.
Even then, the correlation between brain size and IQ cannot be invoked here. A .33-.4 correlation between brain size and IQ still leaves a lot of room for people to have brain sizes in the range of Erectus and still have above average IQs. Assuming a correlation of .51, that leaves 74 percent of the brain size/IQ correlation unexplained. This leaves a lot of room for other explanations for the remaining variance.
So if you think of the implications of Skoyles’ (1999) paper in regards to human races and the quote provided from Lynn (2006), you can look at it as Arctic peoples needed to be able to learn how to make complex tools which required a certain amount of expertise. Acquiring certain types of expertise does lead to certain local changes in the brain due to environmental demands, for instance in racecar drivers (Bernardi et al, 2013) and in taxi drivers in London who were “on The Knowledge” (Maguire et al, 2000). Tool use did cause increases in our brain size in our ancestral past, so the fact that Arctic peoples have bigger brains but lower IQs is explained by brain size being selected for expertise (their expertise to make their numerous tools) and cold climates but cold temperatures do NOT explain intelligence differences between the races.
Expertise
Indeed, there is evidence that ‘chunks’ form in the brain due to certain types of expertise (Gobet and Simon, 1998). In their study, Gobet and Simon showed that Chess masters used significantly more chunks, extending the chunking theory ” to take account of the evidence for large retrieval structures (templates) in long-term memory.” This study is direct evidence for Skoyles’ contention on “informational chunks (Skoyles, 1999) lending credence to the claim that people who master something have more information stored in their ‘chunks’.
Furthermore, high and low skill employees organize their conceptual knowledge about a problem differently (Lamberti and Newsome, 1989). Low-skilled workers performed much faster on the tasks that needed concrete information organization whereas high-skilled workers were better on the more abstract concepts. Overall, both high- and low-skilled workers processed the same information differently. This study has nothing to do with IQ itself, just how high- and low-skilled workers process information differently (which may come down to ‘chunks’ in the brain).
Chase and Simon (1973) show that the amount of information extracted during a memory and perception task is directly related to the amount of time the individual has played chess. They state that chess skill is “reflected in the speed with which chunks are perceived in the perception task and the size of the chunks in the memory task.” Of course, you can’t just throw anyone into a chess game who has never played before—IQ be damned—and expect them to do well. You need to hone your strategy and skill over time by noticing all types of moves, thinking ahead and guessing what your opponent will do ahead of time. This all takes time playing the game, and since people who have played longer can more easily tap into the ‘chunks’, this shows that chess skill is largely a function of time spend playing (note: IQ is still important, of course. Just, practice makes perfect and one with practice and a low IQ will beat someone with no/little practice and a high IQ).
Expertise does, indeed, take deliberate practice. Practice DOES make perfect.
Conclusion
Our brains increased evolutionarily speaking as to acquire more expertise. Bigger brains (and therefore bigger heads) cause problems with childbirth and so natural selection must have selected bigger brains since they increase expertise capacity. The fact that there are numerous people in the world with Erectus-sized brains and IQs in the normal/above average range lends credence to the claim. Erectus could have possibly had intelligence level near our own. But what really needs to be thought about here is this: It just so happens that the brain size increase corresponds with the beginnings of our modern gait and pelvis (Lieberman et al, 2006). The beginnings of cultural acquisition and transference began around that time (Herculano-Houzel and Kaas, 2011) and so our brain size would have increased due to cooking allowing us to have the energy for a bigger brain with more neurons.
Of course Erectus would need to become an expert with the new-found technology he acquired. Over time, the more ‘expert’ Erectus would have passed their genes on, both for increased brain size and expertise, and the hominin brain size then increased.
Looking at racial differences in brain size while thinking about how expertise capacity increases brain size and thinking about tool use/complexity of Arctic peoples is an alternate (and in my opinion) better theory of explaining racial differences in brain size. I obviously don’t believe that brain size differences cause IQ differences, the brain size differences are a function of climate and tool use/complexity. To make complex tools you need a sort of ‘expertness’, which, as Skoyles argues, causes brain size to increase. This explains the so-called anomalous Inuits with a brain size equal to that of East Asians but with an IQ in the low 90s.
Put simply, complex tools+cold winters+ cooked food=big brains. Cold climates DO NOT by themselves CAUSE higher levels of g. It’s just a correlation, it does not mean that it is causal. Big brains retain heat better in the cold whereas smaller heads cool better. That’s the reason for racial brain size differences, but climate and brain size in and of themselves do not CAUSE racial differences in IQ.
I now believe that sexual selection is a cause for racial differences in IQ, but that’s for another day.
References
Bernardi, G., Ricciardi, E., Sani, L., Gaglianese, A., Papasogli, A., Ceccarelli, R., . . . Pietrini, P. (2013). How Skill Expertise Shapes the Brain Functional Architecture: An fMRI Study of Visuo-Spatial and Motor Processing in Professional Racing-Car and Naïve Drivers. PLoS ONE,8(10). doi:10.1371/journal.pone.0077764
Chase, W. G., & Simon, H. A. (1973). Perception in chess. Cognitive Psychology,4(1), 55-81. doi:10.1016/0010-0285(73)90004-2
Collard, M., Buchanan, B., Morin, J., & Costopoulos, A. (2011). What Drives the Evolution of Hunter–Gatherer Subsistence Technology? A Reanalysis of the Risk Hypothesis with Data from the Pacific Northwest. Culture Evolves, 341-358. doi:10.1093/acprof:osobl/9780199608966.003.0020
Dr. John R. Skoyles (1999) HUMAN EVOLUTION EXPANDED BRAINS TO INCREASE EXPERTISE CAPACITY, NOT IQ. Psycoloquy: 10(002) brain expertise
Gobet, F., & Simon, H. A. (1998). Expert Chess Memory: Revisiting the Chunking Hypothesis. Memory,6(3), 225-255. doi:10.1080/741942359
Herculano-Houzel, S., & Kaas, J. H. (2011). Gorilla and Orangutan Brains Conform to the Primate Cellular Scaling Rules: Implications for Human Evolution.
Lamberti, D. M., & Newsome, S. L. (1989). Presenting abstract versus concrete information in expert systems: what is the impact on user performance? International Journal of Man-Machine Studies,31(1), 27-45. doi:10.1016/0020-7373(89)90031-x
Lieberman, D. E., Raichlen, D. A., Pontzer, H., Bramble, D. M., & Cutright-Smith, E. (2006). The human gluteus maximus and its role in running. Journal of Experimental Biology,209(11), 2143-2155. doi:10.1242/jeb.02255
Lynn, R. (2006). Race differences in intelligence: An evolutionary analysis. Augusta, Ga.: Washington Summit Publishers.
Maguire, E. A., Gadian, D. G., Johnsrude, I. S., Good, C. D., Ashburner, J., Frackowiak, R. S., & Frith, C. D. (2000). Navigation-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences,97(8), 4398-4403. doi:10.1073/pnas.070039597
Torrence, R. (1983). Time budgeting and hunter-gatherer technology. In G. Bailey (Ed.). Hunter-Gatherer Economy in Prehistory: A European Perspective. Cambridge, Cambridge University Press.
Testosterone and Society
1050 words
In my last post on testosterone, I showed how the alarmism against having high testosterone is blown out of proportion. The hormone testosterone was extremely important in our evolutionary history, with skull changes that are affected by testosterone changing, indicating that it’s a cause of the rise of civilization. By looking at the skulls and skeletons of our hominin ancestors, we can infer how high the testosterone was due to changes in their skeletons over time. It seems that a decrease in testosterone was partly responsible for the advent of civilization, but too low of a dip is causing problems in the West.
Testosterone on its own is very important for male fertility, and confidence with there being no evidence showing causation in regards to prostate cancer. There are, however, large increases and dips and testosterone throughout evolutionary history. This can be inferred from looking at the skeletal remains of our ancestors.
One such study was completed by Cieri et al (2014). Cieri et al found that there was substantial feminization of Homo sapiens facial anatomy. Most notably there were reductions in average brow projection and the shortening of the upper facial skeleton. If you have knowledge of testosterone and its effects on the body, this is not surprising. Relaxing either testosterone or androgen sensitivity will cause softer, more feminized facial features over time. They argue that changes in craniofacial morphology reflects reduction in circulating levels of testosterone, “or reduced androgen receptor densities”, which, they argue “reflect the evolution of enhanced social tolerance since the Middle Pleistocene.”
The reduction in human craniomorphology coincides with larger populations from the Agricultural Revolution, which meant greater social tolerance and reduced aggression towards the group. Due to this, people were more altruistic to each other. Men that were more altruistic and had more pro-social behaviors, for instance, would be able to trade with other men in the band, which became sort of a fallback when they couldn’t forage any food. Over time, those men who could cooperate better (and had more feminized craniomorphology due to less circulating testosterone/androgen receptors).
Due to the selection of more pro-social behaviors, humans started becoming less aggressive and facial features became more feminized (due to less circulating testosterone/androgen receptors). Testosterone itself is correlated with aggressive behavior (Olweus et al, 1988) so with the selection against testosterone due to people who were more altruistic makes sense in this evolutionary context.
Cieri et al argue a good case—that the beginnings of behavioral modernity was due to selection against aggressive behavior, shifted towards pro-sociality. The fact that this began to occur around the Agricultural Revolution is no coincidence, in my opinion.
However, there seems to be a level of testosterone that a civilization needs to remain standing. Testosterone levels have reduced in the past two decades. Men are becoming more feminized, partly due to the environments we have constructed for ourselves. It’s in part due to the foods we eat/what we eat out of that is causing the drop. For instance, imagine being in an environment that destroys human testosterone levels. For instance, let’s say that a lot of the food we eat is made with/stored in a lot of BPA-containing storage. Over time, this would cause differing gene expression. People who are eating these testosterone-lowering foods will have children and, theoretically, pass on the genetically expressed genes to their children, in an epigenetic transference. Since those genes would then be advantageous in the environments we have constructed for ourselves, they would then get selected for. Once enough people get the gene in the population then it will reach fixation. That gene will then get selected in that population. If that gene is one that lowers testosterone, you will then begin to have a more feminized population (like we are seeing now, with men having lower levels of testosterone now than we did twenty years ago).
As I argued in my previous article on testosterone, what Rushton described in his 1988 paper was the Graeco-Roman elite did not breed due to having less circulating testosterone. As I have covered, low testosterone is correlated with having fewer children. As Rushton hypothesized, the elite did not breed while the lower classes did. We can look at it today and look at the ‘elite’ as upper-middle/upper class and look at the lower class, as, well the lower class. We do see the testosterone/class relationship today, with higher classes having lower levels of testosterone, vice versa for lower classes (Dabbs and Morris, 1990).
When looking at testosterone changes over time, fertility rates need to be looked at. Testosterone is down across the board all over the Western hemisphere, and it just so happens that the West is in a fertility crisis (with Europe having the lowest fertility in the world). Not surprisingly, testosterone is taking a dip in the West which is then having a negative effect on testosterone levels. This is due, partly, to the anti-testosterone environments that we have unknowingly (?) constructed for ourselves. To mediate these problems, we need to construct environments that keep testosterone levels raised as to side-step all of the horrible health problems associated with low testosterone, especially later in life.
So, since testosterone is the dominance/confidence/stress hormone, it’s clear that most men don’t put themselves into situations where the hormone would be heightened by the body. Testosterone levels do change throughout the day and depending on events that occur. If you’re around a lot of rowdy people, your testosterone will raise in response to the action around you. Testosterone rises significantly when in large groups and others around are committing violence and being destructive. This is natural, though. When this occurs, you’ll be at the ready for anything that happens, there will be no surprises. It’s a stress hormone, in that it rises mostly in stressful situations.
For society to form, there needed to be somewhat of a testosterone reduction throughout our evolutionary history. This allowed us to trade with each other and so, altruistic behaviors then were selected for. However, too much of a testosterone reduction within single populations leads to lower fertility, and, eventually, the fall of societies due to lower fertility rates. The key here is that we need to construct environments that encourage higher levels of testosterone. If something is not done, then Western society will fall sooner, rather then later (all things eventually come to an end; nothing lasts forever).
Evolution and IQ Linkfest II
1000 words
Why Grit Is More Important Than IQ When You’re Trying To Become Successful (Psychologist Angela Duckworth states that what matter for future life success isn’t IQ, SAT scores, or even graduating from a top college. What matters most for life success is a blend of perseverance and passion that she calls ‘grit’, in her book Grit: The Power of Passion and Perseverance. According to Duckworth, grittiness is passion, and being passionate about something will make you successful is persevering in the face of adversity; i.e., something not working out in your favor and you continue to go at it. She thought of two equations: talent x effort=skill, skill x effort=achievement. Talent is how quickly skills improve when effort is invested, whereas achievement occurs when you take the skills you acquired and put them to use. I’ll buy the book and read it and see what else she says.)
How Skill Expertise Shapes the Brain Functional Architecture: An fMRI Study of Visuo-Spatial and Motor Processing in Professional Racing-Car and Naïve Drivers (Brain functional architecture sustaining visuo-motor processing in racecar drivers “undergoes both ‘quantitative’ and ‘qualitative’ modifications that are evident even when the brain is engaged in relatively simple, non-demanding tasks.” Pretty much, get good at something, like really good, and your brain will change in size and mass.)
Acquiring ‘‘the Knowledge’’ of London’s Layout Drives Structural Brain Changes (Specific and enduring structural brain changes in adults “can be induced by biologically relevant behaviors engaging higher cognitive functions such as spatial memory.” Yet more evidence that becoming an ‘expert’ in something leads to substantial brain changes—which are permanent.)
Autism genes conserved during human evolution to make us smarter, say scientists (We were selected to be autistes since it was beneficial in our ancestral past. Autism is also associated with intellectual achievement.)
A model for brain life history evolution (As adult brain mass increases, so does skill, assumming the costs of maintaining brain mass and memories stay constant. This could be a cause for our larger brains. We know that our brains consume 20 ro 25 percent of our daily kcal, so in our evolutionary past, those who couldn’t amass the kcal to power the ever-growing brain would have died. González-Forero says that as we became proficient with tools, then our brain size began to increase. I have cited a few studies saying that over the past month.)
Lessons from Making Brain Soup (Learn about Herculano-Houzel and Lent’s 2005 Isotropic Fractionator—a machine that allows single cells in ‘brain soup’ to be counted as to get an accurate estimate of neurons.)
Numbers of neurons as biological correlates of cognitive capability (Body mass is a poor predictor of neurons, number of brain stem neurons estimates the capacity for processing bodily signals, mass of the cortex is a poor predictor of neuronal amount, the bird pallium packs more neurons than primate cortices of similar mass and finally the number of neurons in the cortex or pallium correlate directly with intelligence. Herculano-Houzel is blazing a new path in the field of neuroscience, with a novel way of looking at the brain showing that our brains are only scaled-up primate brains in terms of its neuronal composition.)
Creative People Have Better-Connected Brains, Scans Reveal (Highly creative people have more connections on the right and left sides of their brains, suggesting that creativity is biological in nature.)
Genetics Play a Role in Social Anxiety Disorder, Study Finds (Like most disorders, genetics plays a role. Whether it’s small or large, more often than not, genetics will always have at least a bit to say.)
Peer-review activists push psychology journals towards open data (An APA editor will not step down for stating that he won’t publish papers in which the authors don’t let their dataset become public. This is a great move. Why publish something that may possibly be garbage?)
We Look Like Our Names: The Manifestation of Name Stereotypes in Facial Appearance. (This is an interesting one, and one I’ve wondered my whole life since people have told me that ‘I don’t physically look’ how my name is. The researchers state that “facial appearance represents social expectations of how a person with a specific name should look.” Social tags influence one’s facial appearance.)
Greater insight into basic biology of pain will reveal non-addictive remedies (We need to better understand pain physiology, drug development and the individual response to pain in order to develop non-addictive drugs.)
Researchers Discover How Animals Measure Annual Time to Reproduce (The pituitary gland mediates when some mammals start reproducing. The length of the day is noticed in most animals by the pineal gland in the brain.
Does Cannabis Use Lower Your IQ? (No it does not. Recent longitudinal studies show that smoking marijuana does not lead to cognitive decline.
Reader’s Corner: Do we really understand animal intelligence? “Are We Smart Enough to Know How Smart Animals Are?” (We do not understand animal intelligence and we are not smart enough to know how smart animals are. We have an anthropocentric view of evolution, and thusly, we attempt to put our cognitive traits onto other animals when they are adapted for other areas. Herculano-Houzel’s research will begin to detangle this.)
Can Animals Acquire Language? (Evidence says no. However, I’m sure a few readers have heard of Koko the gorilla. She’s able to do sign language and has an estimated IQ of 75 to 95 on the Cattell Infant Intelligence Scale (pg. 99))
Dogs, toddlers show similarities in social intelligence (There is a g factor for dogs. The authors state that the similarities between child and dog intelligence could come down to ‘survival of the friendliest’. I’ll write about this soon.)
How Humans Became Intelligent (Cognitive neuroscientist and philosopher Daniel Dennet sees human consciousness as memetics and genetics. That is, we learn from others and what we are able to learn from others comes down to our genes. I will buy this book as well.)
The Testosterone and Fertility Conundrum: A Western Perspective
2750 words
Some people are scared of testosterone. This is no surprise, since a super-majority of people have no background in the human sciences. I’m sure plenty men know what it’s like to have low testosterone, just like some men know what it’s like to have higher T levels than average. What is the optimum level of testosterone? Why are some people scared of this hormone?
Rushton (1997) posited that r/K Selection Theory could be used to classify the races of Man on a spectrum, going from r-selection (having many children but showing little to no parental care) to K-selection (having fewer children but showing a lot of parental care). He stated that the traits of the races were also on the r/K spectrum, with the races having stark differences in morphology. Rushton’s application of r/K theory to humans isn’t completely wrong, though I do have some problems with some of his claims, such as his claims that the races differ in average penis size. He contends that testosterone is the cause for higher crime rates for black Americans and higher rates of prostate cancer in black Americans compared to white Americans.
However, in 2014, Richard et al showed that when controlling for age, blacks had 2.5 to 4.9 percent more testosterone than whites, on average. This cannot explain racial differences in prostate cancer. However, some people may emphatically claim that the races differ in average testosterone, with blacks having 13 percent higher free testosterone than whites on average. The citation that gets used the most to prove that blacks supposedly have higher testosterone than whites is Ross et al (1986), which is based on a sample of 100 people (50 black, 50 white). He claims that it’s when T levels are higher, so it’s a ‘better study’ even though the sample leaves a lot to be desired. A much more robust study showed that the difference was negligible, and not enough to account for the differential prostate cancer rates between the races.
Rohrmann et al (2007) show that there are no differences in circulating testosterone between blacks and whites in a nationally representative sample of American men. Mexicans had the highest levels. There were, however, B-W differences in estradiol production. They couldn’t confirm the other studies that stated that blacks had higher testosterone, possibly due to variations in age or using non-representative samples (that’s the culprit). Their nationally representative sample showed there was no difference in testosterone between blacks is whites, while the meta-analysis showed by Richard et al (2014) showed the difference was negligible at 2.5 to 4.9 percent higher rate of testosterone which doesn’t explain why blacks have a higher rate of acquiring prostate cancer.
The much more likely culprit for blacks having higher rates of prostate cancer, as I have written about before, are environmental factors. The two main factors are receiving less sunlight and diet. There is no evidence that higher levels of testosterone lead to prostate cancer (Michaud, Billups, and Partin, 2015). Contrary to those who say that higher levels of T cause prostate cancer, there is growing evidence that lower levels of T lead to prostate cancer (Park et al, 2015). Put simply, there is no evidence for testosterone’s supposed impact on the prostate (Stattin et al, 2013).
Differences in androgen/androgen receptors have been explained as a cause for racial differences in prostate cancer (Pettaway, 1999), however, these results haven’t been consistent (Stattin et al, 2003) and these differences in circulating androgen may possibly be explained by differences in obesity between the two populations (Gapstur et al, 2002; also see my posts on obesity and race).
Due to the ‘testosterone scare’, some people may believe that having low T is a ‘good thing’, something that’s preferred over being a high T savage. However, testosterone and the androgen receptor gene polymorphism are both associated with competitiveness and confidence in men (Eisenegger et al, 2016) and a reduced risk of cardiovascular disease in elderly men (Ohlsson et al, 2011). Obviously, lower testosterone is related to less overall confidence. People who have the thought in their head that testosterone is a ‘bad hormone’ will believe the negativity about it in the media and popular headlines.
Testosterone alone does not cause violence, but it does cause men to be socially dominant. Testosterone has been shown to increase in the aggressive phases of sports games and when shown artificial humans made to invoke physiologic responses, leading some researchers to argue that testosterone should be classified as a stress hormone. Testosterone does change based on watching one’s favorite soccer team winning or losing in a sample of 21 men (Bernhardt et al, 1998), lending some credence to the claim that testosterone is and should be classified as a stress hormone. Also of interest is that men who administered high levels of testosterone did not report higher levels of aggression (Batrinos, 2012).
I’ve heard some people literally say that having low testosterone is ‘a good thing’. People say this out of ignorance. There are a whole slew of problems associated with low testosterone, including but not limited to: insulin resistance in diabetic men (Grossmann et al, 2008); metabolic syndrome (Tsuijimura et al, 2013); muscle loss (Yuki et al, 2013); stroke and transient ischemic attack (a mini-stroke; Yeap et al, 2009); associated with elevated risk for dementia in older men (Carcaillon et al, 2014); myocardial infarction (heart attack) in diabetic men (Daka et al, 2015) etc. So it seems that the fear of testosterone from those in the anti-testosterone camp are largely blown out of proportion.
Testosterone is also a ‘food’ for the brain, with low levels being related to mental illness, sexual dysfunction, lower quality of life and cognitive impairment (Moffat et al, 2011) in both sexes (Ciocca et al, 2016). Noticed in both men in women with testosterone deficits were: cognitive impairment (reduction of working memory, episodic memory, processing speed, visual-spatial functioning and executive performance); a decrease in sexual activity; anxiety, schizophrenia, depression and stress; and alterations in cortical thickness in the brain. The fact that testosterone is so heavily important to the body’s central functioning is extremely clear. This is why it’s laughable that some people would be happy and brag about having low testosterone.
I recently came across a book called The Testosterone Hypothesis: How Hormones Regulate the Life Cycles of Civilization. Barzilai’s main premise is that the rise and fall of the West is mediated by the hormone testosterone, and due to lower testosterone levels this is one large reason for what is currently occurring in the West. The book has an extremely interesting premise. Barzilai’s hypothesis does line up with the declining levels of testosterone in America (Travison et al, 2007) though other research shows no decline in American testosterone levels from the years 88-91 to 99-04 (Nyante et al, 2007). Moreover, men who had higher level of n-6 in their blood then n-3 were far more likely to be infertile (Safarinejad et al, 2010) a marker of low testosterone (Sharpe, 2012). The ratio of n-6 to n-3 from the years 1935 to 1939 were 8.4 to 1, whereas from the years 1935 to 1985, the ratio increased to about 10 percent (Raper et al, 1992). The ratio of n-6 to n-3, on top of lowering sperm count (which is correlated with testosterone) also has negative effects on male and female cognitive ability (Lassek and Gaulin, 2011).
Barzilai’s research also corroborates Rushton’s (1986) theory of why there are lower birthrates for Europeans around the world. Rushton stated that this cycle has been noticed throughout history, with empires rising and falling due to differential birthrates between the ruling class and the ruled. Rushton also hypothesized that the cultures and gene pools associated with the Graeco-Roman empire were “evolutionary dead ends” (Rushton, 1986: 148). Knowing what we now know about the relationship between cognitive ability, testosterone, and fertility, we now have a plausible hypothesis for Rushton’s hypothesis and one of the (many) reasons why the Graeco-Roman empire collapsed. Rushton further hypothesized that the cause for lower fertility in European populations “may be partly mediated by a psychological process in which the desire to be in control of both oneself and one’s environment is taken to an extreme.” Of course there’s a good chance that this psychological process is mediated/influenced by testosterone.
Europe is the continent with the lowest fertility (ESHRE Capri Workshop Group, 2010). Testosterone has declined in Europe as a whole (Rivas et al, 2014), and this is a strong cause for the lower birthrates in Europe (along with genetic reasons) and in Finland (Perheentupa et al, 2013). The introduction of Westernized diets lowers testosterone, so this is no surprise that a reduction is seen in countries that begin to consume a Western diet. Another probable cause for lower testosterone/fertility in Europe at the moment is the large number of European men that died in WWI and WWII. Those that were more willing to fight died, meaning there was less of a chance he spread his genes. So, over time, this lead to the current cucking of Europe that we are now witnessing.
Testosterone is also hypothesized to have driven evolution (Howard, 2001). Testosterone is such an important part of human evolution and development, so much so that if we had a lower level of the hormone all throughout our evolution that we would be a different species today. Testosterone is needed for sexual functioning, good mental and brain health, fertility, cognitive ability, muscle mass retention in both young and old men, etc. Testosterone is one of the most important hormones for both men and women, and low levels for both sexes are detrimental to a high quality of life. The current data on testosterone and prostate cancer shows that higher levels of testosterone don’t contribute to prostate cancer. Testosterone, then, also isn’t a cause for the racial gap in prostate cancer because other environmental factors better explain it. If people really are happy about having lower testosterone, then I hope they have fun living a life with a low sex drive, lower cognition in old age, lower muscle mass and a higher chance of stroke and metabolic syndrome.
One of the most interesting things about testosterone is the possibility that it explains why civilizations rise and fall. There is anecdotal evidence from Rushton, as well as his theorizing that the higher classes in Rome didn’t breed which led to their downfall. We now know that lower fertility rates for men are associated with lower testosterone, so along with Barzilai’s thesis of testosterone causing the rise and fall of civilizations, Rushton’s theorizing of the cause of lower European fertility and the cause of the fall of the Graeco-Roman empire.
Testosterone is an extremely important hormone, one that drives human evolution and society formation since it’s associated with dominance and confidence. Low testosterone is looked at as ‘good’ because those with higher intelligence have lower levels of the hormone (indicated by lower confidence and having sex at a later age). I showed that the higher IQ East Asian men have a problem finding dates and being looked at as sexually attractive (even though they rated themselves as average). Along with lower East Asian fertility, specifically in Japan, does it seem to you like the high IQ people are more desired if they are having problems keeping their birthrates up? The fact of the matter is, lower levels of testosterone are correlated with lower levels of fertility. If men don’t have as much testosterone pumping through their veins, they will be less likely to have sex and thusly reproduce.
References
Batrinos, M. L. (2012). Testosterone and aggressive behavior in man. International Journal of Endocrinology & Metabolism,10(3), 563-568. doi:10.5812/ijem.3661
Bernhardt, P. C., Jr, J. M., Fielden, J. A., & Lutter, C. D. (1998). Testosterone changes during vicarious experiences of winning and losing among fans at sporting events. Physiology & Behavior,65(1), 59-62. doi:10.1016/s0031-9384(98)00147-4
Carcaillon, L., Brailly-Tabard, S., Ancelin, M., Tzourio, C., Foubert-Samier, A., Dartigues, J., . . . Scarabin, P. (2014). Low testosterone and the risk of dementia in elderly men: Impact of age and education. Alzheimer’s & Dementia,10(5). doi:10.1016/j.jalz.2013.06.006
Ciocca G, Limoncin E, Gravina GL, et al. Is testosterone a food for brain? Sex Med Rev 2016;4:15-25.
Daka, B., Langer, R. D., Larsson, C. A., Rosén, T., Jansson, P. A., Råstam, L., & Lindblad, U. (2015). Low concentrations of serum testosterone predict acute myocardial infarction in men with type 2 diabetes mellitus. BMC Endocrine Disorders,15(1). doi:10.1186/s12902-015-0034-1
Eisenegger, C., Kumsta, R., Naef, M., Gromoll, J., & Heinrichs, M. (2016). Testosterone and androgen receptor gene polymorphism are associated with confidence and competitiveness in men. Hormones and Behavior. doi:10.1016/j.yhbeh.2016.09.011
, , , , , . Serum androgen concentrations in young men: a longitudinal analysis of associations with age, obesity, and race—the CARDIA male hormone study. Cancer Epidemiol Biomarkers Prev 2002; 11: 1041–7
Grossmann, M., Thomas, M. C., Panagiotopoulos, S., Sharpe, K., Macisaac, R. J., Clarke, S., . . . Jerums, G. (2008). Low Testosterone Levels Are Common and Associated with Insulin Resistance in Men with Diabetes. The Journal of Clinical Endocrinology & Metabolism,93(5), 1834-1840. doi:10.1210/jc.2007-2177
Howard JM (2001): Androgens in human evolution. A new explanation of human evolution.
Lassek, W. D., & Gaulin, S. J. (2011). Sex Differences in the Relationship of Dietary Fatty Acids to Cognitive Measures in American Children. Frontiers in Evolutionary Neuroscience,3. doi:10.3389/fnevo.2011.00005
Michaud, J. E., Billups, K. L., & Partin, A. W. (2015). Testosterone and prostate cancer: an evidence-based review of pathogenesis and oncologic risk. Therapeutic Advances in Urology,7(6), 378-387. doi:10.1177/1756287215597633
Moffat, S. D., Zonderman, A. B., Metter, E. J., Blackman, M. R., Harman, S. M., & Resnick, S. M. (2002). Longitudinal Assessment of Serum Free Testosterone Concentration Predicts Memory Performance and Cognitive Status in Elderly Men. The Journal of Clinical Endocrinology & Metabolism,87(11), 5001-5007. doi:10.1210/jc.2002-020419
Nyante, S. J., Graubard, B. I., Li, Y., Mcquillan, G. M., Platz, E. A., Rohrmann, S., . . . Mcglynn, K. A. (2011). Trends in sex hormone concentrations in US males: 1988-1991 to 1999-2004. International Journal of Andrology,35(3), 456-466. doi:10.1111/j.1365-2605.2011.01230.x
Ohlsson C, Barrett-Connor E, Bhasin S, et al. High serum testosterone is associated with reduced risk of cardiovascular events in elderly men: the MrOS (Osteoporotic Fractures in Men) study in Sweden. J Am Coll Cardiol. 2011; 58(16):1674-1681.
Park, J., Cho, S. Y., Jeong, S., Lee, S. B., Son, H., & Jeong, H. (2015). Low testosterone level is an independent risk factor for high-grade prostate cancer detection at biopsy. BJU International,118(2), 230-235. doi:10.1111/bju.13206
Perheentupa, A., Makinen, J., Laatikainen, T., Vierula, M., Skakkebaek, N. E., Andersson, A., & Toppari, J. (2012). A cohort effect on serum testosterone levels in Finnish men. European Journal of Endocrinology,168(2), 227-233. doi:10.1530/eje-12-0288
Pettaway CA. Racial differences in the androgen/androgen receptor pathway in prostate cancer. J Natl Med Assoc 1999, 91: 653:650
Raper, N. R., Cronin, F. J., & Exler, J. (1992). Omega-3 fatty acid content of the US food supply. Journal of the American College of Nutrition,11(3), 304-308. doi:10.1080/07315724.1992.10718231
Richard, A., Rohrmann, S., Zhang, L., Eichholzer, M., Basaria, S., Selvin, E., . . . Platz, E. A. (2014). Racial variation in sex steroid hormone concentration in black and white men: a meta-analysis. Andrology,2(3), 428-435. doi:10.1111/j.2047-2927.2014.00206.x
Rivas AM, Mulkey Z, Lado-Abeal J, Yarbrough S. Diagnosing and managing low serum testosterone. Proc (Bayl Univ Med Cent) 2014;27:321-324
Rohrmann, S., Nelson, W. G., Rifai, N., Brown, T. R., Dobs, A., Kanarek, N., . . . Platz, E. A. (2007). Serum Estrogen, But Not Testosterone, Levels Differ between Black and White Men in a Nationally Representative Sample of Americans. The Journal of Clinical Endocrinology & Metabolism,92(7), 2519-2525. doi:10.1210/jc.2007-0028
Ross R, Bernstein L, Judd H, Hanisch R, Pike M, Henderson B. Serum testosterone levels in healthy young black and white men. J Natl Cancer Inst. 1986 Jan;76(1):45–48
Rushton, J. P. (1986). Gene-Culture Coevolution and Genetic Similarity Theory: Implications for Ideology, Ethnic Nepotism, and Geopolitics. Politics and the Life Sciences,4(02), 144-148. doi:10.1017/s0730938400004706
Rushton J P (1997). Race, Evolution, and Behavior. A Life History Perspective (Transaction, New Brunswick, London).
Safarinejad, M. R., Hosseini, S. Y., Dadkhah, F., & Asgari, M. A. (2010). Relationship of omega-3 and omega-6 fatty acids with semen characteristics, and anti-oxidant status of seminal plasma: A comparison between fertile and infertile men. Clinical Nutrition,29(1), 100-105. doi:10.1016/j.clnu.2009.07.008
Sharpe, R. M. (2012). Sperm counts and fertility in men: a rocky road ahead. EMBO reports,13(5), 398-403. doi:10.1038/embor.2012.50
Stattin, P., Lumme, S., Tenkanen, L., Alfthan, H., Jellum, E., Hallmans, G., . . . Hakama, M. (2003). High levels of circulating testosterone are not associated with increased prostate cancer risk: A pooled prospective study. International Journal of Cancer,108(3), 418-424. doi:10.1002/ijc.11572
Travison, T. G., Araujo, A. B., O’Donnell, A. B., Kupelian, V., & Mckinlay, J. B. (2007). A Population-Level Decline in Serum Testosterone Levels in American Men. The Journal of Clinical Endocrinology & Metabolism,92(1), 196-202. doi:10.1210/jc.2006-1375
Tsujimura, A., Miyagawa, Y., Takezawa, K., Okuda, H., Fukuhara, S., Kiuchi, H., . . . Nonomura, N. (2013). Is Low Testosterone Concentration a Risk Factor for Metabolic Syndrome in Healthy Middle-aged Men? Urology,82(4), 814-819. doi:10.1016/j.urology.2013.06.023
Yeap, B. B., Hyde, Z., Almeida, O. P., Norman, P. E., Chubb, S. A., Jamrozik, K., . . . Hankey, G. J. (2009). Lower Testosterone Levels Predict Incident Stroke and Transient Ischemic Attack in Older Men. Endocrine Reviews,30(4), 411-411. doi:10.1210/edrv.30.4.9994
Yuki, A., Otsuka, R., Kozakai, R., Kitamura, I., Okura, T., Ando, F., & Shimokata, H. (2013). Relationship between Low Free Testosterone Levels and Loss of Muscle Mass. Scientific Reports,3. doi:10.1038/srep01818
Heritability, the Grandeur of Life, and My First Linkfest on Human Evolution and IQ
1100 words
Benjamin Steele finally replied to my critique of his ‘strong evidence and argument’ on race, IQ and adoption. He goes on to throw baseless ad hominem attacks as well as appealing to motive (assuming my motivation for being a race realist; assuming that I’m a ‘racist’, whatever that means). When I do address his ‘criticisms’ of my response to him, I will not address his idiotic attacks as they are a waste of time. He does, however, say that I do not understand heritability. I understand that the term ‘heritable’ doesn’t mean ‘genetic’. I understand that heritability is the proportion of phenotypic variance attributed to genetic variance. I do not believe that heritability means a trait is X percent genetic. 80 percent of the variation in the B-W IQ gap is genetic, with 20 percent explained by environmental effects. Note that I’m not claiming that heritable means genetic. All that aside, half of his reply to me is full of idiotic, baseless and untrue accusations which I will not respond to. So, Mr. Steele, if you do decide to reply to my response to you this weekend, please leave the idiocy at the door. Anyway, I will tackle that this weekend. Quick note for Mr. Steele (in case he reads this): if you don’t believe me about the National Crime and Victimization Survey showing that police arrest FEWER blacks than are reported by the NCVS, you can look it up yourself, ya know.
I’m beginning to understand why people become environmentalists. I’ve recently become obsessed with evolution. Not only of Man, but of all of the species in the world. Really thinking about the grandeur of life and evolution and what leads to the grand diversity of life really had me thinking one day. It took billions of years for us to get to the point we did today. So, why should we continue to destroy environments, displacing species and eventually leading them to extinction? I’m not saying that I fully hold this view yet, it’s just been on my mind lately. Once a species is extinct, that’s it, it’s gone forever. So shouldn’t we do all we possibly can to preserve the wonder of life that took so long to get to the point that we did today?
Some interesting articles to read:
Study: IQ of firstborns differ from siblings (This is some nice evidence for Lassek and Gaulin’s theory stating why first-born children have higher IQs than their siblings: they get first dibs on the gluteofemoral fat deposits that are loaded with n-3 fatty acids, aiding in brain size and IQ.)
Why attitude is more important than IQ (Psychologist Carol Dweck states that attitude is more important than IQ and that attitudes come in one of two types: a fixed mindset or a growth mindset. Those with a fixed mindset believe ‘you are who you are’ and nothing can change it while those with a growth mindset believe they can improve with effort. Interesting article, I will find the paper and comment on it when I read it.)
Positively Arguing IQ Determinism And Effect Of Education (Intelligent people search for intellectually stimulating things whereas less intelligent people do not. This, eventually, will lead to the construction of environments based on that genotype.)
A scientist’s new theory: Religion was key to humans’ social evolution (Nicholas Wade pretty much argues the same in his book The Faith Instinct: How Religion Evolved and Why It Endures. It is interesting to note that archaeologists have discovered what looks to be the beginnings of religiousity around 10kya, coinciding with the agrigultural revolution. I will look into this in the future.)
Galápagos giant tortoises show that in evolution, slow and steady gets you places (Interesting read, on tortoise migration)
Will Mars Colonists Evolve Into This New Kind of Human? (Very interesting and I hope to see more articles like this in the future. Of course, due to being a smaller population, evolution will occur faster due to differing selection pressures. Smaller populations incur more mutations at a faster rate than larger populatons. Will our skin turn a reddish tint? Bone density will decline leading to heavier bones. The need for C-sections due to heavier bones will lead to futher brain size increases. This is also going on on Earth at the moment, as I have previously discussed. Of course differences in culture and technology will lead the colonizers down different paths. I hope I am alive to see the first colonies on Mars and the types of long-term effects of the evolution of Man on the Red Planet.)
Evolution debate: Are humans continuing to evolve? (Of course we are)
Did seaweed make us who we are today? (Seaweed has many important vitamins and minerals that are imperative for brain development and growth—most importantly, it has poly-unsaturated fatty acids (PUFAs) and B12. We are only able to acquire these fatty acids through our diet—our body cannot synthesize the fatty acid on its own. This is just growing evidence for how important it is to have a good ratio of n-3 to n-6.)
Desert people evolve to drink water poisoned with deadly arsenic (More evidence for rapid evolution in human populations. AS3MT is known to improve arsonic metabolism in Chile and Argentina. Clearly, those who can handle the water breed/don’t die while those who cannot succumb to the effects of arsenic poisoning. Obviously, over time, this SNP will be selected for more and more while those who cannot metabolize the arsonic do not pass on their genes. This is a great article to show to anti-human-evolution deniers.)
Here Are the Weird Ways Humans Are Evolving Right Now (CRISPR and gene editing, promotion of obesity through environmental factors (our animals have also gotten fatter, probably due to the feed we give them…), autism as an adaptation (though our definition for autism has relaxed in the past decade). Human evolution is ongoing and never stops, even for Africans. I’ve seen some people claim that since they never left the continent that they are ‘behind in evolution’, yet evolution is an ongoing process and never stops, cultural ‘evolution’ (change) leading to more differences.)
‘Goldilocks’ genes that tell the tale of human evolution hold clues to variety of diseases (We really need to start looking at modern-day diseases through an evolutionary perspective, such as obesity, to better understand why these ailments inflict us and how to better treat our diseases of civilization.)
Understanding Human Evolution: Common Misconceptions About The Scientific Theory (Don’t make these misconceptions about evolution. Always keep up to date on the newest findings.)
Restore Western Civilization ( Enough said. As usual, gold from Brett Stevens. Amerika.org should be one of the first sites you check every day.)
I guess this was my first linkfest (ala hbd chick). I will post one a week.
Genetic Changes from Cooking
2600 words
The debate about cooking’s role in human evolution is ongoing. Some people may rightly say “Cooking it not a selection pressure.” This is true. However, it doesn’t say much. The advent of cooking was one of the most important events in human history as it released the constraint on brain size due to predigesting our food outside the body. This seminal event in our history here on earth is one of the main reasons we are here today. In the articles I wrote two months ago on how and why we are so intelligent, I forgot to bring up two important things—the thermic effect of food (TEF) and our gut microbiota and its relationship with our brain. The importance of these variables in regards to cooking cannot be overstated. The subject tonight is cooking and how it benefitted us metabolically and our gut microbiota that partly drive our brain and behavior.
Cooking was beneficial to us not only because it released constraints on brain size due to how nutrient-rich meat was as well as other foodstuffs that were then cooked, but because it’s possible to extract more energy out of cooked food compared to non-cooked food. When erectus began controlling fire around 1-1.5 mya (Herculano-Houzel, 2016: 192) this allowed for the digestion of higher-quality foods (meat, tubers, etc) and this is the so-called ‘prime mover’ for the brain size increase in hominids over the past 3my.
The introduction of cooked/mashed foods changed the shape of the ridges on our skull which serve as attachments for the facial muscles responsible for chewing. The saggital crest on the cranium and zygomatic eminences in the cheeks exist in great apes but not us. Further, molars and canine teeth reduced in size while brain size double in erectus. Our jaw bones decreasing in size shows that we didn’t need to have as forceful of a bit due to the introduction of cooked foods 1-1.5 mya (Herculano-Houzel,2016: 193).
Along with the introduction to a diet with softer foods, smaller teeth and intestines then followed. So brain size and teeth size are not correlated per se, neither are brain size and gut size. However, the relationship between all three is cooking: cooking denatures the protein contained in the food and breaks down cell walls, gelatinizing the collagen in the meat allowing for easier chewing and digestion. So the fact that tooth size and brain size do not have a relationship throughout our evolution is not a blow to the cooking hypothesis. The introduction of softer foods is the cause for both the decrease in tooth size and gut size. Cooking is a driver of all three.
Fonseca-Azevedo and Herculano-Houzel (2012) showed that the availability of kcal from a raw diet is so limiting that without a way to overcome this limitation, modern Man would not have been able to evolve. Our brains would not have emerged if not for the advent of cooking. Indeed, Herculano-Houzel and Kaas (2011) showed that the outler is not our brains being bigger than our bodies, great apes have bodies too big for their brains, reversing a long-held belief on our brain-body relationship. Cellular scaling rules apply for all primates, so knowing this, the Colobinae (old-world monkeys) and the Pongidae (gorillas, chimpanzees, and orangutans) favored increases in body size, in line with the ancestor that we share with great apes, while our lineages showed gains in brain size and not body size, possibl due to a metabolic limitation of having both a big brain and body. Indeed, the amount of neurons a brain can hold along with how big a body can realistically get impedes the relationship between the brain and body. You can have either brains or brawns, you can’t have both.
We should then look for when genetic changes in our genome occurred from cooking. Carmody et al (2016) show that these genetic changes occured around 275-765kya. We know that differing nutrients change gene expression, so, over time, if these changes in gene expression were beneficial to the hominin lineage, there would be positive selection for the gene expression. Carmody et al (2016) took 24 mice and fed them either cooked or raw foods for 5 days. Two hours into the 5th day, mice were ‘sacrificed’ (killed) and their liver tissue was harvested and immediately (within 60 seconds of death) were flash frozen for later analysis. They evaluated differential gene expression for cooked/raw food, calorie intake (raw/fed), energy balance of the consusmer (weight gain/loss over 5 days of feeding), and food type (meat/tuber). The diet consisted of either organic lean beaf round eye toast or sweet potato tubers cooked or raw. They gave restricted rations to evaluate the effect of a cooked diet with negative energy status (this is important).
They cooked the meat until it gelatinized (around 70 degress celsius), which is equivalent to medium well-done. They were then given the same diets, cooked/raw, free-fed or restricted sweet potato tubers or meat. The mice were weighed during periods of inactivity and the food they refused to eat was weighed to monitor fresh weight than freeze-fried to monitor dry weight.
The most interesting part of this experiment, in my opinion, was that the mice that were free-fed with cooked diets consumed less kcal than the mice that were free-fed raw diets. They discovered that free-fed cooked diets led to the maintenance of body weight, whereas the free-fed raw diet led to weight loss. This confirms that cooked food gives more energy than raw food, which was itelf a critical driver in our evolution as humans.
When they looked at the livers of the sacrificed mice, they found that the mice that were fed meat showed liver gene expression patterns that were more similar to mice fed a human diet than mice that were fed tuber. The mice that were fed cooked food showed similar gene expression to mice fed a human diet and more similar to the human liver than in the mice fed the raw food. Even more interestingly, the mice fed tuber or raw foods exhibited liver expression patterns more similar to mice fed a chimpanzee diet and gene expression patterns noticed in non-human primates. Their analysis on the gene expression from cooked/raw diets compared to another data set showed that these genes that were expressed went under selection between 275-765kya.
Food type and preparation were associated with significant changes in gene expression, but those related to cooking were shown to have evidence of possible selection in the timeframe state by Carmody et al. These results also show that along with cooking increasing the bioavailability of foods, habitual cooking would have led to less energy spent on immune upregulation. This energy could then be used for other bodily processes—like our increasing brain size/neuronal count.
Carmody et al show that the biological evidence for cooking is 2mya, archaeological evidence 1mya, hearths 300kya, not too many Neanderthals controlled fire until 40 kya, and the earliest direct evidence we have of cooking appears around 50kya. We can obviously look at physiological, metabolic and diet differences between hominins and infer what was eaten. Now with looking at changes in gene expression, we can pinpoint when the positive selection began to occur. The biological evidence, in my opinion, is the best evidence. We don’t need direct physical evidence of cooking, we can make inferences based on certain pieces of knowledge we have. All in all, this new study by Carmody et al show that 1) cooking definitely predated modern humans and 2) many different hominins practiced cooking. This evidence shows that cooking for ancient hominins occurred way earlier than the archaeological record suggest.
Now, remember how the mice free-fed on a cooked meat diet ate less yet maintained their weight? There is a reason for this. Protein is the most filling macro (followed by fat, fiber then CHO). So it’s no surprise that the mice at less of the cooked meat. What was a surprise was that the mice maintained their weight eating less kcal then the mice that ate a raw foods diet. This is yet more evidence that cooking released us from the metabolic constraints of a raw, plant-based diet.
For those who have some knowledge of human metabolism, you may have heard of the thermic effect of food. The thermic effect of food is the amount of energy expenditure above the basal metabolic rate due to the cost of processing food and its storage. So if you’re cooking food before you ingest it, you bypass a lot of the processing that happens internally after digestion, allowing you to extract close to 100 percent of the kcal contained in the food. Due to cooking’s effects on foods, since we our bodies have to use some of the energy we consume to function and process the kcal, getting higher quality food was beneficial to us since we could have more for our bodily functions and to power our growing brains. Since we were able to get higher quality calories from cooked food, the effects of TEF weren’t as large, which was yet another constraint that we bypassed with a cooked diet. A cooked diet is more efficient than a raw one in more ways than one.
One more thing I forgot to mention in my series of articles on the benefits of cooking and human evolution is the effect it had on our microbiome. The completion of the Human Microbome Project (HMP) was imperative to our understanding of the trillions of bacteria that live in our guts. It was commonly stated that the bacteria in our guts outnumbered regular bacteria with a 10:1 ratio. However, Sender, Fuchs, and Milo (2016) showed that on average, there is about a 1:1 ratio with about 30 trillion normal bacteria and 39 trillion gut bacteria, some people possibly having double the amount of gut bacteria in comparison to regular bacteria, but nowhere on the level of 10:1 that has been stated for the past 40 years.
The human microbiome has undergone a substantial change since the divergance of humans and chimpanzees (Moeller et al, 2014). Over the course of our evolutionary history, our microbiome has become specialized to animal-based diets. Wild apes have way more diversity in their gut microbiota than humans do, indicating that we have experienced a depletion in our microbiota since our divergence with chimpanzees. This comes as no surprise. With the introduction to cooked foods, our microbiota became adapted to a new selective pressure. Over time, our gut microbiota became less diverse but more and more specialized to consume the food we were eating. So the introduction to a cooked diet both changed our gut microbiota as well as giving our bodies enough energy to power itself and its processes, the brain and our gut microbiota that are imperative for our development.
All that being said, some people may say “Cooking isn’t a selective pressure; neither is bipedalism nor tool-making”, and they would be correct. However, human tool-making capacities reflect increased information-processing capabilities (Gibson, 2012). So, clearly, there were some changes in our brains before the use of tools. This change was the advent of bipedalism which allowed our bodies to conserve 75 percent more energy in comparison to knuckle-walking (Sockol, Racihlen, and Pontzer, 2007). This was yet another constraint that we bypassed and allowed our brains to grow bigger. When we left the trees, we then became bipedal and that therefore increased the availability of edible foodstuffs for us. This increased our brain size, and as we learned to make tools, that increased our information-processing capabilities.
Cooking, of course, is not a selective pressure. What cooking did, however, was release the use from the metabolic constraints of a raw, plant-based diet and allowed us to extract all of the nutrients from whatever cooked food we ate. This event—one of the most important in human history—would only have been possible with the advent of bipedalism. After we became bipedal we could then manipulate our environement and make tools.
I figure I may as well touch on the Expensive Tissue Hypothesis (ETH; Aiello and Wheeler, 1995) while I’m at it. The ETH states that since our guts are metabolically expensive tissue—as well as our brains—that there was a trade off in our evolutionary history between our brains and guts. However, Navarette, Schaik and Isler (2011) showed that the negative correlation was with fat-free mass and brain size—not with the gut and brain size. However, as I noted earlier in this article, our guts reduced in size due to diet quality, e.g., softer foods. So while the correlation is there for the brain size increase/gut reduction, it is not causal. Diet explains the gut reduction and brain size increase, but the brain size increase did not cause the gut reduction.
In sum, genetic changes from cooking occured between 275-765kya. But we controlled fire and began to cook between 1-2mya (archaeological evidence says 1-1.5 mya while biological evidence says 2 mya). Cooking led to differences in gene expression and then positive selection in the hominin lineage. Mice that were fed a raw diet showed gene expression similar to a chimpanzee fed a raw diet while mice fed a cooked diet showed gene expression like that of a human. This is huge for the cooking hypothesis. What this shows is that while the gene expression occurred while we started cooking, the actual positive selection didn’t occur in our genomes for about 1my after we began cooking. This is more evidence that cooking released us from metabolic constraints, as mice that were fed a cooked diet maintained their weight even when eating less kcal than mice fed raw foods.
When thinking about the evolution of Man and our relationship with fire, we should not forget about how the body uses some of the kcal is ingests for bodily processes. Furthermore, we cannot forget about our microbiome which evolved for an animal-based diet. Those two things both cost caloric energy. The advent of cooking released us from the energetic constraints of a raw, plant-based diet as well as gave our microbiome higher quality energy. When we take both the TEF and our microbiome into account, we can then begin to put 2 and 2 together and state that along with cooking freeing us from the metabolic constraints that apes have to go through due to their diet, it also benefitted our microbiome and gave our bodies higher quality energy to power it.
We would not be here without cooking. Thank cooking for our dominance on this planet.
References
Aiello, L. C., & Wheeler, P. (1995). The Expensive-Tissue Hypothesis: The Brain and the Digestive System in Human and Primate Evolution. Current Anthropology,36(2), 199-221. doi:10.1086/204350
Carmody, R. N., Dannemann, M., Briggs, A. W., Nickel, B., Groopman, E. E., Wrangham, R. W., & Kelso, J. (2016). Genetic Evidence of Human Adaptation to a Cooked Diet. Genome Biology and Evolution,8(4), 1091-1103. doi:10.1093/gbe/evw059
Fonseca-Azevedo, K., & Herculano-Houzel, S. (2012). Metabolic constraint imposes tradeoff between body size and number of brain neurons in human evolution. Proceedings of the National Academy of Sciences,109(45), 18571-18576. doi:10.1073/pnas.1206390109
Gibson, K. R. (2012). Human tool-making capacities reflect increased information-processing capacities: Continuity resides in the eyes of the beholder. Behavioral and Brain Sciences,35(04), 225-226. doi:10.1017/s0140525x11002007
Herculano-Houzel, S. (2016). The Human Advantage: A New Understanding of How Our Brains Became Remarkable. doi:10.7551/mitpress/9780262034258.001.0001
Herculano-Houzel, S., & Kaas, J. H. (2011). Gorilla and Orangutan Brains Conform to the Primate Cellular Scaling Rules: Implications for Human Evolution.
Moeller AH, Li Y, Mpoudi Ngole E, Ahuka-Mundeke S, Lonsdorf EV, Pusey AE, et al. Rapid changes in the gut microbiome during human evolution. Proceedings of the National Academy of Sciences. 2014;111(46):16431–35.
Navarrete, A., Schaik, C. P., & Isler, K. (2011). Energetics and the evolution of human brain size. Nature,480(7375), 91-93. doi:10.1038/nature10629
Sender, R., Fuchs, S., & Milo, R. (2016). Revised estimates for the number of human and bacteria cells in the body. doi:10.1101/036103
Sockol, M. D., Raichlen, D. A., & Pontzer, H. (2007). Chimpanzee locomotor energetics and the origin of human bipedalism. Proceedings of the National Academy of Sciences,104(30), 12265-12269. doi:10.1073/pnas.0703267104
Is Obesity Genetic? A Reply to PumpkinPerson and Robert Lindsay
1200 words
I come across a lot of ridiculous articles from PumpkinPerson, but this has to be one of the most ridiculous. He writes:
Identical twin studies show that obesity has a heritability of almost 80%. Although I generally lean towards nature in most nature-nurture debates, I’ve always had a problem with the idea that obesity is highly genetic, and thus enjoyed this epic rant by blogger Robert Lindsay:
It is 80% genetic[?]
That is why you have whole tribes in South America where not one person has ever been fat.
That is why you have whole towns in Melanesia with 1000’s of people where not one person is fat.
There are fat people in the cities of Solomon Islands. In the study I read, the only man who was fat was one who had gone off to the city for a while and ate salt and processed, packaged food. Do you realize that if you did a genetic study of the fatties in Melanesia, you would find that wonderful 80% “genetic” link you guys are shouting about?
That is why the fatness and obesity rate has exploded in the US and much of the rest of the world. Because it’s 80% genetic!
I do not believe that fatsos act just like the rest of us. Ever known a blimp who ate like a bird? Me either.
I dunno about you, but I have never seen a fat person who wasn’t stuffing their face all the time with lousy food. They are always in restaurants. Always going out to eat. If you go to a restaurant, look around at all the fat people. Those people are fat because fat people like to eat out all the time and restaurant food is fattening. Fat people love to eat. Have you ever noticed that?
It’s 80 percent heritable in first world countries. Obviously the heritability will be lower in the third world. Clearly in first-world countries we have an overabundance of food. We don’t know what to do with it. So instead of having the opposite problem (not enough food) we now have too much food and this is what caused weight to increase (along with added sugars processed carbs).
Look at Melanesia—they still eat an ancestral diet. I can’t tell if Lindsay is being serious or not. He’s comparing people who still eat their ancestral diet to people who live in first-world countries and eat a Western diet. There’s no comparison there. If you want to see why people aren’t fat nor have the same diseases at the same rates (they are low to nonexistent in places like that) read Agriculture and Diseases of Civilization.
This is the study that’s being referred to Elks et al 2012. The heritability of BMI is between .75 and .82. Again: this is in first-world countries.
PP then says:
In fact just the other day, I was at the home of someone who was so incredibly fat I thought “it must be genetic.” And then just as I was leaving his house, I noticed a huge empty box of pizza in the kitchen.
Binge eating and obesity both have a heritable component (Bulk, Sullivan and Kendler, 2003). Further, to quote Gary Taubes from Why We Get Fat and What to Do About It:
“So maybe the answers to be found are in the integration of factors – starting with the physiological, metabolic, and genetic ones and letting them lead us to the environmental triggers. Because the one thing we know for sure is that the laws of thermodynamics, true as they always are, tell us nothing about why we get fat or why we take in more calories than we expend while it’s happening. (emphasis mine) (Taubes, 2011: pg 74, excerpt from Why We Get Fat and What to Do About It)
PP says:
The fatness itself or the tendency to engage in behaviors that cause fatness such as ordering large pizzas? So while obesity might technically be nearly 80% genetic, the statistic is misleading because it’s not directly genetic in the same was as height is.
If you don’t eat enough, nor get the right nutrients, you don’t hit your genetic height. If you don’t eat enough you don’t hit your genetic weight.
I don’t get why studies like this get generalized to the whole population. This study was done in first-world countries and so this only applies to first-world countries. You’d think that people who think they know science would know that studies are only applicable for the cohort and people they are done on. Guess not.
Of course I don’t deny obesity has some direct genetic component. Some people gain weight a lot easier than others and for some people, it’s virtually impossible to lose weight no matter how well they eat, though this is rare.
Of course some people gain weight easier than others. Some people lose weight easier than others. Much of the biological opposition to sustained weight loss is due to the hormone leptin (Rosenbaum et al, 2010). The more fat you have in your body, the more leptin you have. Moreover, the longer you are at a certain weight, the more likely it is that is your bodyweight set-point and thus you can only move up or down at around a range of 10 to 15 pounds. Also see this quote from neuroscientist Sandra Aamodt’s book Why Diets Make Us Fat (see her Ted Talk here):
Like nearsightedness, environmental influences on weight also mostly affect the genetically vulnerable, although we understand the details of the process in only rare cases. Fitness gains on a standardized exercise program vary from one person to another largely because of differences in their genes. When identical twins, men in their early twenties, were fed an extra thousand calories per day for about three months, each pair showed similar weight gains . In contrast, the gain varied across twin pairs, ranging from nine to twenty-nine pounds, even though the caloric imbalance was the same for everyone. An individual’s genes also influence weight loss. When another group of identical twins burned a thousand more calories per day through exercise while maintaining a stable food intake in an in-patient facility, their losses ranged from two to eighteen pounds and were even more similar within twin pairs than weight gain. (Aamodt, 2016 pg. 138)
The cold, hard truth is that dieting doesn’t have a good track record. See Mann et al (2007) here. People don’t understand the bodies’ biological processes and assume something is easy while being ignorant to how the body reacts under caloric deprivation. This wouldn’t happen if people actually had some knowledge of human physiology. Something that PP and RL lack. They are speaking about a complex problem than they’re too ignorant to really know about.
PP then says:
“Now I have no doubt that if that person has an identical twin raised apart, he too is extremely fat, and thus fatness technically has a high heritability, but what exactly is genetic here?”
Would the identical twin be raised in an obesogenic environment? If so, there’s a high chance that, yes he’d be fat too.
It’s also true that most people who lose weight end up gaining it back, but that’s because they end up returning to their compulsive eating habits.
Most people do end up gaining it back but it has to do with biological and physiological processes; obesity has nothing to do with willpower. You can’t willpower your way to extra weight loss.
People should read a few papers and books to see some data and facts before they write what “sounds good” in their head. These two clearly have no idea what they’re talking about and clearly talking from emotion and what sounds good.
Also read Are There Genetic Causes for Obesity?
An Evolutionary Look At Obesity
2050 words
Diet is the main driver of our evolution. Without adequate energy, we wouldn’t be able to able to have a brain as large as we do that has the number of neurons we have due to how calorically expensive each neuron is (6 kcal per billion neurons). However, as I’m sure everyone can see, our current diets and environment has caused the current obesity crisis in the world. What is the cause of this? Our genomes are adapted for a paleolithic diet and not our modern environment with processed foodstuffs along with an overabundance of energy. With an overabundance of novel food items and situations due to our obesogenic environments, it is easier for a higher IQ person to stay thinner than it is for a lower IQ person. Tonight I will talk about the causes for this, how and what we evolved to eat and, of course, how to reverse this phenomenon.
“Gourmet Sapiens” arose around 1-1.5 mya with the advent of cooking by Homo erectus. Even before then, when we became bipedal our hands were freed which then allowed us to make tools. With these tools, we could mash and cut food which was a sort of pre-digestion outside the body (exactly what cooking is). Over time, our guts shrank (Aiello, 1997) and we became adapted for a certain diet (Eaton, 2006). Over time, we evolved to eat a certain way—that is, we had times of feast and famine. Due to this, eating three meals a day is abnormal from an evolutionary perspective (Mattson et al, 2014). This sets the stage for the acquisition of diseases of civilization along with the explosion of obesity rates.
When looking for the causes—and not symptoms—of the rise of obesity rates, the first thing we should do is look at our current environment. How is it constructed? What type of foodstuffs are in it? What kinds of foods get advertised to us and how does this have an effect on our psyche and what we eventually buy? All three of these questions are extremely important to think of when talking about why we are so obese as a society. First-world environments are obesogenic (Galgani and Ravussin, 2008) due to being evolutionarily novel. Our genomes are adapted to a paleolithic diet, and so the introduction of the neolithic diet and agriculture reduced our quality of life, with a marked decrease in the quality of skeletal remains discovered after the advent of agriculture. However, agriculture is obviously responsible for the population boom that allowed us to become the apes the took over the world, cause being the population boom that followed the agricultural revolution (Richards, 2002).
Evolutionary mismatches occur when the rate of cultural or technological change is far faster than the genome can change to adapt to the new pressure. These dietary mismatches occur when cultural and technological change which can vastly outstrip biological evolution. The two big events that occurred in human history that have vastly outstripped biological evolution are the agricultural and Industrial Revolution. Contrary to Ryan Faulk’s belief, East Asians are not ‘less sensitive to carbohydrates’ and he did not “solve Gary Taubes’ race problem” in regards to diabesity rates. The rate of cultural and technological change has had large deleterious effects on our quality of life, and our increasing obesity rates have a lot to do with it.
Cofnas (2016) showed that mice taken off of their ancestral diet lead to worse healthy outcomes. The results of Lamont et al (2016) show that we, as animals, are adapted for ancestral diets, not the diets of the environment we have currently made for ourselves. This is a big point to take home from this. All organisms are adapted/evolved for what occurred in the ancestral past, not any possible future events. Therefore, to be as healthy as possible, it stands to reason you should eat a diet that’s closer to the ones your ancestors ate, especially since it can reverse type II diabetes and reverse bad blood markers (Klonoff, 2009). Even a short-term switch to a paleo diet “improves BP and glucose tolerance, decreases insulin secretion, increases insulin sensitivity and improves lipid profiles without weight loss in healthy sedentary humans.” (Frassetto et al, 2009) Since we evolved for a past environment and not any possible future ones, then eating a diet that’s as close as possible to our paleolithic ancestors looks like a smart way to beat the evolutionary mismatch in terms of our new, current obesogenic environment.
In one extremely interesting study, O’dea (1984) took ten middle-aged Australian Aborigines with type 2 diabetes and had them return to their ancestral hunter-gatherer lifestyle. With seven weeks of an ancestral diet and exercise, the diabetes had almost completely reversed! Clearly, when the Aborigines were taken off of our Western diet and put back in their ancestral environment with their ancestral diet, their diabetes disappeared. If we went back to a more ancestral eating pattern, the same would happen with us. This one small study lends credence to my claim that we need to eat a diet that’s more ancestral to us for us to ameliorate diseases of civilization (Eaton, 2006).
Further, looking at obesity from an evolutionary perspective can and will help us understand the disease of obesity (Ofei, 2005) better. Speakman (2009) reviewed three different explanations of the current obesity epidemic and assessed their usefulness in explaining the epidemic. The thrifty gene hypothesis states that obesity is an adaptive trait, that people who carry so-called ‘thrifty genes’ would be at an adaptive advantage. And since we have an explosion of obesity today from the 70s to today, this must explain a large part of the variance, right? There is evidence pointing in this direction, however (Southam et al, 2009). The second cause that Speakman looks at is the adaptive viewpoint—that obesity may have never been advantageous in our history, but genes that ultimately predispose us to obesity become “selected as a by-product of selection on some other trait that is advantageous.” (Speakman, 2009) The third and final perspective he proposes is that it’s due to random genetic drift, called ‘drifty genes’, predisposing some—and not others—to obesity. Whatever the case may be, there is some truth to their being genetic factors involved in the acquisition of fat storage. Though drifty genes and the adaptive viewpoint on obesity make more sense than any thrifty gene hypothesis.
For there to be any changes in the rate of obesity in the world, we need to begin to change our obesogenic environments to environments that are more like our ancestral one in terms of what foods are available. Once we alter our obesogenic environment into one that is more ancestrally ‘normal’ (since we are adapted for our past environments and not any possible future ones) then and only then will we see a reduction in obesity around the world. We are surrounded and bombarded with ads since we are children, which then effects our choices later in life; children consume 45 percent more when exposed to advertising (Harris et al, 2009). Clearly, advertisements can have one eat more, and the whole environmental mismatch in regards to being surrounded by foodstuffs not ancestral to us causes the rate of obesity to rise.
Finally, one thing we need to look at is the n-3 to n-6 ratio of our diets. As I covered last month, the n-6/n-3 is directly related to cognitive ability (Lassek and Gaulin, 2011). Our obesogenic environments cause our n-3/n-6 levels to be thrown out of whack. Our hunter-gatherer ancestors had a 1:1 level of n-3 and n-6 (Kris-Etherton, 2000). However, today, our diets contain 14 to 25 times more n-6 than n-3!! Still wondering why we are getting stupider and fatter? Further, Western-like diets (high in linolic acid; an n-6 fatty acid) induces a general fat mass enhancement, which is in line with the observation of increasing obesity in humans (Massiera et al, 2010). There is extreme relevance to the n-3/n-6 ratio on human health (Griffin, 2008), so to curb obesity and illness rates, we need to construct environments that promote a healthy n-3/n-6 ratio, as that will at least curb the intergenerational transmission of obesity. Lands (2015) has good advice: “A useful concept for preventive nutrition is to NIX the 6 while you EAT the 3.” Here is a good list to help balance n-6 to n-3 levels.
In sum, obesity rates are a direct product of obesogenic environments. These environments cause obesity since we are surrounded by evolutionary novel situations and food. The two events in human history that contribute to this is the agricultural and Industrial Revolution. We have paleolithic genomes in a modern-day world, which causes a mismatch between our genomes and environment. This mismatch can be ameliorated if we construct differing environments—ones that are less obesogenic with less advertisement of garbage food—and we should see rates of obesity begin to decline as our environment becomes more and more similar to our ancestral one (Genné-Bacon, 2014).
The study on mice showed that for them to be healthy they need to eat a diet that is ancestral to them. We humans are no different.The evidence from the study on Australian Aborigines and the positive things that occur after going on a paleo diet for humans—even for sedentary people—shows that for us to be as healthy as possible in these obesogenic environments that we’ve made for ourselves, we need to eat a diet that matches with our paleolithic genome. This is how we can begin to fight these diseases of civilization and heighten our quality of life.
Note: Diet and exercise only under Doctor’s supervision, of course
References
Aiello, L. C. (1997). Brains and guts in human evolution: The Expensive Tissue Hypothesis. Brazilian Journal of Genetics,20(1). doi:10.1590/s0100-84551997000100023
Cofnas, N. (2016). Methodological problems with the test of the Paleo diet by Lamont et al. (2016). Nutrition & Diabetes,6(6). doi:10.1038/nutd.2016.22
Eaton, S. B. (2006). The ancestral human diet: what was it and should it be a paradigm for contemporary nutrition? Proceedings of the Nutrition Society,65(01), 1-6. doi:10.1079/pns2005471
Frassetto, L. A., Schloetter, M., Mietus-Synder, M., Morris, R. C., & Sebastian, A. (2009). Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. European Journal of Clinical Nutrition,63(8), 947-955. doi:10.1038/ejcn.2009.4
Galgani, J., & Ravussin, E. (2008). Energy metabolism, fuel selection and body weight regulation. International Journal of Obesity,32. doi:10.1038/ijo.2008.246
Genné-Bacon EA, Thinking evolutionarily about obesity. Yale J Biol Med 87: 99–112, 2014
Griffin, B. A. (2008). How relevant is the ratio of dietary n-6 to n-3 polyunsaturated fatty acids to cardiovascular disease risk? Evidence from the OPTILIP study. Current Opinion in Lipidology,19(1), 57-62. doi:10.1097/mol.0b013e3282f2e2a8
Harris, J. L., Bargh, J. A., & Brownell, K. D. (2009). Priming effects of television food advertising on eating behavior. Health Psychology,28(4), 404-413. doi:10.1037/a0014399
Klonoff, D. C. (2009). The Beneficial Effects of a Paleolithic Diet on Type 2 Diabetes and other Risk Factors for Cardiovascular Disease. Journal of Diabetes Science and Technology,3(6), 1229-1232. doi:10.1177/193229680900300601
Kris-Etherton PM, Taylor DS, Yu-Poth S, et al. Polyunsaturated fatty acids in the food chain in the United States. Am J Clin Nutr, 2000, vol. 71 suppl(pg. 179S-88S)
Lamont, B. J., Waters, M. F., & Andrikopoulos, S. (2016). A low-carbohydrate high-fat diet increases weight gain and does not improve glucose tolerance, insulin secretion or β-cell mass in NZO mice. Nutrition & Diabetes,6(2). doi:10.1038/nutd.2016.
Lands, B. (2015). Choosing foods to balance competing n-3 and n-6 HUFA and their actions. Ocl,23(1). doi:10.1051/ocl/2015017
Lassek, W. D., & Gaulin, S. J. (2011). Sex Differences in the Relationship of Dietary Fatty Acids to Cognitive Measures in American Children. Frontiers in Evolutionary Neuroscience,3. doi:10.3389/fnevo.2011.00005
Massiera, F., Barbry, P., Guesnet, P., Joly, A., Luquet, S., Moreilhon-Brest, C., . . . Ailhaud, G. (2010). A Western-like fat diet is sufficient to induce a gradual enhancement in fat mass over generations. The Journal of Lipid Research,51(8), 2352-2361. doi:10.1194/jlr.m006866
Mattson, M. P., Allison, D. B., Fontana, L., Harvie, M., Longo, V. D., Malaisse, W. J., . . . Panda, S. (2014). Meal frequency and timing in health and disease. Proceedings of the National Academy of Sciences,111(47), 16647-16653. doi:10.1073/pnas.1413965111
O’dea, K. (1984). Marked improvement in carbohydrate and lipid metabolism in diabetic Australian aborigines after temporary reversion to traditional lifestyle. Diabetes,33(6), 596-603. doi:10.2337/diabetes.33.6.596
Ofei F. Obesity- a preventable disease. Ghana Med J 2005;39: 98-101
Richards, M. P. (2002). A brief review of the archaeological evidence for Palaeolithic and Neolithic subsistence. European Journal of Clinical Nutrition,56(12), 1270-1278. doi:10.1038/sj.ejcn.1601646
Southam, L., Soranzo, N., Montgomery, S. B., Frayling, T. M., Mccarthy, M. I., Barroso, I., & Zeggini, E. (2009). Is the thrifty genotype hypothesis supported by evidence based on confirmed type 2 diabetes- and obesity-susceptibility variants? Diabetologia,52(9), 1846-1851. doi:10.1007/s00125-009-1419-3
Speakman, J. R. (2013). Evolutionary Perspectives on the Obesity Epidemic: Adaptive, Maladaptive, and Neutral Viewpoints. Annual Review of Nutrition,33(1), 289-317. doi:10.1146/annurev-nutr-071811-150711
Exercise, Longetivity, and Cognitive Ability
1650 words
The relationship between exercise and cognitive ability is important, but often not spoken about. Exercise releases many endorphins (Harber and Sutton, 1984) that help to further positive mood, have one better handle stress since sensitivity to stress is reduced after exercise; and after exercise, depression, and anxiety also decrease (Salmon, 2001). Clearly, if you’re attempting to maximize your cognition, you want to exercise. However, a majority of Americans don’t exercise (49 percent of Americans over the age of 18 do aerobic exercise whereas only 20 percent of Americans do both aerobic and muscle-strengthening exercise). The fact that we do not exercise as a country is proof enough that our life expectancy is declining (Olshansky et al, 2005), and we need to exercise—as a country—to reverse the trend.
Regular readers may know of my coverage of obesity on this blog. Understandably, a super majority of people will disregard my views on obesity and its causes as ‘pseudoscience’ or ‘SJW-ness’, that however says nothing to the data (and if anyone would like to discuss this, they can comment on the relevant articles). Since the average American hardly gets any exercise, this can lead to a decrease in cognitive functioning as less blood flows to the brain. Thus, everyone—especially the obese—needs to exercise to reach maximum genetic brain performance, lest they degenerate in cognitive function due a low-quality diet, such as a diet high in n-6 (the SAD diet), which is correlated with decreased cognition. Further, contrary to popular belief, the obese have lower IQs since around age three; obesity does not itself lower genotypic IQ, their IQ is ALREADY LOW which leads to obesity later in life due to a non-ability to delay gratification. Clearly, exercise education needs to be targeted at those with lower IQs since they have a higher chance of becoming obese in comparison to those with lower IQs (Kanazawa, 2013; 2014).
Clearly not eating well and not exercising can have negative effects on cognition. But what are the positives?
As mentioned previously, exercise releases endorphins that cause good mood and block pain. However, the importance of exercise does not stop there. Exercise also leads to faster reaction times on memory tasks and “increased levels of high-arousal positive affect (HAP) and decreased levels of low-arousal positive affect (LAP).” Exercise has important effects on people of all age groups (Hogan, Mata and Carstensen, 2013; Chodzko-Zajko et al, 2009). Further, physical exercise protects against age-related diseases and cognitive decline in the elderly by modifying “metabolic, structural, and functional dimensions of the brain that preserve cognitive performance in older adults.” (Kirk-Sanchez and McGough, 2014). Exercise is, clearly, a brain protectant during both adolsence and old age, so no matter your age if you want a high QoL living the best life possible, you need to supplement an already healthy lifestyle with strength training/cardio (of course, under doctor’s supervision).
Another important benefit to exercise is that it increases blood flow to the brain (Querido and Steele, 2007; Willie and Ainslie, 2011); however, changes in cerebral blood flow (CBF) during exercise are not associated with higher cognition (Ogoh et al, 2014). During prolonged exercise, cognition was improved when blood flow to the middle cerebral artery (MCA) was decreased. Thusly, exercise-induced changes in CBF do not preserve cognitive performance. Exercise to get blood to the brain is imperative for proper brain functioning. Our brains are vampiric, so we need to ‘feed it’ with blood and what’s the best way to ‘feed’ the brain in this context? Exercise!
Exercise also protects against cognitive degeneration in the elderly (Bherer, Erikson and Lie-Ambrose, 2013; Carvalho et al, 2014; Paillard, 2015). Further, longitudinal studies show an association between exercise and a decrease in dementia (Blondell, Hammersley-Mather and Veerman, 2014). The evidence is currently piling up showing that exercise at all ages is good cognitively, reduces mortality as well as a whole slew of other age-related cognitive diseases. The positive benefits of exercise need to be shown to elderly populations since exercise—mainly strength training—reduces the chance of osteoporosis (Layne and Nelson, 1999; Gray, Brezzo, and Fort, 2013). Moreover, elderly people who exercise live longer (Gremeaux et al, 2012). Now, if you don’t exercise, now’s looking like a pretty good time to start, right?
Finally, lack of exercise causes a myriad of deleterious diseases (Booth, Roberts, and Laye, 2014). This is due, in large part to our evolutionary novel environment (Kanazawa, 2004) which leads to evolutionary mismatches. An evolutionary mismatch, in this instance, is our obesogenic environment (Lake and Townshend, 2006). In terms of our current environment, it is evolutionary novel in comparison to our ancestral land (the Savanna; re: Kanazawa, 2004). Modern-day society is ‘evolutionarily novel’. In this case, we haven’t fully adapted (genetically) to our new lifestyles as, Gould said in Full House, our rate of cultural change has vastly exceeded Darwinian selection. Thusly, our environments that we have made for ourselves (and that we assume that heighten our QoL) actually cause the reverse, all the while top researchers are scratching their heads to figure out the answer, the problem while it’s staring them right in the face.
Our obesogenic environments have literally created a mismatch with our current eating habits and our ancestral one (Krebs, 2009). Moreover, dietary mismatches occur when cultural and technological change vastly outstrip biological evolution (Logan and Jacka, 2009). Clearly, we need to lessen the impact of our obesogenic environment we have made for ourselves so that we can live as long as possible, as well as be as cognitively sharp as possible. Thusly, if our environment causes a mismatch with our genome which in turn causes obesity, then by changing our environment to one that matches our genome, so to speak, levels of obesity should decline as our environment becomes less obesogenic while becoming like our ancestral environment (Genne-Bacon, 2014).
In sum, the evidence for the positive benefits for exercise is ever-mounting (not like you need Pubmed studies to know that exercise is beneficial). However, due to our obesogenic environments, this makes it hard for people with higher time preference to resist their urges and the result is what you see around you today. The evidence is clear: exercise leads to increased blood flow to our vampiric brains; thus it will have positive effects on memory and other cognitive faculties. So, in order to live to a ripe, old age as a healthy man/woman, hit the gym and treadmill and try staying away from evolutionarily novel things as much as possible (i.e., like processed food). When we, as a country recognize this, we can then be smarter, healthier and, above all else, have a high QoL while living a longer life. Is that not what we all want? Well hit the gym, start exercising and change your diet to one that matches our ancestors. Don’t be that guy/gal (we all know who that guy is) that jumps on the exercise train late and misses out on these cognitive and lifestyle benefits!
Note: Only with Doctor supervision, of course
References
Bherer, L., Erickson, K. I., & Liu-Ambrose, T. (2013). A Review of the Effects of Physical Activity and Exercise on Cognitive and Brain Functions in Older Adults. Journal of Aging Research,2013, 1-8. doi:10.1155/2013/657508
Blondell, S. J., Hammersley-Mather, R., & Veerman, J. L. (2014). Does physical activity prevent cognitive decline and dementia?: A systematic review and meta-analysis of longitudinal studies. BMC Public Health,14(1). doi:10.1186/1471-2458-14-510
Booth, F. W., Roberts, C. K., & Laye, M. J. (2013). Lack of Exercise Is a Major Cause of Chronic Diseases. Comprehensive Physiology. doi:10.1002/cphy.c110025
Carvalho, A., Cusack, B., Rea, I. M., & Parimon, T.,. (2014). Physical activity and cognitive function in individuals over 60 years of age: a systematic review. Clinical Interventions in Aging, 661. doi:10.2147/cia.s55520
Chodzko-Zajko WJ, Proctor DN, Fiatarone Singh MA, Minson CT, Nigg CR, Salem GJ, Skinner JS: American College of Sports Medicine position stand. Exercise and physical activity for older adults. Med Sci Sports Exerc. 2009, 41: 1510-1530. 10.1249/MSS.0b013e3181a0c95c.
Gray M., Di Brezzo R., I.L. Fort (2013) The effects of power and strength training on bone mineral density in premenopausal women. J Sports Med Phys Fitness, 53, pp. 428–436
Genné-Bacon EA, Thinking evolutionarily about obesity. Yale J Biol Med 87: 99–112, 2014
Gremeaux V, Gayda M, Lepers R, Sosner P, Juneau M, Nigam A. Exercise and longevity. Maturitas. 2012;73(4):312–7.
Harber VJ, Sutton JR. (1984) Endorphins and exercise. Sports Medicine 1: 154–174, 1984
Hogan, C. L., Mata, J., & Carstensen, L. L. (2013). Exercise holds immediate benefits for affect and cognition in younger and older adults. Psychology and Aging,28(2), 587-594. doi:10.1037/a0032634
Kanazawa, S. (2004). The Savanna Principle. Managerial and Decision Economics,25(1), 41-54. doi:10.1002/mde.1130
Kanazawa, S. (2013). Childhood intelligence and adult obesity. Obesity,21(3), 434-440. doi:10.1002/oby.20018
Kanazawa, S. (2014). Intelligence and obesity. Current Opinion in Endocrinology & Diabetes and Obesity,21(5), 339-344. doi:10.1097/med.0000000000000091
Krebs, J. R. (2009). The gourmet ape: evolution and human food preferences. American Journal of Clinical Nutrition,90(3). doi:10.3945/ajcn.2009.27462b
Lake, A., & Townshend, T. (2006). Obesogenic environments: exploring the built and food environments. The Journal of the Royal Society for the Promotion of Health,126(6), 262-267. doi:10.1177/1466424006070487
Layne, J. E., & Nelson, M. E. (1999). The effects of progressive resistance training on bone density: a review. Medicine & Science in Sports & Exercise,31(1), 25-30. doi:10.1097/00005768-199901000-00006
Kirk-Sanchez, N., & Mcgough, E. (2014). Physical exercise and cognitive performance in the elderly: current perspectives. Clinical Interventions in Aging, 51. doi:10.2147/cia.s39506
Ogoh, S., Tsukamoto, H., Hirasawa, A., Hasegawa, H., Hirose, N., & Hashimoto, T. (2014). The effect of changes in cerebral blood flow on cognitive function during exercise. Physiological Reports,2(9). doi:10.14814/phy2.12163
Olshansky, S. J., Passaro, D. J., Hershow, R. C., Layden, J., Carnes, B. A., Brody, J., . . . Ludwig, D. S. (2005). A Potential Decline in Life Expectancy in the United States in the 21st Century. New England Journal of Medicine,352(11), 1138-1145. doi:10.1056/nejmsr043743
Paillard, T. (2015). Preventive effects of regular physical exercise against cognitive decline and the risk of dementia with age advancement. Sports Medicine – Open,1(1). doi:10.1186/s40798-015-0016-x
Querido, J. S., & Sheel, A. W. (2007). Regulation of Cerebral Blood Flow During Exercise. Sports Medicine,37(9), 765-782. doi:10.2165/00007256-200737090-00002
Salmon, P. (2001). Effects of physical exercise on anxiety, depression, and sensitivity to stress. Clinical Psychology Review,21(1), 33-61. doi:10.1016/s0272-7358(99)00032-x
Willie, C. K., & Ainslie, P. N. (2011). Cool head, hot brain: cerebral blood flow distribution during exercise. The Journal of Physiology,589(11), 2657-2658. doi:10.1113/jphysiol.2011.209668
NotPoliticallyCorrect 