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Evolutionary Psychology Does Not Explain Differences Between Rightists and Leftists

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Unless you’ve been living under a rock since the new year, you have heard of the “coup attempt” at the Capitol building on Wednesday, January 6th. Upset at the fact that the election was “stolen” from Trump, his supporters showed up at the building and rushed it, causing mass chaos. But, why did they do this? Why the violence when they did not get their way in a fair election? Well, Michael Ryan, author of The Genetics of Political Behavior: How Evolutionary Psychology Explains Ideology (2020) has the answer—what he terms “rightists” and “leftists” evolved at two different times in our evolutionary history which, then, explains the trait differences between the two political parties. This article will review part of the book—the evolutionary sections (chapters 1-3).

EP and ideology

Explaining why individuals who call themselves “rightists and leftists” behave and act differently than the other is Ryan’s goal. He argues, at length, that the two parties have two different personality profiles. This, he claims, is due to the fact that the ancestors of rightists and leftists evolved at two different times in human history. He calls this “Trump Island” and “Obama Island”—apt names, especially due to what occurred last week. Ryan claims that what makes Trump different from, say, Obama, is that his ancestors evolved at a different place in a different time compared to Obama’s ancestors. He further claims using the Stanford Prison Experiment that “we may not all be capable of becoming Nazis, after all. Just some, and conservatives especially so” (pg 12).

In the first chapter he begins with the usual adaptationism that Evolutionary Psychologists use. Reading between the lines in his implicit claims, he is arguing that “rightists and leftists” are natural kinds—that is, they are *two different kinds of people.* He explains some personality differences between rightists and leftists and then says that such trait differences are “rooted in biology and governed by genes” (pg 17). Ryan then makes a strong adaptationist claim—that traits are due to adaptation to the environment (pg 17). What makes you and I different from Trump, he claims, is that our ancestors and his ancestors evolved in different places at different times where different traits would be imperative to survival. So, over time, different traits got selected-for in these two populations leading to the trait differences we see today. So each environment led to the fixation of different adaptive traits which explains the differences we see today between the two parties, he claims.

Ryan then shifts from the evolution of personality differences to… The evolution of the beaks of Darwin’s finches and Tibetan adaptation to high-altitude living (pg 18), as if the evolution of physical traits is anything like the evolution of psychological traits. His folly is assuming that these physical traits can then be likened to personality/mental traits. The ancestors of rightists and leftists, like Darwin’s finches Ryan claims, evolved on different islands in different moments of evolutionary time. They evolved different brains and different adaptive behaviors on the basis of the evolution of those different brains. Trump’s ancestors were authoritarian, and this island occurred early in human history “which accounts for why Trump’s behavior seems so archaic at times” (pg 18).

The different traits that leftists show in comparison to rightists is due to the fact that their island came at a different point in evolutionary time—it was not recent in comparison to the so-called archaic dominance behavior portrayed by Trump and other rightists. Ryan says that Obama Island was more crowded than Trump Island where, instead of scowling, they smiled which “forges links with others and fosters reciprocity” (pg 19). So due to environmental adversity, they had a more densely populated “island”—in this novel situation, compared to the more “archaic” earlier time—the small bands needed to cooperate, rather than fight with each other, to survive. So this, according to Ryan, explains why studies show more smiling behavior in leftists compared to rightists.

Some of our ancestors evolved traits such as cooperativeness the aided the survival of all even though not everyone acquired the trait … Eventually a new genotype or subpopulation emerged. Leftist traits became a permanent feature of our genome—in some at least. (pg 19-20)

So the argument goes: Differences between rightists and leftists show us that the two did not evolve at the same points in time since they show different traits today. Different traits were adaptive at different points in time, some more archaic, some more modern. Since Trump Island came first in our evolutionary history, those whose ancestors evolved there show more archaic behavior. Since Obama Island came first, they show newer, more modern behaviors. Due to environmental uncertainty, those on Obama Island had to cooperate with each other. The trait differences between these two subpopulations were selected for in their environment that they evolved in, which is why they are different today. Now today, this led to the “arguing over the future direction of our species. This is the origin of human politics” (pg 20).

Models of evolution

Ryan then discusses four models of evolution: (1) the standard model, where “natural selection” is the main driver of evolutionary change; (2) epigenetic models like Jablonka’s and Lamb’s (2005) in Evolution in Four Dimensions; (3) where behavioral changes change genes; and (4) where organisms have phenotypic plasticity and is a way for the organism to respond to sudden environmental changes. “Leftists and rightists“, writes Ryan, “are distinguished by their own versions of phenotypic plasticity. They change behavior more readily than rightists in response to changing environmental signals” (pg 29-30).

In perhaps the most outlandish part of the book, Ryan articulates one of my now-favorite just-so stories. The passage is worth quoting in-full:

Our direct ancestor Homo erectus endured for two million years before going extinct 400,000 years ago when earth temperatures dropped far below the norm. Descendants of erectus survived till as recently as 14,000 years ago in Asia. The round head and shovel-shaped teeth of some Asians, including Vladimir Putin, are an erectile legacy. Archeologists believe erectus was a mix of Ted Bundy and Adolf Hitler. Surviving skulls point to a life of constant violence and routine killing. Erectile skulls are thick like a turtle’s, and the brow’s are ridged for protection from potentially fatal blows. Erectus’ life was precarious and violent. To survive, it had to evolve traits such as vigilant fearfulness, prejudice against outsiders, bonding with kin allies, callousness toward victims, and a penchant for inflexible habits of life that were known to guarantee safety. It had to be conservative. 34 Archeologists suggest that some of our most characteristic conservative emotions such as nationalism and xenophobia were forged at the time of Homo erectus. 35 (pg 33-34)

It is clear that Ryan is arguing that rightists have more erectus-like traits whereas leftists have more modern, Sapiens traits. “The contemporary coexistence of a population with more “modern” traits and a population with more “archaic” traits came into being” (pg 37). He is implicitly assuming that the two “populations” he discusses are natural kinds and with his “modern” “archaic” distinction (see Crisp and Cook 2005 who argue against a form of this distinction) he is also implying that there is a sort of “progress” to evolution.

Twin studies, it is claimed, show “one’s genetically informed psychological disposition” (Hatemi et al, 2014); they “suggest that leftists and rightists are born not made” while a so-called “consensus has emerged amongst scientists: political behavior is genetically controlled and heritable” (pg 43). But, Beckway and Morris (2008), Charney (2008), and Joseph (2009; 2013) argue that twin studies can do no such thing due to the violation of the equal environments assumption (Joseph, 2014; Joseph et al, 2015). Thus, Ryan’s claims of the “genetic origins” of political behavior rest on studies that cannot prove or disprove “genetic causation” (Shulitziner, 2017)—but since the EEA is false we must discount “genetic causation” for psychological traits, not least because it is impossible for genes to cause/influence psychological traits (see argument (iii)).

The arguments he provides are a form of inference to best explanation (IBE) (Smith, 2016). However, this is how just-so stories are created: the conclusion is already in mind, and then the story is crafted using “natural selection” to explain how a trait came to fixation and why it currently exists today. The whole book is full of such adaptive stories. Claiming that we have the current traits we do in the distributions they are in in the “populations” because they were, at a certain point in our evolutionary history, adaptive which then led to the individuals with those traits passing on more of their genes, eventually leading to trait fixation. (See Fodor and Piattelli-Palmarini, 2010).

Ryan makes such outlandish claims such as “Rightists are more likely than leftists to keep their desks neat. If in the distant past you knew exactly where the weapons were, you could find them quickly and react to danger more effectively. 26” (pg 45). He talks about how “time-consuming and effort-demanding accuracy of perception [were] more characteristic of leftist cognitionleftist cognition is more reflective” while “rightist cognition is intuitive rather than reflective” (pg 47). Rightists being more likely to endorse the status quo, he claims, is “an adaptive trait when scarce resources made energy management essential to getting by” (pg 48) Rightist language, he argues, uses more nouns since they are “more concrete, an anxious personalities prefer concrete to abstract language because it favors categorial rigidity and guarantees greater certainty” while leftists “use words that suggest anxiety, anger, threats, certainty, resistance to change, power, security, and conformity” (pg 49). There is “a connection between archaic physiology and rightist moral ideology” (pg 52). Certain traits that leftists have were “adaptive traits [that] were suited to later stage human evolution” (pg 53). Ryan just cites studies that show differences between rightists and leftists and then uses some great leaps and mental gymnastics to try to mold the findings as being due to evolution in the two different time periods he describes in chapter 1 (Trump and Obama Island).


I have not read one page in this book that does not have some kind of adaptive just-so story attempting to explain certain traits/behaviors between rightists and leftists in evolutionary terms. Ryan uses the same kind of “reasoning” that Evolutionary Psychologists use—have your conclusion in mind first and then craft an adaptive story to explain why the traits you see today are there. Ryan outright says that “[t]raits are the result of adaptation to the environment” (pg 17), which is a rare—strong adaptationist—claim to make.

His book ticks off all of the usual EP things: strong adaptationism, just-so storytelling, the claim that traits were selected-for due to their contribution in certain environments at different points in time. The strong adaptationist claims, for example, are where he says that erectus’ large brow “are rigid for protection from potentially fatal blows” (pg 34). Such strong adaptationist claims imply that Ryan believes that all traits are the result of adaptation and that they, as a result, are still here today because they all serve a function in our evolutionary past. His arguments are, for the most part, all evolutionary and follow the same kinds of patterns that the usual EP arguments do (see Smith, 2016 for an explication of just-so stories and what constitutes them). Due to the problems with evolutionary psychology, his adaptive claims should be ignored.

The arguments that Ryan provides are not scientific and, although they give off a veneer of being scientific by invoking “natural selection” and adaptationism, they are anything but. It is just a long-winded explanation for how and why rightists and leftists—liberals and conservatives—are different and why they cannot change, since these differences are “encoded” into our genome. The implicit claim of the book, then, that rightists and leftists are two different—natural—kinds, lies on the false bed of EP and, therefore, the arguments provided in the book fail to sway anyone that does not believe such fantastic storytelling masquerading as science. While he does discuss other evolutionary theories, such as epigenetic ones from Jablonka and Lamb (2005), the book is largely strongly adaptationist using “natural selection” to explain why we still have the traits we do in different “populations” today.

Rampant Adaptationism

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Adaptationism is the main school of evolutionary change, through “natural selection” (NS). That is the only way for adaptations to appear, says the adaptationist: traits that were conducive to reproductive success in past environments were selected-for their contribution to fitness and therefore became fixated in the organism in question. That’s adaptationism in a nutshell. It’s also vacuous and tells us nothing interesting. In any case, the school of thought called adaptationism has been the subject of much criticism, most importantly, Gould and Lewontin (1972), Fodor (2008) and Fodor and Piatteli-Palmarini (2010). So, I would say that adaptationism becomes “rampant” when clearly cultural changes are conflated as having an evolutionary history and are still around today due to being adaptations.

Take Bret Weinstein’s recent conversation with Richard Dawkins:

Weinstein: “Understood through the perspective of German genes, vile as these behaviors were, they were completely comprehensible at the level of fitness. It was abhorrent and unacceptable—but understandable—that Germany should have viewed its Jewish population as a source of resources if you viewed Jews as non-people. And the belief structures that cause people to step onto the battlefields and fight were clearly comprehensible as adaptations of the lineages in question.”

Dawkins: “I think nationalism may be an even greater evil than religion. And I’m not sure that it’s actually helpful to speak of it in Darwinian terms.”

I find it funny that Weinstein is more of a Dawkins-ist than Dawkins himself is (in regard to his “selfish gene theory”, see Noble, 2011). In any case, what a ridiculous claim. “Guys, the Nazis were bad because of their genes and their genes made them view Jews as non-people and resources. Their behaviors were completely understandable at the level of fitness. But, Nazis bad!”

What a ridiculous claim. I like how Dawkins quickly shot the bullshit down. This is just-so storytelling on steroids. I wonder what “belief structures that cause people to step onto battlefields” are “adaptations of the lineages in question”? Do German belief structure adaptations different from any other groups? Can one prove that there are “belief structures” that are “adaptations to the lineages in question”? Or is Weinstein just telling just-so stories—stories with little evidence and that “fit” and “make sense” with the data we have (despicable Nazi behavior towards Jews after WWI and before and during WWII).

There is a larger problem with adaptationism, though: adaptationist confuse adaptiveness with adaptation (a trait can be adaptive without being an adaptation), they overlook nonadaptationist explanations, and adaptationist hypotheses are hard to falsify since a new story can be erected to explain the feature in question if one story gets disproved. That’s the dodginess of adaptationism.

An adaptationist may look at an organism, look at its traits, then construct a story as to why they have the traits they do. They will attempt to think of its evolutionary history by thinking of the environment it is currently in and what the traits in question that it has are useful for now. But there is a danger here. We can create many stories for just one so-called adaptation. How do we distinguish between which stories explain the fixation of the trait and which do not? We can’t: there is no way for us to know which of the causal stories explains the fixation of the trait.

Gould and Lewontin (1972) fault:

the adaptationist programme for its failure to distinguish current utility from reasons for origin (male tyrannosaurs may have used their diminutive front legs to titillate female partners, but this will not explain why they got so small); for its unwillingness to consider alternatives to adaptive stories; for its reliance upon plausibility alone as a criterion for accepting speculative tales; and for its failure to consider adequately such competing themes as random fixation of alleles, production of nonadaptive structures by developmental correlation with selected features (allometry, pleiotropy, material compensation, mechanically forced correlation), the separability of adaptation and selection, multiple adaptive peaks, and current utility as an epiphenomenon of nonadaptive structures.


One must not confuse the fact that a structure is used in some way (consider again the spandrels, ceiling spaces, and Aztec bodies) with the primary evolutionary reason for its existence and conformation.

Of course, though, adaptationists (e.g., evolutionary psychologists) do confuse structure for function. This is fallacious reasoning. That a trait is useful in a current environment is in no way evidence that it is an adaptation nor is it evidence that that’s why the trait evolved (e.g., a trait being useful and adaptive in a current environment).

But there is a problem with looking to the ecology of the organism in question and attempting to construct historical narratives about the evolution of the so-called adaptation. As Fodor and Piatteli-Palmarini (2010) note, “if evolutionary problems are individuated post hoc, it’s hardly surprising that phenotypes are so good at solving them.” So of course if an organism fails to secure a niche then that means that the niche was not for that organism.

That organisms are so “fit” to their environment, like a puzzle piece to its surrounding pieces, is supposed to prove that “traits are selected-for their contribution to fitness in a given ecology”, and this is what the theory of natural selection attempts to explain. Organisms fit their ecologies because its their ecologies that “design” their traits. So it is no wonder that organisms and their environments have such a tight relationship.

Take it from Fodor and Piatelli-Palmarini (2010: 137):

You don’t, after all, need an adaptationist account of evolution in order to explain the fact that phenotypes are so often appropriate to ecologies, since, first impressions to the contrary notwithstanding, there is no such fact. It is just a tautology (if it isn’t dead) a creature’s phenotype is appropriate for its survival in the ecology that it inhabits.

So since the terms “ecology” and “phenotype” are interdefined, is it any wonder why an organism’s phenotype has such a “great fit” with its ecology? I don’t think it is. Fodor and Piatteli-Palmarini (2010) note how:

it is interesting and false that creatures are well adapted to their environments; on the other hand it’s true but not interesting that creatures are well adapted to their ecologies. What, them, is the interesting truth about the fitness of phenotypes that we require adaptationism in order to explain? We’ve tried and tried, but we haven’t been able to think of one.

So the argument here could be:

P1) Niches are individuated post hoc by reference to the phenotypes that live in said niche.
P2) If the organisms weren’t there, the niche would not be there either.
C) Therefore there is no fitness of phenotypes to lifestyles that explain said adaptation.

Fodor and Piatteli-Palmarini put it bluntly about how the organism “fits” to its ecology: “although it’s very often cited in defence of Darwinism, the ‘exquisite fit’ of phenotypes to their niches is either true but tautological or irrelevant to questions about how phenotypes evolve. In either case, it provides no evidence for adaptationism.”

The million-dollar question is this, though: what would be evidence that a trait is an adaptation? Knowing what we now know about the so-called fit to the ecology, how can we say that a trait is an adaptation for problem X when niches are individuated post hoc? That right there is the folly of adaptationism, along with the fact that it is unfalsifiable and leads to just-so storytelling (Smith, 2016).

Such stories are “plausible”, but that is only because they are selected to be so. When such adaptationism becomes entrenched in thought, many traits are looked at as adaptations and then stories are constructed as to how and why the trait became fixated in the organism. But, just like EP which uses the theory of natural selection as its basis, so too does adaptationism fail. Nevermind the problem of the fitting of species to ecologies to render evolutionary problems post hoc; nevermind the problem that there is no identifying criteria for identifying adaptations; do mind the fact that there is no possible way for natural selection to do what it does: distinguish between coextensive traits.

In sum, adaptationism is a failed paradigm and we need to dispense with it. The logical problems with it are more than enough to disregard it. Sure, the fitness of a phenotype, say, the claws of a mole do make sense in the ecology it is in. But we only claim that the claws of a mole are adaptations after the fact, obviously. One may say “It’s obvious that the claws of a mole are adaptations, look at how it lives!” But this betrays a notion that Gould and Lewontin (1972) made: do not confuse structure with an evolutionary reason for its existence, which, unfortunately, many people do (most glaringly, evolutionary psychologists). Weinstein’s ridiculous claims about Nazi actions during WWII are a great example of how rampant adaptationism has become: we can explain any and all traits as an adaptation, we just need to be creative with the stories we tell. But just because we can create a story that “makes sense” and explains the observation does not mean that the story is a likely explanation for the trait’s existence.

JP Rushton, Richard Lynn, Satoshi Kanazawa, and Michael Hart: the Just-so Storytellers

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The four men in the title are, in my opinion, the biggest just-so storytellers in the “HBD” movement. These four men have written numerous journal articles and books pushing their just-so stories—making a career out of storytelling. We have Rudyard Kipling’s Just So Stories for Little Children, well Rushton, Lynn, Kanazawa, and Hart (RLKH) told Just-so Stories for Adults—like all EP is. Either way, RLKH have quite the following—those who would defend their just-so stories—and if you deny and question them, you’re “denying evolution” and are “no better than a creationist.” Well, too bad for them, rejecting just-so stories means nothing of the sort.

So even though humans as a species are incredibly K selected, some believe that some humans are more K selected than others.  In other words, while some men have numerous sexual partners and father lots of illegitimate babies with different mothers, other men are more nerdy, and father very few children with only one woman, but they make sure those children are well parented and provided for.

When men first evolved in the warm hospitable tropics some 200,000 years ago, survival was relatively easy, so instead of natural selection (survival of the fittest), genetic fitness was determined by who could get the most women (sexual selection).  As a result, men with the biggest muscles, highest testosterone, best social skills, most charisma and sexual abilities, were the most successful at passing on their genes.  But as the ice age emerged and humans moved North, passing on genes became more about natural selection and less about sexual selection.  What good is it to be a great pick up artist if you can’t survive the winter long enough to mate? (PumpkinPerson; Why women hate nerdy men)

When asked “why white women didn’t evolve to prefer nerds,” PumpkinPerson writes that “cold climate women evolved to be submissive so their preferences were prehistorically irrelevant.” More and more just-so stories. That’s all “HBD” is: a collection of just-so stories.

Sexual selection is a subset of “natural selection” but there is one important difference: humans have minds and thus, humans can *attempt to* “select-for” traits, but each trait is coextensive with an infinitude of traits which throws a wrench in the notion. There is no such thing as “natural selection (Fodor and Piatteli-Palmarini, 2010).

The above just-so story, personally, is one of my favorites, in the top ten, at least. This type of just-so story was popularized by Rushton and his r/K selection theory (read the rebuttal here; I also have many rebuttals of Anonymous Conservatives just-so stories, his attempted revival of Rushton’s storytelling). Africans, like PP claimed above, evolved in hotter, harsher environments, and so had to have more progeny in order to ensure reproductive success. On the other hand, when Man out of Africa, he encountered colder temperatures and, it is said, had to have fewer children in order to ensure that the children were looked after.

According to Richard Lynn, then, this migration into colder climates caused a decrease in colder climates due to a shift to “K strategy”, which then “selected-for” lower testosterone (Lynn, 1990). In Lynn (1990), he claims that differences in PCa (prostate cancer) are evidence for the claim that blacks have higher levels of testosterone than whites, which drives behavioral differences between the races. He then assumes that these differences have an evolutionary origin between the races, and that migrating into colder climates caused a decrease in testosterone in Europeans compared to Africans. However, one large mistake that Lynn (1990) makes is assuming that testosterone levels today have any bearing on testosterone levels thousands of years ago.

Claims that PCa are caused by higher levels of testosterone are ubiquitous in the “HBD” literature. But, as I have covered in the past, there is no reason to be scared of the hormone testosterone (read my most extensive review here); testosterone does not cause aggression and it does not cause PCa (Stattin et al, 2003).

One of the most oft-cited studies on the matter of T differences between blacks and whites is a small, highly methodologically/conceptually flawed study by Ross et al (1986). I have documented numerous flaws with the study.

So Lynn, in his 1990 just-so story shown above, claims that, due to colder temperatures, children would have needed more attention. Giving more attention would have meant having fewer children. This was done, he claims, through shifting to K strategy. So then, a decrease in testosterone was how to achieve this “K adaptation”, and achieving this “K adaptation” was through a reduction in T levels which subsequently, according to Lynn, brought “about a lowering of sexual drive and behaviour” (Lynn, 1990: 1205).

Note how Lynn’s claims in this paper *completely rest on* differences in prostate cancer between races. He uses these differences due to the assumption that high levels of testosterone contribute to differences in prostate cancer. This claim is false.

One of my favorites is from Rushton and Templer (2012) who attempt to show that the melanocortin system modulates aggression and sexuality in humans. I wrote a response to it, and, of course, one of the main culprits is our old friend testosterone. The hypothesis put forth is, of course, another just-so story. Nevermind the fact that Rushton and Templer show no understanding of endocrinology. We have a great understanding of the melanocortin system and what it does in humans (see Cone, 2006), but, unfortunately for Rushton and Templer, none of the review discusses the fringe ideas they put forth. Rushton and Templer showed that they do not understand human physiology, much less the melanocortin system.

Lynn (2013) even claims that testosterone has an effect on human penis length between races, citing a study on… rats. RATS!! THAT is the standard of evidence that Lynn has for attempting to prove his fringe just-so stories.

These just-so stories pushed by Rushton (1997), Lynn (2006), and Hart (2007) lack independent evidence—we don’t have a time machine to verify their claims. So they’re just-so stories. I rebutted all 3 of these psycho-logists’ claims in this article on how black women do not have higher levels of T than white women. I did, indeed, used to push all types of just-so stories when I was a more hard-core “HBDer”, but I’ve since learned the errors of my ways and have stopped telling just-so stories See exhibit A, defending Kanazawa’s just-so stories.

I wrote:

“To be blunt, black women look more like men than women due to their higher levels of testosterone.”

I can’t believe some of the stuff that I used to write/believe… I have, of course, since seen the error of my ways (in more than one way, as can be evidenced by my view changes over the past two years).

Anyway, these types of claims are easily put to rest by reading Mazur’s (2016) analysis of testosterone and honor culture.

“There is no indication of inordinately high T among young black women with low education.”

“The pattern [high testosterone] is not seen among teenage boys or among females.”

So, quite clearly, PumpkinPerson’s just-so storytelling, as popularized by RLKH, has no backing in reality—these psycho-logists told nothing but just-so stories. “But the stories are consistent with the data!”, one may attempt to say. Well, to that, I would say the stories are selected to be consistent with the data; how parsimonious a just-so story is with any current data is irrelevant since one can spin any type of story they want to fit with any data point they have. This is put succinctly by Smith (2016) in his paper Explanations for adaptations, just-so stories, and limitations on evidence in evolutionary biology:

“An important weakness in the use of narratives for scientific purposes is that the ending is known before the narrative is constructed. … [Just-so stories] are always consistent with the observations because they are selected to be so.”

The method known as “inference to best explanation” is not a solution to these problems. … Some just-so stories should not be told.

Now, put this to the stories of RLKH, and it will become clear that all they are doing is storytelling—telling just-so stories for adults. These types of stories are inherently ad hoc and generate no testable predictions. It doesn’t matter that they “agree with the data”, since one can construct any type of narrative to agree with the data—that’s a fact.

It’s no surprise that people still, to this day, attempt to defend RLKH’s just-so storytelling—it is rooted in the Darwinian paradigm of natural selection, after all. However, appealing to an imaginary force (natural selection) which shaped traits over thousands of years is literally telling just-so stories—there is no evidence for the claim other than evidence the story purports to explain—nevermind the fact that the trait in question could have moved to fixation by other methods than “selection.” (See Samir Okasha’s (2018) book Agents and Goals in Evolution for a critique of Darwin’s view of “natural selection” with an “agent” behind it, guiding the process—Mother Nature.) Thus, RLKH et al are nothing but Darwinian just-so storytellers—and anyone who defends them as being “purveyors of truth”, people who get “shouted down” for attempting to “speak the truth” are no better than the just-so storytellers themselves.

Problems with Evolutionary Psychology

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Evolutionary Psychology (EP) is a discipline which purports to explain mental and psychological traits as adaptations—functional products of “natural selection”—which are genetically inherited/transmitted. Its main premises is that the human mind can be explained by evolution through natural selection; that the mind is “modular”—called the “massive modularity hypothesis” (see Pinker, 1997). EP purports that the mind is “a cluster of evolved information-processing mechanisms” with its main goal being “to characterize these Darwinian algorithms” (Sterelny and Griffiths, 1999: 336). The problem with EP, though, is that many of the “theories/hypotheses” are just speculation—what is termed “just-so stories” (Gould and Lewontin, 1979; Richardson, 2007; Nielsen, 2009Fodor and Piattelli-Palmarini, 2010). In this article, I will discuss the massive modularity hypothesis, adaptationism, and the promises that EP makes as a whole.

Massive Modularity

The massive modularity hypothesis (MMH) proposes that the modules “for” mental processing evolved in response to “natural selection” (Samuels, 1998). To evolutionary psychologists, the mind is made up of different modules that were “selected for” different mental abilities. So, to evolutionary psychologists like Tooby and Cosmides, Pinker et al, much of human psychology is rooted in the Pleistocene (i.e., Tooby and Cosmides’ 5th Principle that “our modern skulls house a stone age mind“) . Evolutionary psychologists propose that the mind is made up of different, genetically influenced, modules that which were specifically selected as to help our ancestors solve domain-specific problems.

Two principle arguments exist for the MMH. Argument (1)—called the optimality argument—is:

  1. There are adaptive problems in every environment; different adaptive problems in different environments require different solutions, and different solutions can be implemented by functionally distinct modules.
  2. Adaptive problems are selective pressures; for each unique pressure faced in the original evolutionary environment (OEE), there is a unique module which was selected to solve those—and only those—specific adaptive problems.
  3. Selective mechanisms can produce highly specialized cognitive modules.
  4. Therefore, since different adaptive problems require different solutions and different solutions can be implemented by functionally distinct modules, then there must exist differing modules in the human mind which were selected for in virtue of their contribution to fitness.

Or the argument could be:

  1. Domain-specific processes exist
  2. These processes arose due to evolution
  3. Therefore these domain-specific processes that arose due to evolution have a genetic basis

Tooby and Cosmides claim that, distinct modules for certain adaptive problems in distinct environments are superior at solving different problems, rather than a general-purpose cognitive module. They argue that selection can produce different modules in the mind “for” different adaptive problems. Tooby and Cosmides put their argument in their own words as:

(1) As a rule, when two adaptive problems have solutions that are incompatible or simply different, a single solution will be inferior to two specialized solutions

(2) .. . domain-specific cognitive mechanisms . . . can be expected to systematically outperform (and hence preclude or replace) more general mechanisms

(3) Simply to survive and reproduce, our Pleistocene ancestors had to be good at solving an enormously broad array of adaptive problems—problems that would defeat any modern artificial intelligence system. A small sampling include foraging for food, navigating, selecting a mate, parenting, engaging in social exchange, dealing with aggressive threat, avoiding predators, avoiding pathogenic contamination, avoiding naturally occurring plant toxins, avoiding incest and so on

(4) [Therefore] The human mind can be expected to include a large number of distinct, domain-specific mechanisms (quoted from Samuels, 1998: 585-586)

Clearly, the assumption from Tooby and Cosmides is that specific modules for certain adaptive problems in the OEE are superior to general-purpose modules. Samuels (1998: 586) writes:

In the case of psychological traits, in order to use optimality considerations with any confidence one needs to know (a) what features were being optimized by the evolutionary process and (b) what range of phenotypes were available to natural selection. As a matter of fact, however, we have little knowledge about either of these matters.

Samuels (1998) thusly concludes that “the endorsement of the Massive Modularity Hypothesis by evolutionary psychologists is both unwarranted and unmotivated.” (Also see Prinz, 2006.)

The key point of the MMH is that, according to Tooby and Cosmides, we would expect that the mind consists of different modules which are “designed” to solve domain-specific problems. If we know what type of adaptive situations happened to our ancestors then we should be able to construct the evolution of a trait by knowing its current functional use and “working backwards”—what is termed “reverse engineering”—inferring “function” from “cause” (see Richardson, 2007: chapter 2); inferring effect from relevant causes (see Richardson, 2007: chapter 3) and disentangling historical ancestry from history and structure (see Richardson, 2007: chapter 4).

As for their second argument:

  1. It is impossible for human psychology—that contains nothing but general-purpose mechanisms—to have evolved since such a system cannot be adaptive.
  2. Such a system cannot possibly have solved the adaptive problems faced by our ancestors in the evolutionary past.
  3. Therefore, the mind cannot possibly have evolved general-purpose mechanisms and had to have evolved different mental modules in order to carry out different tasks.

They defend the argument by stating that the domain-dependence of different errors is a cause of the evolution of different modules of the mind; that information for crucial adaptive behavior cannot be learned by using only domain-specific systems; and that many adaptive problems are highly complex and unlikely to have been solved by general-purpose modules. Therefore, the mind must be modular since this can account for domain-specific problems—while, according to Tooby and Cosmides, general-purposed modules cannot. The argument, though, fails to provide us with any reason to accept the claim that the mind is made up of mostly—or is all made up of—Darwinian modules which were kept around since they were targets of selection.

Clearly, evidence for the modularity of mind is lacking—as is the evidence that reverse engineering “works” for the purpose intended.

Lloyd (1999: 224) writes that:

Given these difficulties – well-known especially since Konrad Lorenz and Nico Tinbergen’s pioneering experiments on animal behavior – it is not scientifically acceptable within evolutionary biology to conclude that, because a given pattern of responses contributes to evolutionary success, then there is some ‘organ’ (or part of the brain) producing such a pattern, that is therefore an adaptation (see Williams 1966). This is because the ‘organ’ or ‘module’ may not actually exist as a biologically real trait, and even if it does, its current function may or may not be the same as the past function(s).

Sterelny and Griffiths (1999: 342) write that “… evolutionary psychology has bought into an oversimplified view of the relationship between an evolving population and its environment, and has prematurely accepted a modular conception of the mind.

False dichotomies

Tooby and Cosmides (1992) coined the phrase “Standard Social Science Model” (SSSM) in order to differentiate their EP model (the “integrated causal model”; ICM) from the SSSM. According to Tooby and Cosmides (1992), the basis of the SSSM is to employ complete general-purpose cognitive modules and to deny any type of nativist modules whatsoever. Therefore, according to Tooby and Cosmides’ characterization of their so-called “opposition”, interesting differences between groups—and, of course, individuals—are due completely to cultural conditioning with absolutely no nativist elements since there are only general-purpose modules. Differences between individuals, according to the SSSM, are cultural products—differences in socialization cause individual differences.

Richardson (2007:179) writes:

Tooby and Cosmides’ portrayal [of the SSSM] is very effective. It is also a piece of sophistry, offering a false dichotomy between a manifestly untenable view and their own. The alternative is one that sees no differences between individuals and no biological contribution to individual or social development. I think no serious figure embraces that view, since, perhaps, John Watson in the early twentieth century.

Tooby and Cosmides also say that “There is no small irony in the fact that [the[ Standard Social Science MOdel’s hostility to adaptationist approaches is often justified through the accusation that adaptationist approaches purportedly attribute important differences between individuals, races and classes to genetic differences. In actuality, adaptationist approaches offer the explanation for why the psychic unity of humankind is genuine and not just an ideological fiction” (1992, 79).

Furthermore, David Buss claims that “Natural selection is the only prospect for explaining human nature” (Richardson, 2007: 182). (Whatever “human nature” is. See Nagel’s 2012 Mind and Cosmos for arguments that the mind cannot possibly have been naturally selected since evolutionary biology is a physical theory and Fodor and Pitatelli-Palmarini’s 2010 book What Darwin Got Wrong for the argument against natural selection as an explanatory mechanism in regard to trait fixation.)

Problems with the adaptationist paradigm

Adaptationism is a research programme in which, according to the Stanford Encyclopedia of Philosophy, ““adaptationists” view natural selection among individuals within a population as the only important cause of the evolution of a trait; they also typically believe that the construction of explanations based solely on natural selection to be the most fruitful way of making progress in evolutionary biology and that this endeavor addresses the most important goal of evolutionary biology, which is to understand the evolution of adaptations.” 

Though numerous problems exist with this programme, not least the claim that most—or all—important phenotypic traits are the product of evolution by natural selection. In their book Sex and Death: An Introduction to Philosophy of Biology, Sterelny and Griffiths (1999: 351) write:

Adaptive explanation is an inference from the current phenotype of an organism to the problems that organism faced in its evolutionary past. Obviously, that inference will be problematic if we do not have an accurate description of the current phenotype and its adaptive significance—of the solution that evolution actually produced. The inference from current adaptive importance to adaptation is problematic enough even when the adaptive and phenotypic claims on which it is based are uncontroversial (13.1). The inference is still more problematic when the nature of the phenotype and its adaptive importance are yet to be established.

This is not the main problem with the paradigm, though. The main problem is that all of these theories/hypotheses are “just-so stories”—“… an adaptive scenario, a hypothesis about what a trait’s selective history might have been and hence what its function may be” (Sterelny and Griffiths, 1999: 61). I’d also add that just-so stories are stories that cannot be independently verified of the data that they purport to explain—that is, there is no observation that can disconfirm the adaptationist “hypothesis”, and the only data that “proves” the hypothesis is the data it purports to explain. EP hypotheses are not testable. Therefore EP hypotheses are just-so stories.

Sterelny and Griffiths (1999: 338) “… agree with the central idea of evolutionary psychology, namely, that we should look for the effects of natural selection on the psychological mechanisms that explain our behaviors, rather than on those behaviors themselves.” I disagree, since it is not possible that “psychological mechanisms” can be selected.

What is the relationship between environment and adaptation? First, we need to think of some “problems” that exist in the environment. One example is mate choice: Should one be faithful to their partner? When should one abandon their old partner? When should they help their kin find partners? When and how should one punish infidelity? This problem, pretty obviously, is evidence against the idea that adaptations are explained by the problem to which the adapted trait is the solution (see David Buller’s 2005 book Adapting Minds for strong critiques against “reverse engineering”). If—and only if—a single cognitive device exists that guides a creature’s behavior with respect to the issues of mate choice, the issue is then a single-domain, not multi-domain, problem, while there are different aspects of the same problem (see the questions above). The existence of said module explains why we think of mate choice as a single problem.

Sterelny and Griffiths (1999: 342) are hopeful in EP’s quest to discover our shared “human nature”, “But both the objective and subjective obstacles to carrying out this program remain serious.” The adaptationist programme, however, is unfalsifiable. “Particular adaptive stories can be tested, as we discuss below, but Gould and Lewontin argue that this does not test the idea of adaptationism itself. Whenever a particular adaptive story is discredited, the adaptationist makes up a new story, or just promises to look for one. The possibility that the trait is not an adaptation is never considered” (Sterelny and Griffiths, 1999: 237).

Adaptationist explanations (EP is—mostly—nothing but adaptationist explanation) are not scientific since they cannot be falsified—EP hypotheses are not falsifiable, nor do they generate testable predictions. They only explain the data it purports to explain—meaning that all EP adaptationist explanations are just-so stories. (Also see Kaplan, 2002 for arguments against the adaptationist paradigm.)


Even those who are sympathetic to the EP research programme, rightly, point out the glaring flaws in the programme. These flaws—in my opinion—cannot be overcome. EP will always be “plausible and speculatuve ” just-so stories that purport to explain the evolution of what, supposedly, are traits that were “selected for” in virtue of their contribution to fitness in the OEE. However, we do not (and cannot) know what the OEE was like—we would need a time machine. It is not possible for us to know the selective pressures that occurred on our ancestors in the OEE. We do know that increased reproductive efficiency in the current-day is not evidence that said trait was adaptive and selected in the OEE.

The mind is not modular; Tooby and Cosmides proposed a false dichotomy (their ICM vs SSSM) which is not valid (no one is a “blank slatist”, whatever that is); and the adaptationist paradigm is nothing but speculative just-so stories.

  1. For EP to be a valid research programme, EP hypotheses must generate testable, falsifiable predictions.
  2. EP cannot generate testable, falsifiable predictions (the hypotheses are inherently ad hoc).
  3. Therefore, EP is not a valid research programme.

There is no reason at all to accept any just-so story since these adaptive explanations cannot produce evidence that the trait was not a byproduct, due to genetic drift etc. Therefore EP is not a scientific enterprise; it only tells “plausible”, speculative stories just-so stories “… I view evolutionary psychology as more speculation than science. The conclusion I urge is, accordingly, skeptical. Speculation is just that: speculation. We should regard it as such. Evolutionary psychology as currently practiced is often speculation disguised as results. We should regard it as such” (Richardson, 2007: 25). This is the view that should be accepted in the mainstream, since there can be no evidence for the speculative stories of EP.