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.
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.
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.
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.