Evolutionary Psychology: A critique

In an extremely short span of time, evolutionary psychology has come to occupy the public imagination in a manner that perhaps only a few fields have. It’s not surprising that most of the psychology “hot takes” featuring in pop-culture magazines stem from poorly researched evolutionary psychology papers with extremely small sample size. As I was writing this article, the pop culture magazine “Insider” published an article explaining why we’re “hardwired” to become fascinated by true crime. The psychologist quoted in the article reasoned that our brains have an “innate” tendency to generate “fight or flight” response to “media reports” leading us to respond as if the adverse situations actually affect us[1]. This kind of reasoning, as we shall discuss later in this article, is typical in pop-evolutionary psychology.

However, my critique is not directed simply at popular manifestations of evolutionary psychology. I do think that many critics of evolutionary psychology often unfairly attack the entire field by citing specific instances. This approach is fatally flawed. It would be unfair to attack the field of evolutionary biology simply because many of its proponents were eugenicists in the early 20th century. Thus, while I will mention specifics, it’ll only be in the context of mainstream evolutionary psychology framework.

According to the philosopher of science Thomas Kuhn, the emergence of a scientific paradigm occurs when a group of scientists come to agree on foundational axioms that come to define the field itself. A paradigm is primarily, if not entirely, theoretical in nature. It provides “a map whose details are elucidated by mature scientific research”[2]. This map is essential as it helps scientists to navigate through the complexity of nature in a non-random manner. Here, I will be discussing the paradigm or the group of scientists who have come to virtually define the field of evolutionary psychology (EP). While there are multiple researchers whose work explores what EP aims to explore, they have either remained ambivalent or explicitly critical (ex- Jaak Paanksep) towards the foundational axioms of the field itself. These scientists are not included in EP paradigm.

Before we discuss the critique, it’s important to understand what the term actually entails based on the view of mainstream researchers on the field. In what follows, I will discuss the core tenets of evolutionary psychology through a purely descriptive lens.

What is Evolutionary Psychology?

The overwhelming majority of members in an ant nest tend to be sterile females incapable of reproduction. According to Darwin, natural selection favours those who are able to survive and continue the propagation of the species. Ants, on the other hand, are extremely altruistic and are willing to sacrifice for the greater good of the group. The existence of “neuter insects” like ants posited a “special difficulty” (as Darwin called it) to the theory of evolution[3]

In 1964, this problem was resolved by William D. Hamilton. A gene that causes an individual to behave in a self-sacrificing manner will lower its own chances of survival. However, if those self-sacrificing behaviours are directed towards saving close relatives, then the gene will be ensuring the survival of its own copies since the likelihood of your relatives carrying the same genes as you is extremely high. This, in short, is kin selection. A gene that reduces an individual’s direct reproductive success will evolve in an organism if the reproductive benefit (B) conferred by the gene to all of the individuals affected by it, multiplied by relatedness(r) {defined as the average relationship between the individual and the group sharing the genes} is greater than the cost(C) to the individual[4] [5]. Thus, Hamilton’s rule can be simplified quantitatively as:-

Br>C

Hamilton’s ideas were popularized most prominently through Richard Dawkins’ The Selfish Gene (1976). More relevant to our discussion, however, is the work of E. O. Wilson. Inspired by Hamilton’s work, Wilson did exhaustive research on insect societies. In his first major work, Wilson hinted at the impressive similarities between “insect and vertebrate societies.”[6]

Soon enough, Wilson formed a general theory which attempted to determine the biological basis for social behaviour in non-insect, including human, societies. This was called sociobiology, whose realm of investigation encompassed even complex manmade cultural systems like those of ethical systems and religion. In Wilson’s own words[7]:-

“If the brain evolved by natural selection, even the capacities to select particular aesthetic judgments and religious beliefs must have arisen by the same mechanistic process. They are either direct adaptations to past environments in which the ancestral human populations evolved or at most constructions thrown up secondarily by deeper, less visible activities that were once adaptive in this stricter, biological sense.”

This was the earliest iteration of what formed as a foundational axiom for evolutionary psychology. Though Sociobiology was a precursor to EP, EP’s claims are far more expansive than that of socio-biology.

Evolutionary psychology does not claim that there is a selection for “behaviour”. Natural selection only selects “for mechanisms that produce behavior.”[8] Thomson’s Gazelles exhibit a behaviour known stotting i.e. they jump into the air in plain sight of predators. This is a way in which they signal their fitness, basically telling the predator that the predator would be wasting their time chasing as they’re too fit to be caught[9]. Stotting only manifests in the presence of predators. It isn’t learned but inherited. In other words, if gazelles were raised in isolation without having encountered a predator, they’d still express stotting when they come across a new predator. What is inherited is not stotting per say but the proximate mechanism which makes stotting possible under the appropriate environmental trigger (the encounter with the pray).

Similarly, in human beings, behaviour evolved as a result of proximate mechanism of the brain under adaptive conditions. Is our brain designed to produce behaviour that maximize our fitness and reproductive success in the current environment? Evolutionary psychologists answer no. We’d all be standing in line eager to donate our eggs and sperms to cryobanks if this was the case. Our behaviour, far from being adaptive, is actually maladaptive in the current environment. We get around the natural consequences of our behaviour easily through the use of contraception, for instance. This does not mean the trait itself is a maladaptive trait. Traits are considered to be adaptive if they enhanced the chance of survival, fitness and reproduction of our ancestors. Human societies have changed radically in an incredibly short span of time on an evolutionary scale. Due to this time lag, it’s necessary to determine a specific point or environment in the past to which our current behaviours are adapted to. This environment is referred to as the Environment of Evolutionary Adaptadness (EEA). It is defined as “composite of environmental properties of the most recent segment of a species’ evolution that encompasses the period during which its modern collection of adaptations assumed their present form.”[10] This particular environment is usually associated with the Pleistocene (hunter-gatherer) period.

Evolutionary psychologists believe that “the mind is organized into modules or mental organs, each with a specialized design that makes it an expert in one arena of interaction with the world. The modules’ basic logic is specified by our genetic program. Their operation was shaped by natural selection to solve the problems of the hunting and gathering life led by our ancestors in most of our evolutionary history.”[11] This view is contrasted with domain general where the mind is seen as being equipped with general abilities required to resolve every problem. EPs and most cognitive psychologists now subscribe to the domain specific/massive modularity view.

Broadly speaking, evolutionary psychologists also believe in a common and universal human nature[12]. Since our evolution is “completed”, psychological modules form “a single, universal panhuman design, stemming from our long enduring existence as hunter-gatherers.”[13]

I’ll discuss and critique some of these axioms and many important specific claims in succeeding sections.

Modularity

The idea of massive modularity is perhaps one of the strongest hypothesis that EP has produced. The best way to comprehend this idea is to imagine the mind as being constitutive of multiple specialized computers which interact with each other to solve problems. These modules are restricted i.e. domain-specific and do not develop due to socialization. They are built-in mechanisms which come equipped with innate knowledge about their own speciality. Though they do interact with other “modules”, they operate primarily within their own “set of procedures, formats, and representational primitives closely tailored to the demands of its target problems.”[14]

This is helpful as instinctual actions do not require the rather tedious process of learning. In fact, Tooby and Cosmides refer to these computational systems as “learning instincts”[15]. This argument is at its best when describing the evolution of the “language instinct” combined with Noam Chomsky’s idea of universal grammar. I will not elaborate here on the same as it lies outside the purview of our discussion but would strongly urge the reader to read Pinker’s “The Language Instinct” and Dennett’s response to Chomsky in “From Bacteria to Bach and Back”.

It is not the idea of module that’s controversial. Some form of modularity is accepted by most mainstream philosophers and psychologists, including EP’s critics. The debate is usually about the nature and extent of the module. Jerry Fodor provides an interesting alternative explanation of how the functioning of the mind can encompass both domain-general and domain-specific mechanisms, which I discuss below[16].

Consider two modular processors- M1 is specialized to think only about triangles (P1) while M2 is specialized to think only about squares (P2). When M1 encounters a triangle, it is activated and scans the representation of triangle with the hardwired representation of triangle that it’s automatically equipped with. M1 is only activated when it encounters a triangle, not a square. The same applies to M2. Now, there has to be a procedure prior to the activation of these modules that identifies the representation in order to assign them to the appropriate models. This would entail a mechanism that recognizes representation as a whole. The absence of such mechanism would entail that there are distinct separate mechanisms which assign P1 to some modules (M1) and P2 to others. How did these separate mechanisms come to be then? They must’ve come through another set of distinct mechanisms and so on. This leads to an infinite regress. Now, the alternative explanation i.e. there is a domain general mechanism which assigns P1 to some modules and P2 to others severely undermines the case for domain specificity while holding a better explanatory value.

Does the claim of massive modularity stand up to experimental scrutiny? It does not. For starters, EPs claim that the mind is organized in the form of “mental organs” with specialized function whose basic logic is specified by “our genetic program”[17]. If this claim is right, one would expect a proportionate increase in genes and the modules of the human brain as the brain develops new feature. These growing genes would help in the formation of new modules. This is not the case. There is no correlation between brain complexity and frequency of genes. In fact, house mice has roughly as much genes as humans[18]. Despite the fact that our brain system is more complex, there is greater genetic specification for sensory receptors than there is for brain system.

How do our complex brain circuits develop in the absence of a genetic program for specification[19]? The cell production in utero develops in the ventricular and the subventricular zone (SVZ). The ventricular zone develops cells that make up the oldest evolutionary parts of the brain which help in controlling motor coordination, emotion (the limbic system) etc. while the subventrical zone is where the parts that help in higher cognitive abilities i.e. the neocortex develops. The cells in SVZ meander through other cells to reach their destination in order to form connections with other cells. This process is uniform across individuals and can be described as having a clear genetic structure. However, this is only true for the major structures. The specialized cognitive structures develop in the adult to meet environmental demands by subtracting cells through cell death and competition. An adult brain has fewer cells than that of an infant[20]. This subtraction mainly occurs through a process of spontaneous internal neural firings and as a response to sensory inputs. In the absence of these processes, the subtraction will not take place. For instance, keeping one eye closed while the visual system is developing will result in the malfunctioning of the cortex responsible for responding to visual inputs which will lead to the individual becoming functionally blind[21]. Thus, environmental stimuli is crucial for proper cortical development. Evolutionary psychologists don’t deny the environmental inputs. They see the environmental inputs as “triggers” for psychological adaptations/modules which are “developmentally timed to appear” in the same manner as “breasts and teeth”[22]. As we’ve seen, there is no “appearance” or “addition”. Insofar as there are any additive processes, they merely help in the development of raw materials for subtractive processes which work based on environmental inputs[23]. The Nobel-winning biologist Gerald Edelman describes this process as similar to that of natural selection as overproduction of neurons is followed by the retention of only those neurons that are most responsive to environment[24].

That cortical development is affected significantly by environmental factors undermines evolutionary psychology’s thesis that our brain is comprised of modules that developed according to the demands of the environment of evolutionary adaptadness. Our brain regions have the ability to perform functions of other regions and reorganize as and when the environment demands. This is referred to as neural plasticity. To illustrate how this works: — the removal of semicircular canals, which help in balancing, results in the regaining of our sense of balance in a very short period. This does not happen because of formation of new neural connections. Rather, it seems likely that other systems, like the visual pursuit system serve as substitutes and help in vestibular processing. We now also have reasonably strong evidence about cross-modal connections between sight and smell[25]. Why do these findings undermine massive modularity?

Information overlap and the ability of brain regions to substitute for other regions casts serious questions on domain specificity. Instead, as Buller and Hardcastle(2005) argue, it is more likely that our brain regions are domain dominant i.e. they perform specific functions but are able to substitute as and when the environmental and developmental changes demand.

To be fair, evolutionary psychologists have conducted experiments in an attempt to verify the existence of specific modules. The clinical psychologist Simon Baron-Cohen, for instance, has conducted false belief studies which apparently serve as evidence for the theory of mind module. Simply put, theory of mind is the ability of individuals to understand what others think/believe/feel and distinguish it from their own. In a false belief test, the subject watches individual A and B in a room. Individual B keeps a ball under a box and leaves the room. While B is away, A removes the ball from under a box and places it under a can. The subject is then asked where B will search for the ball when he returns. Most children with autism answer that B will search in the can, indicating the lack of awareness about false beliefs. Baron-Cohen posits that this is due to the fact that those with autism lack the theory of mind module[26]. The problem with this is that autism is not simply the inability to understand others. It involves a plethora of other symptoms i.e. preferring routine and predictability, fearing environmental change etc. Moreover, as Paul Bloom points out, there is no good reason to believe that the false belief study actually tests the existence of TOM. In fact, children younger than 3 year olds show plenty of signs of having TOM[27].

Surveying the current empirical evidence, the cognitive psychologist Cecilia Heyes argues that a better explanatory model in line with empirical evidence is one that sees the mind as being comprised of cognitive gadgets. Though we’re born with some “starter kits”, it is only through an interaction with our environment and culture that we acquire mindreading, imitation, language etc. This model predicts rapid evolution and thus is very optimistic about our ability to adapt to technological changes[28].

Sex differences

The topic of sex difference is contentious sociologically, culturally as well as scientifically. It is often the case that evolutionary psychology is unfairly criticized for assertions that it never makes in the first place. Consider John Gray’s bestseller “Men are from Mars, Women are from Venus”. This is a view that no credible evolutionary psychologist shares. Many, like Simon Baron-Cohen, explicitly denounce it as “too extreme” and unscientific to be taken seriously[29]. For this reason alone, I will completely ignore these self-help bestsellers and focus only on the claims of mainstream evolutionary psychologists. My argument is twofold- (i) the claims of evolutionary psychologists on sex differences is based on shaky scientific grounds and (ii) contrary to the protestations, these claims are often explicitly or implicitly normative.

The idea of sex difference in EP is inextricably tied to EEA. Our Pleistocene ancestors, EP claims, were hunter and gatherers. There was a natural division of labour as males were more likely to hunt while females took care of the young. It is hard to read the works of evolutionary psychologists and not come out convinced that they’re claiming every aspect of our mating behaviour and psychology can be explained in evolutionary terms, occasional caveats notwithstanding.

The worst manifestation of this is the theory of rape as an evolutionary adaptation. Though this hypothesis was fully developed by Randy Thornhill and Craig Palmer, it has found support among other mainstream proponents as well. Robert Wright notes that, in Darwinian terms, “A female is better off mating with a good rapist”[30]. Female resistance too is favoured by natural selection as it does the job of “filtering” the strong rapists from the weak ones. This does not meant “she wants it”. It is what natural selection “wants”. Thus, even when females don’t consciously prefer a “certain kind of male”, they unconsciously do in practical terms[31]. David Buss, one of the founders of EP, supports this view emphasizing on the reproductive advantages of rape[32]. Pinker has described Thornhill and Palmer’s book as “courageous, intelligent and eye opening book with a noble goal” which is armed with “logic and copious data”[33]. That’s quite high praise. So, what exactly are Thornhill and Palmer’s claim and how does their data hold up? You’ll be surprised.

Since females invest more in their offspring i.e. nine months of metabolic trauma and years of caring, they’re likely to be choosy in choosing a mate. Males, on the other hand, can have a large amount of offspring with very little investment. This asymmetry results in different mating strategies and consequently physical differences as it relates to aggression. Thornhill and Palmer propose two alternatives to prove the biological origins of rape- by-product and adaptation[34]. The idea of rape being a by-product is a non-starter given that every human attribute can be described as an evolutionary by-product, directly or indirectly. It is also unscientific given Thornhill and Palmer’s admission that “whether evolution applies or not is never a question” (unfalsifiable)[35]. What is controversial here is that Thornhill and Palmer argue that rape is a direct adaptation.

The authors argue that rape is primarily a sexual act, not an act of power or aggression. For those unable to find mates, rape becomes the last resort to ensure the propagation of genes. Thus, a rape causing gene would increase rather than a rape avoiding gene among disenfranchised men[36]. In this theory, all men are born as “potential rapists” but the eventual act of rape depends upon its net reproductive benefit (calculated unconsciously, of course). Women’s psychological pain is also direct adaptation since it forces them to focus on the losses, takes away their ability to choose mates and ensures they avoid the repetition of such an event[37].

In what can only be described as grotesque in hindsight, Thornhill and Palmer claim that their critics have been programmed to reject their evolutionary explanation because “Evolved psychological intuitions about behavioral causation can mislead individuals into believing that they know as much as experts do about proximate human motivation”. [38] This would be considered the logical fallacy of appealing to authority in any other context or for that matter, scientific field. It is simply dressed in EP jargon here to make it “sound” scientific.

Thornhill and Palmer make a series of prediction, which they claim is verified by their research that supports the direct-selection theory. Prediction and empirical facts serve as a backdrop of any good scientific theory. The authors’ evidence can only be described as weak at best and dishonest at worst. In order to prove that reproduction is a rapist’s primary goal, the authors claim that most rape victims are in their prime reproductive years. The data that they cite doesn’t support this. 29% of US rape victims are under 11 while 15% of the female population is under-11. In other words, under-11s are over represented by a substantial factor. Thornhill and Palmer acknowledge this but in a classic case of special pleading, they claim that the data doesn’t indicate “proportion of the victims under 11 who were exhibiting secondary sexual traits”. [39]

If psychological trauma functions as an adaptation, as the authors claim, then we’re likely to find women of reproductive age experience more psychological pain than others. The data that the authors cite contradicts their claim as women of reproductive age face as much trauma and violence as older women. In order to get around this, the authors lump older women and under-11s together to argue that the evidence supports their claim. The original authors of the studies that Thornhill and Palmer cite were understandably indignant at the gross misrepresentation of the data. The psychologist Anthony Goldsmith, for instance, criticized Thornhill&Palmer’s work as “bad analysis of data and bad science. It’s not nice when our data is misused”[40].

The authors are not merely making a descriptive claim. Contrary to their protestations, they are doing advocacy, not science. They are not formulating a theory that fits the data. They’re distorting the data to ensure it fits their theory. This is evident through their disdain for “academic feminists and sociologists” suffering from “biophobia” whose policy “proposals uninformed by evolutionary theory increases the incidence of rape”[41].

Thornhill and Palmer make the political and prescriptive nature of their theory explicit. “Evolutionary informed” ways to prevent rape include creating social and physical barriers such as locating summer camps for boys and girls at two opposing ends and using a supervisor/chaperone in early relationships[42]. “Evolutionary informed” counselling includes teaching women that post-rape trauma is a psychological adaptation and to use psychotropic medications “cautiously and selectively” (not because of their side effects but in order “not to eliminate the defense that psychological pain provides”). Women should also be informed “about cues that may increase the probability of rape”. What are these cues? Wearing “sexy clothing”. Thornhill and Palmer write[43]:-

“Young women should also be informed that female choice, over the course of the evolution of human sexuality, has produced men who will be quickly aroused by signals of a female’s willingness to grant sexual access. And it should be made clear that, although sexy clothing and promises of sexual access may be means of attracting desired males, they may also attract undesired ones.”

Their conservative social advocacy combined with the deliberate distortion of data dispels all illusions about their claim of being just disinterested scientists.

Perhaps I’m not being fair to the field by citing one specific instance. It is indeed unfair to reduce EPs ideas on sex differences to Thornhill and Palmer’s theory. I have no intention of doing that as I will look into other claims. It is important to note here, however, that Thornhill and Palmer’s ideas are not fringe[44] in EP. As we have seen, they have been praised by leading experts in EP.

EP has a rather simplistic narrative on mating. In this narrative, men have evolved to mate with young beautiful women while women have evolved to look for high status men. In what Helen Fisher calls the “sex contract”, men offer resources to women in exchange for sex[45]. The evolutionary end goal for men and women are different. Men want to leave behind as many genetic offspring as they can while women want to choose limited but high quality mates. Pinker calls this “the genetic economics of sex”[46]. As Wilson and Daly write “Men lay claim to particular women as songbirds lay claim to territories, as lions lay claim to a kill, or as people of both sexes lay claim to valuables. Having located an individually recognizable and potentially defensible resource packet, the proprietary creature proceeds to advertise and exercise the intention of defending it from rivals.”[47] Robert Wright is even more explicit as he writes “men (consciously or unconsciously) want as many sex-providing and child-making machines as they can comfortably afford, and women (consciously or unconsciously) want to maximize the resources available to their children”. In other words, the relationship between men and women is one of “mutual exploitation”[48]. One hardly needs to explain how this theory is perfectly commensurate with the archetype of the gold-digger woman and the sex-hungry man. While my critique is not intended to be primarily political or rhetorical, it is important to point out that contrary to what many claim, EP proponents agree that their ideas have clear social ramifications.

A close rhetorical reading makes it clear. For Robert Wright, serial monogamy is the worst of both worlds. The relationship between men and women can be best understood, according to Wright, as an evolutionary arms race. Natural selection favours males who are good at deceiving females and favours females who are good at detecting deception[49]. In light of the conflicting interest between two sexes, only a polygamous society would result in a market that would “right itself”. Dowry, Wright claims, is the result of the disequilibrium that monogamy brings with it[50]

Women are not as resistant to sharing a man as men as they’d prefer living with an unfaithful rich man than a “ne’er-do-well” in poverty, “typically”[51]. However, a polygamous society has serious problems as it allows a few powerful women to grab all the women “from the jaws”[52]. This leads to inegalitarian distribution of “female resources” and increases the risk of violence among men. Having a woman in a man’s life has a “pacifying effect”.

How would a society consistent with evolutionary psychology look like? Victorian England, answers Wright. Good financial prospects for the wife and a pleasant visual and auditory environment (good looks) for the husband[53]. Men were allowed to go to brothels but it didn’t lead to desertion of marriage because “women, more easily than men, can reconcile themselves to living with a mate who has cheated”[54] . Wright assures us that he’s not making a prescriptive argument. This does not seem to be the case given that he gives considerable attention to criticizing feminists and blaming them for contemporary problems. The impulses of evolutionary psychology are strong and innate. Ignoring them leads to a society with “fatherless children; lots of embittered women; lots of complaints about date rape and sexual harassment; and the frequent sight of lonely men renting X-rated videotapes while lonely women abound. It seems harder these days to declare the Victorian war against male lust ‘pitiable’”[55].

To recap, Victorian society consistent with EP gave respect to women[56], kept marriage stable and its sexual repression and strict divorce laws were “strikingly well-tailored”[57]. Contemporary feminist movements advocating for sexual freedom and innate symmetry of sex, on the other hand, have produced a society strife with male alienation, fatherless children and embittered women. The social ramifications of standard EP narrative couldn’t be more explicit. Wright admits that he’s offering “Darwinian Self Help” by shedding light on the “practical applications of Evolutionary Psychology”. These practical applications are, of course, socially conservative. A “proliferation of low cut dresses” will lead to a decrease in “men’s commitment” as well as respect for women[58]. If you do this, men will reduce you to a “subhuman status” worthy of contempt[59]. In Wright’s words, “if you want to hear vows of eternal devotion right up to your wedding day — and if you want to make sure there is a wedding day — don’t sleep with your man until the honeymoon.” This principle is “rooted firmly in the male mind”.

The empirical research in sex differences as it pertains to evolutionary psychology doesn’t seem to support its axioms as robustly as its proponents like to claim. David Buss has conducted the most comprehensive survey on this comprised of 4.601 men and 5,446 men across 6 continents[60]. Buss found that males, on average, preferred those who were 2.66 years younger than them. Females, on the other hand, preferred at 25.4 years to marry a man of 28.8 years. This seems to confirm the EP hypothesis at first glance. A closer look, however, shows otherwise. The average age of Buss’s male respondents is 23.49 years, which is to say that it only proves that young men prefer young women. A look at actual marriages show that on average males marry females who are around 2.9 years younger than them. If men actually preferred to marry woman who are at the peak of their reproductive fertility, as Buss claims, then one would expect thirty year olds to marry twenty year olds. Why do we find such a small age discrepancy? Could it simply be the case that the preference for marriage has more to do with age similarity than age differences?

A hypothesis proposing such a model would nevertheless have to explain the small age gap that does exist. Buller proposes an alternative hypothesis of age homogamy. Since males achieve reproductive maturity later than females and since the competition among men is higher, one would expect such an age difference to exist[61]. This hypothesis of adjusted age homogamy makes the same prediction as Buss’. In order for evolutionary explanation to be the most plausible, it has to make all other plausible hypotheses redundant, which is clearly not the case here.

Evolutionary psychologists have also claimed to have found the perfect waist-to-hip ratio of female body that humans evolved to admire (0.70). This “adaptation” indicates peak reproductive potential and is therefore perceived to be a measure of female attractiveness. Though this has been replicated across many cultures, claims of it being universal are yet to be conclusively determined. In Peru’s isolated indigenous population, for instance, males rated females with 0.90 waist-to-hip ratio as “most attractive” (in American culture, this would be considered as “overweight”). Those with 0.70 waist-to-hip ratio were described as sick (“had diarrhea a few days ago”)[62]. Similar preferences were found among the hunter gatherer Hadja tribes[63]. These studies are crucial because the populations are isolated from cultural influences and are hunter-gatherers, similar to what our ancestors in EEA may have been.

Buss’ research has shown that, compared to culture, “the effects of sex on mate preferences were small”[64]. Only 2.4% of the variance is due to sex. In Buss’ own words “there may be more similarity between men and women from the same culture than between men and men or women and women from different cultures”. Among thirteen variables, the first four preferences for males and females are the same i.e. kind and understanding, intelligent, exciting personality and healthy. Physical attractiveness is rated at 5 by men and at 7 by women. This difference is statistically significant. In Buss’ study, women actually put “physical attractiveness” (7) above “good earning capacity” (9). The difference might not be as statistically significant in this case but one would expect there to be a clear and wide difference if evolutionary psychology’s axioms were to be held true.

We encounter the same inconclusive data when it comes to a clear demarcation between “male” and “female” brain. That there are differences is not a matter of debate. What those differences mean, on the other hand, is a matter of serious debate (see Pinker 2008[65], Baron-Cohen 2003[66],Hooven 2021[67] for critique- see Jordan-Young 2010[68] , Rippon 2019[69], Fine 2010[70], Fuentes 2012[71]. For a methodological critique of neuroscientific approach see Satel and Lilienfield 2013[72]). Given its adherence to these unresolved debates as axioms, one wonders how reliable, indeed scientific, can evolutionary psychology claim to be.

The Future of Evolutionary Psychology

There multiple areas where evolutionary psychology has proven to be quite successful. Examples include our innate fear of snakes and spiders[73][74][75], incest avoidance[76] etc. These are on reasonably strong grounds because phylogenetic comparative analyses is possible i.e. these behaviours are common to mammals.

There are primarily (but not exclusively) three ways in which adaptationist hypotheses are tested i.e. phylogenetic analyses, phenotypic manipulation/laboratory studies and transplant studies. Experimental manipulations include, for example, artificially shortening and lengthening tail of birds and manipulating genes to affect phenotypic features. Needless to say, the crucial techniques used to test adaptationist hypotheses in animals cannot be tested in humans, for obvious and reasonable ethical constraints.

In evolutionary biology, a combination of multiple techniques (such as ones described above) are used to confirm/refute adaptationist hypotheses. A particularly interesting example of this is the “sword” of sword-tailed fishes. Though Darwin hypothesized these “swords” to be adaptations due to sexual selection, it took over a hundred years to confirm this[77]. Scientist first had to prove that females are indeed attracted to the colored sword, not some other covarying traits. This was done by cutting off swords and attaching a colored swords in some and clear plastic in others. The females preferred colored swords, proving that it was the sword itself that the female preferred. This did not mean that the sword evolved due to preference of female. For this to hold true, the preference for swords has to exist before the emergence of sword. This was done by adding swords to closely related species of the genus Xiphophorus who naturally don’t possess such tail. It was found that even in those species, the females preferred those with tails[78]. Thus, the idea that swords are an adaptation which emerged as a result of sexual selection is fairly well supported by the empirical evidence.

In principle, adaptationist hypotheses concerning human behaviour can be tested empirically. We have observed some rare examples of human evolutionary adaptations in real time, particularly HbS allele as it relates to malaria resistance[79]. When it comes to behavioural traits, on the other hand, things become messy. For starters, almost all of the species in the tribe Hominini are extinct. The only ones that exist today are chimpanzee and bonobos (and humans, of course). In the genus Homo, no other species except humans survive. The Xiphophorus genus, in contrast, has 28 extant species. Yet, evolutionary psychologists claim that they draw conclusions through comparative phylogenetic data (which is rarely the case, understandably so given the grand claims that EP makes).

A striking example of this is Geoffrey Miller’s assertion that artistic/creative/cognitive ability in males evolved due to sexual selection. This, Miller claims, explains why “males produce an order of magnitude more art than females”[80] . For this to be true, artistic males had to have higher fitness than non-artistic males. Further, females with preference for artistic males have had to have higher fitness than those who don’t. Most importantly, preference for artistic ability must predate artistic ability itself (as we noticed in the swordfish example). This does not seem to be the case as non-human primates engage display immense interest in artistic ability when provided with paints, sans any rewards[81]. This leaves no place for Miller’s argument that sexual selection leads to the development of artistic ability. Conscientious readers might be tempted to question Miller’s claim as to whether males actually produce more and better artistic works. I have ignored that question because his basic premise falls down in the face of phylogenetic evidence[82].

The idea that some of our behaviour is innate and adapted to a past environment, i.e. Pleistocene, is plausible but untestable. We don’t know for certain and will likely never know the behaviour that was prevalent in EEA. All we can do is make plausible guesses, each of which might turn out to be just as likely as the other ones.

Evolutionary psychology is not a non-starter like homeopathy or astrology. It is not “pseudoscience”. It is, to use Pigliucci’s term, a “quasi-science”[83]. As it currently stands, almost none of its axioms (EEA, modularity etc.) are as robust as, say, the big bang for physics or the theory of evolution for biology. There are many hypothesis which stand on good scientific grounds, none of which conclusively confirm the paradigm. Evolutionary psychology aims to be psychology’s grand theory of everything. However, most grand theories of everything have fallen down- Freud, Jung, Skinner etc. All of them were widely popular and considered to be objective science in their time. In particular, behaviourism shared the same convictions about itself as EP now does. Given its grand claims and ambitions, not to mention the tendency of its proponents to label their critics as “blank slaters” and “creationists of the mind”, it is highly unlikely that the fate of evolutionary psychology will be any different.

For evolutionary psychology to become more scientifically robust, it needs to abandon its paradigm along with its adherence to adaptationism. Most traits are neutral. Nose, for instance, comes in many types. Whether one has a long or a short nose has no impact on one’s fitness or survival. There is no reason why our “Pleistocene” behaviours will be any different.

A scientifically robust evolutionary psychology will be a lot less interesting, less grander, less speculative and of course, less popular. Nevertheless, it will still have the potential to shed light on remnants from our evolutionary past.

Notes

[1] https://www.insider.com/gabby-petito-brian-laundrie-missing-found-true-crime-tiktok-2021-9#:~:text=22%2Dyear%2Dold%20Gabby%20Petito,so%20rapidly%20on%20social%20media.

[2] Kuhn, Thomas S, The Structure of Scientific Revolutions. Chicago, IL: University of Chicago Press, 1996.

[3] Darwin, Charles, 1809–1882. On the Origin of Species by Means of Natural Selection, or Preservation of Favoured Races in the Struggle for Life. London :John Murray, 1859.

[4] Hamilton, William D. (1964). “The genetical evolution of social behaviour. I.” J. Theoretical Biology 7: 1– 16.

[5] Hamilton, William D.(1964). “The genetical evolution of social behaviour. II.” J. Theoretical Biology 7: 17–52.

[6] Wilson, E O. The insect societies. Belknap Press. 1971.

[7] Wilson, Edward O. (1978). On Human Nature. Cambridge, MA: Harvard University Press.

[8] Cosmides, Leda, and John Tooby (1987). From Evolution to Behavior: Evolutionary Psychology as the Missing Link. In J. Dupré (ed.), The Latest on the Best: Essays on Evolution and Optimality (pp. 277–306). Cambridge, MA: MIT Press

[9] C. D. FitzGibbon, and J. H. Fanshawe. “Stotting in Thomson’s Gazelles: An Honest Signal of Condition.” Behavioral Ecology and Sociobiology 23, no. 2 (1988): 69–74. http://www.jstor.org/stable/4600191. Whether this is actually honest signalling or Zahavian handicap principle hasn’t been conclusively resolved yet and lies outside the scope of this article

[10] Tooby, John, and Leda Cosmides (1990). The Past Explains the Present: Emotional Adaptations and the Structure of Ancestral Environments. Ethology and Sociobiology 11: 375–424.

[11] Pinker, Steven (1997). How the Mind Works. New York: Norton.

[12] Symons, Donald (1995). Beauty Is in the Adaptations of the Beholder: The Evolutionary Psychology of Human Female Sexual Attractiveness. In P. R. Abramson and S. D. Pinkerton (eds.), Sexual Nature, Sexual Culture (pp. 80–118). Chicago: University of Chicago Press.

[13] Cosmides, Leda, John Tooby, and Jerome H. Barkow (1992). Introduction: Evolutionary Psychology and Conceptual Integration. In J. H. Barkow, L. Cosmides, and J. Tooby (eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture (pp. 3–15). New York: Oxford University Press.

[14] Cosmides, Leda, and John Tooby (1994). Origins of Domain Specificity: The Evolution of Functional Organization. In L. A. Hirschfeld and S. A. Gelman (eds.), Mapping the Mind: Domain Specificity in Cognition and Culture (pp. 85–116). New York: Cambridge University Press

[15] Cosmides, Leda, and John Tooby (1997). The Modular Nature of Human Intelligence. In A. B. Scheibel and J. W. Schopf (eds.), The Origin and Evolution of Intelligence (pp. 71–101). Sudbury, MA: Jones and Bartlett.

[16] Fodor, Jerry (2000). The Mind Doesn’t Work That Way: The Scope and Limits of Computational Psychology. Cambridge, MA: MIT Press

[17] Pinker, p. 21

[18] Buller, D. J. (2005). Adapting minds: Evolutionary psychology and the persistent quest for human nature. Cambridge, Mass: MIT Press.

[19] For an interesting and well-argued hypothesis on how our brain came to acquire a brain so vastly different from other primates, check out R. L. Buckner and F. M. Krienen, “The evolution of distributed association networks in the human

brain,” Trends in Cognitive Sciences 17 (2013): 648–665.

[20] Ackerman S. Discovering the Brain. Washington (DC): National Academies Press (US); 1992. 6, The Development and Shaping of the Brain. Available from: https://www.ncbi.nlm.nih.gov/books/NBK234146/ .Note- The book as a whole has some dated unscientific aspects, especially sections on homosexuality and AIDS. However, the particular section referred to describes standard mainstream science in a good introductory manner.

[21] Buller, p. 133

[22] Cosmides, Leda, and John Tooby (1992). Cognitive Adaptations for Social Exchange.

In J. H. Barkow, L. Cosmides, and J. Tooby (eds.), The Adapted Mind: Evolutionary Psychology

and the Generation of Culture (pp. 163–228). New York: Oxford University

Press.

[23] Elman, Jeffrey L., Elizabeth A. Bates, Mark H. Johnson, Annette Karmiloff-Smith,

Domenico Parisi, and Kim Plunkett (1996). Rethinking Innateness: A Connectionist Perspective

on Development. Cambridge, MA: MIT Press.

[24] Edelman, Gerald M. (1992). Bright Air, Brilliant Fire: On the Matter of the Mind. New

York: Basic Books.

[25] Kaeppler, K. Crossmodal Associations Between Olfaction and Vision: Color and Shape Visualizations of Odors. Chem. Percept. 11, 95–111 (2018). https://doi.org/10.1007/s12078-018-9245-y

[26] Baron-Cohen, Simon (1995). Mindblindness: An Essay on Autism and Theory of Mind.

Cambridge, MA: MIT Press.

[27] Bloom, Paul, and Tim P. German (2000). Two Reasons to Abandon the False Belief

Task as a Test of Theory of Mind. Cognition 77: B25–B31.

[28] Heyes, C. (2018). Cognitive gadgets: The cultural evolution of thinking. Harvard University Press. I have avoided elaborating here intentionally. Interested readers are highly recommend to read the book which argues for an alternative “cultural evolutionary psychology” from an empirical perspective.

[29] Baron-Cohen, S. (2003). The essential difference: The truth about the male and female brain. New York: Basic Books.

[30] Wright, Robert. 1994. The moral animal: evolutionary psychology and everyday life. New York: Pantheon Books.

[31] Wright, p. 52–53

[32] Buss, David M. 2003. The evolution of desire: strategies of human mating. New York: Basic Books. 270–5

[33] https://mitpress.mit.edu/books/natural-history-rape

[34] Thornhill, R. and C. T. Palmer (2000). A Natural History of Rape: Biological Bases of Sexual Coercion. Cambridge, Mass.: MIT Press

[35] Thornhill and Palmer, p. 12

[36] Coyne, J. A. (2003). Of vice and men: A case study in evolutionary psychology. In C. B. Travis (Ed.), Evolution, gender, and rape (pp. 171–189). MIT Press.

[37] Thornhill and Palmer, p. 85

[38] Thornhill and Palmer, p. 114…

[39] Thornhill and Palmer, p. 72

[40] Coyne, p. 189

[41] Thornhill, R. and C. T. Palmer. (2000). Why men rape. The Sciences Jan./Feb.: 30–36.

[42] Thornhill and Palmer, p. 185

[43] Thornhill and Palmer, p. 181

[44] There are certain theories which are indeed fringe in EP and criticized by most mainstream evolutionary psychologists. The most prominent example of this is the white supremacist anti-semitic evolutionary psychologist Kevin MacDonald’s theory of Jews being evolved to be ethnocentric, tribalistic and anti-white(MacDonald, Kevin B. 1998. The culture of critique: an evolutionary analysis of Jewish involvement in twentieth-century intellectual and political movements. Westport, Conn: Praeger). Another is LSE’s evolutionary psychologist Satoshi Kanazawa’s claim that black women are less physically attractive than women of other races(“Kanazawa Statement | Academia | Science”. Scribd.com. 29 March 2016)

[45] Fisher, Helen E. 1982. The sex contract: the evolution of human behavior. New York: W. Morrow

[46] Pinker, Steven. 2002. The blank slate: the modern denial of human nature. New York: Viking.

[47] Barkow et al. (1992), p. 289.

[48] Wright, p. 96

[49] Wright, p. 61

[50] Wright, p. 96

[51] Wright, p. 95

[52] Wright, p. 100–101

[53] Wright, p. 109

[54] Wright, p. 142–144

[55] Wright, p. 145

[56] Wright, p. 135

[57] Wright, p. 142–143

[58] Wright, p. 141

[59] Wright, p. 73–74

[60] Buss, David M. (1989). Sex Differences in Human Mate Preferences: Evolutionary

Hypotheses Tested in 37 Cultures. Behavioral and Brain Sciences 12: 1–49.

[61] Buller, p. 214

[62] Yu, Douglas & Shepard, Glenn. (1998). Is Beauty in the Eye of the Beholder?. Nature. 396. 321–322. 10.1038/24512.

[63] Dixson, Barnaby J.; Dixson, Alan F.; Morgan, B; Anderson, M. J. (June 2007). “Human physique and sexual attractiveness: Sexual preferences of men and women in Bakossiland, Cameroon”. Archives of Sexual Behavior. 36 (3): 369–375

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· [65] Pinker, Susan. 2008. The sexual paradox: men, women and the real gender gap. New York: Scribner.

[66] Baron-Cohen, Simon. The Essential Difference: The Truth About the Male and Female Brain. New York, NY: Basic Books, 2003.

[67] Hooven, Carole. T: The Story of Testosterone, the Hormone that Dominates and Divides Us. United States: Henry Holt and Company, 2021.

[68] Jordan-Young, R. M. (2010). Brain storm: The flaws in the science of sex differences. Harvard University Press.

[69] Rippon, Gina (2019). Gendered Brain: the new neuroscience that shatters the myth of the female brain. London: The Bodley Head Ltd

[70] Fine, Cordelia. Delusions of Gender : the Real Science behind Sex Differences. London :Icon, 2010

[71] Fuentes, Agustin. 2012. Race, monogamy, and other lies they told you: busting myths about human nature. Berkeley: University of California Press

[72] Satel, S., & Lilienfeld, S. O. (2013). Brainwashed: The seductive appeal of mindless neuroscience. Basic Books.

[73] Hoehl S, Hellmer K, Johansson M, Gredebäck G. Itsy Bitsy Spider…: Infants React with Increased Arousal to Spiders and Snakes. Front Psychol. 2017 Oct 18;8:1710. doi: 10.3389/fpsyg.2017.01710. PMID: 29093687; PMCID: PMC5651927.

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[77] Darwin, Charles, and John Murray. 1871. The descent of man: and selection in relation to sex. London: John Murray, Albermarle Street.

[78] Kaplan, Jonathan., Pigliucci, Massimo. Making Sense of Evolution: The Conceptual Foundations of Evolutionary Biology. Germany: University of Chicago Press, 2010.

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[82] Pigliucci, p. 164–165

[83] Pigliucci, Massimo. 2010. Nonsense on stilts: how to tell science from bunk. Chicago: University of Chicago Press.