An argument which is potentially more troubling is one presented by Ed Clint here which suggests that Watson's talk was an attack on the entire field of evolutionary psychology, and is thus an example of science denialism. This characterisation of her position seems unfair to me given that it seemed that she was attacking the bad science, not the entire field, but I thought it might be a good idea to discuss why the field of evolutionary psychology is often dismissed and what distinguishes the good science from the bad.
The latest deadweight dragging us (evolutionary biology) closer to phrenology is evolutionary psychology, or the science formerly known as sociobiology. If evolutionary biology is a soft science, then evolutionary psychology is its flabby underbelly. - Jerry Coyne1.
Given the somewhat controversial title of this essay, it is
perhaps necessary for me to preface it with a few disclaimers. Firstly, I am
not a creationist and, for all intents and purposes, evolution is TrueTM.
Secondly, whenever somebody voices their skepticism over the veracity of
evolutionary psychology, they are often met with the retort, “Do you not
believe that the brain is a product of evolution?” with the implication that
since behaviors are the product of the brain, and the brain is a product of
evolution, then behaviors are the product of evolution. This logic, however, is
flawed for reasons I will discuss later but I do accept that the brain is an
evolved organ with implications for resulting behaviors. And thirdly, this is
not a broad scale attack on evolutionary psychology – instead, my focus is on
the particular approach to evolutionary psychology known as the “Santa Barbara
church of psychology”2.
To distinguish between the two approaches, I will follow the
nomenclature used by Gray, Heaney and Fairhall3 where they refer to this
approach as Evolutionary Psychology (EP). This approach (used by popular
authors like Steven Pinker in his “How the Mind Works”) attempts to explain a
wide range of human behaviors, like whether we have an evolutionary preference
for green lawns, with an emphasis on the concept of a modular mind, and
utilises a cartoonish view of the Pleistocene – with all considered, we have to
wonder whether it should be rebranded as the “Hanna-Barbera church of
psychology”.
THE SELECTION OF ADAPTIVE EXPLANATIONS
The standard tool in this area is the explanatory strategy
called “reverse engineering”4. While ‘normal’ engineering
attempts to design solutions to problems, Evolutionary Psychologists argue that
current features of the human mind can be explained as solutions to problems
presented in our Environment of Evolutionary Adaptedness5. For this to be a valid explanatory strategy, Gray et al. argue
that three criteria must be met:
- all traits are adaptations
- the traits to be given an adaptive explanation can be easily characterized
- plausible adaptive explanations are difficult to come by.
As we would expect, these assumptions are frequently
violated. Given what we now know about evolutionary processes, the first is
perhaps the easiest to refute as it is obvious that not all traits come about
as a result of natural selection. Ignoring the more complicated issues of genetic
drift, pleiotropy, and epistasis, a perfect example of why we should be
skeptical of this claim is Gould and Lewontin’s6 concept of the spandrel
which, in simple terms, is a byproduct of the selection of another trait. In
this sense, asking for the adaptive explanation for some behaviors is akin to
asking what the selection pressure was that caused blood to be red.
Gray et al. discuss the latter two issues in more
detail but essentially the second claim is problematic given the lack of
discrete boundaries for certain traits and they use Lewontin’s7 example
of the “chin” to demonstrate this. They also extensively dissect the third
criterion but a successful rebuttal of this is perhaps exemplified by Rosen’s8 suggestion that the only two constraints on adaptive explanations are
the inventiveness of the author and the gullibility of the audience. It is
important to note that I am not suggesting that we should abandon attempts to
describe behaviors using adaptive explanations, nor am I saying that all
behaviors are spandrels or the result of obscure evolutionary processes, but
rather I am highlighting the fact that a plausible story is not evidence in
itself. This position is described by Williams9 thusly:
The ground rule - or perhaps doctrine would be a better term - is that adaptation is a special and onerous concept that should be used only where it is really necessary.
As is clear to most evolutionary biologists, and other
interested skeptical parties who are less than enamoured by the efforts of
Evolutionary Psychologists, the approach described by Williams above is rarely
followed and instead these scientists appear to fire off adaptive explanations
with reckless abandon, with their work often consisting of nothing more than
folk wisdom and a post hoc just-so story explanation. To attempt to circumvent
this, Gray et al. propose two “common sense” tests: The Grandparent
Test, and the Lesser-Spotted Brown Gerbil Test. The first asks us to consider,
“Does this work give us any insight into human behavior and cognition beyond
popular knowledge?” and the latter asks, “Would this research be publishable in
major international journals if the species was a small noncharismatic mammal
rather than our own?”. Although these ‘tests’ are only guides and should not be
used as definitive tools for ruling out instances of research, it is
interesting to note that most examples of EP found in journals fail these basic
tests. However, picking examples of this kind to discuss here would be like
shooting fish in a barrel, so instead I will look at research behind the
evolutionary explanations for cheater detection.
CHEATER DETECTION
Cosmides10 proposed the “social exchange algorithm”
which argues that for cooperation to be maintained in a society, we must be
able to detect cheaters – with this consistent selection pressure present,
humans must have evolved a cognitive mechanism to do this. This idea began with
the research using the Wason Card Selection Task which utilises a generalised
if P, then Q rule.
The task is straightforward: Given the cards presented in
the image above, which cards should you turn over to test the claim that 'if a
card shows an even number on one face, then its reverse side will be red'? The
correct solution is that you should turn over the
Despite the apparent simplicity of this task, Wason11 found that only 10% of his subjects answered this correctly. However, the
interesting twist on this logical conundrum is that when the context of the
problem is framed in a way that is socially relevant, people tend to perform
far better. That is, accuracy increases if we change the proposition to: “if
you are drinking alcohol then you must be over 18”, and we changed the cards
above so that they read “17”, “Beer”, “22” and “Coke”, where the correct cards
to turn over are “17” and “beer”12.
This means that when we replace the abstract logical notions with a real world
example of the same relationship, but with the inclusion of a possible
"cheater" (i.e. 17 year olds drinking beer) then we can successfully
solve the task by hunting out the cheater. From this, Cosmides predicts that
cheater detection is an evolved trait that should only be evoked in social
exchange situations, where there is a requirement, benefit and cheater (in
accordance with the assumptions of game theory). So here we have a theory that
provides novel insight into human cognition and surpasses our folk wisdom, and
clearly passes the Grandparent and Lesser-Spotted Brown Gerbil tests. Can we
then be confident in our knowledge that this is an evolutionary adaptation?
Unfortunately, not yet.
The alternative explanation suggested by Sperber, Cara and
Girotto13 is that specific properties of the cheater detection scenario
employ a more general “exception-testing” rule – this would account for the
results in the cheater detection scenarios but it would not support an evolved
mechanism that was responsible for cheater detection. If these “properties”
could be identified and removed from the cheater detection task, and this
resulted in the effect disappearing, then the empirical support for Cosmides’
theory would also disappear. To test this they developed a three-part recipe to
ensure correct card selection:
- the P-and-not-Q case is easier to mentally represent than the P-and-Q case (underage drinkers versus legal-age drinkers);
- the P-and-not-Q case should be of more importance than P-and-Q case (breakers of the law versus followers of the law)
- the rule should be clear and unidirectional (there is no implication that legal-age drinkers should be drinking beer).
When looking at Cosmides’ culture-specific form of
the test (where the rule was “If a man eats cassava root, then he must have a
tattoo on his face” and the options “Eats cassava root”, “No tattoo”, “Eats
molo nuts”, and “Tattoo” were presented - with the "cheater" being
the non-tattooed man eating cassava root), Liberman and Klar14 noted some
inconsistencies between the cheater and non-cheater scenarios. Firstly, in the
noncheating scenario there is no specific violating rule (e.g. a man with no
tattoo eating a cassava root), secondly, the rule for cheating is strict and
exclusive, whereas the non-cheating scenario has reduced importance through the
use of qualifiers such as “usually” and “primarily”, and thirdly the
non-cheating rule is more easily interpreted as being bidirectional.
To eliminate these confounds, Liberman and Klar reversed the
conditions whilst maintaining the basic cheater detection structure and found
that detection of non-cheating was at 70%, whereas cheater detection was at 30%
- a perfect reversal of the results found in typical cheater detection
scenarios. In other words, even though there were still cheaters in the design
(non-tattooed men eating cassava root), by removing the biases from the setup
so that "cheater detection" was no longer the less difficult task,
subjects were less likely to search for them. With the effect completely
disappearing under these conditions, it becomes clear that the effect is not a
result of social relevance like Cosmides suggested, but is instead simply an
effect produced by experimental confounds. In other words, cheater detection is
a result of the “saliency” of the cheater in these experiments, and it is this
saliency that gives people the correct result, and not the presence of a
“cheater”.
THE EVOLUTION OF GULLIBILITY
This failure to properly adjust variables in an experiment
(thus reliably establishing causality) seems to be regular feature of
Evolutionary Psychology research, even when they meet the common sense tests
suggested above, so why do these factoids spread so quickly and become cemented
in popular thought? Do we have an evolved ability to be gullible of EP claims?
Most people would reject such an idea, so what is it that separates these
“ridiculous” claims from the ridiculous claims made by EP proponents?
It could be the persuasive logic and rhetoric that is often
employed as support for their theories, in particular are the two claims that
these behavioural traits are; 1) independent of global processes, automatic and
often not part of conscious thought, and 2) universal across cultures. On the
surface these two arguments appear to give us good reason to believe that a
behavior is a result of evolutionary processes, as both points imply that it is
instinctual or innate, and even though organisms have the ability to adapt over
their lifetime, there is the hidden assumption that such traits are too
“complex” to have been learnt. However, these arguments do nothing to support
their claims.
The first argument is countered by Gray et al. with
the example of riding a bike; it is clearly a specific process that functions
independently from global processes and generally we do not need to consciously
operate our bodies in order to successfully ride a bike. As a demonstration of
this, ask yourself what you would do if your bike started to tip to one side.
Most people reply that they would lean to the opposite side to right themselves
but this is incorrect as it would result in the person falling off their bike –
instead, when this happens the rider will turn the handlebars which corrects their centre of gravity. This meets the requirements of criterion (1), but
surely nobody would think that riding a bike is an evolved trait. Part of the
reason why we can easily reject such a claim is that the learning period is
obvious and when this learning phase is more subtle (like with language or walking) we
are sometimes fooled into reaching the wrong, or premature, conclusions.
Now we need to consider the second argument – that if
something is universal across cultures, then it cannot possibly be learnt. Is
this true? Of course not. Whilst it is necessarily true that an evolutionary
behavior would be universal across cultures, it is not true that a universal
behavior is an evolutionary behavior. This is because species-specific behaviors
can either be a result of an innate trait, or the result of shared
species-specific patterns of experience. In other words, if the environmental
factor that produces a particular learning experience is present across all
individuals of the species, then we would expect them all to learn the same
behavior. Again I turn to Gray et al. for an example, where they point
out that all humans, no matter what culture you look at, will eat soup from a
bowl and not a plate. The common environmental variable here is gravity and it
gives us a universal behavior – however, the literature on the evolved “eating
soup from a bowl” behavior is relatively scarce in the EP journals.
CONCLUSION
The common misconception spread by bad Evolutionary Psychology is that we have any significant understanding of evolved
behaviors in humans. This belief is pushed out year after year in books by
Pinker, Buss, Tooby and others, and it has now become more of an exercise in
politics rather than attracting interest in science and rational thinking.
Consistently these EP journals print articles discussing how women prefer the
colour pink because it reminds them of red berries from the hunter-gatherer
times of our ancestors15, ignoring the fact that
the preference for pink in women is an extremely recent trend from the last few
centuries (traditionally baby boys were dressed in pink and girls in blue), and
ignoring the fact that hunter-gatherer roles were not separated by sex; or
articles about how men are attracted to red lipstick because they look like
vaginas16. Even the more credible claims like
cheater detection, or men being attracted to women with low weight-to-hip
ratios17, are plagued by poorly thought out methodological designs
and an over-eagerness to ignore the relevant literature on possible learning
mechanisms that could account for the data – so much so that they earn
themselves the reputation of being ‘behavioral creationists’.
I started this post with the disclaimer that this is not a
broad attack on evolutionary psychology, and it is not a denial of the fact
that the brain is an evolved organ, and I want to reiterate those points. The
intention of this post is to highlight the flaws and inconsistencies in the
field, not to convince people to reject it wholesale but instead to increase
the skepticism surrounding this field. If a claim is made to the effect of “We
evolved to do X/ prefer Y/ etc” then the question we should ask is “What
research experimentally separated the learnt effects from evolved processes?”.
The misconception is not that behaviors can, or have, developed in organisms as
the result of evolutionary processes, but rather the belief that we can
prematurely accept these conclusions based on faulty logic and an overreliance
on (and misapplication of) evolutionary principles.
REFERENCES
1. Coyne, J.A. (2000). The fairy tales of evolutionary psychology: Of vice and men. The New Republic, 3 April, pp. 27-34.↩
2. Laland, K.N., & Brown, G.R. (2002). Sense and nonsense: Evolutionary perspectives on human behavior. Oxford, UK: Oxford University Press.↩
3. Gray, R. D., Heaney, M., & Fairhall, S. (2003). Evolutionary psychology and the challenge of adaptive explanation. In J. Fitness & K. Sterelny (Eds.), From Mating to Mentality (pp. 247-268).↩
4. Pinker, S. (1997). How the mind works. London: Allen Lane.↩
5. Tooby, J., & Cosmides, L. (Eds.). (1992). The psychological foundations of culture. In, J.H. Barkow, L., Cosmides, & J. Tooby, (Eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, (pp. 19-136). Oxford: Oxford University Press.↩
6. Gould, S.J., & Lewontin, R.C. (1979). The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist progam. Proceedings of the Royal Society of London B, 205, 581-598.↩
7. Lewontin, R.C. (1978). Adaptation. Scientific American, 293, 212-228.↩
8. Rosen, D.E. (1982). Teleostean interrelationships, morphological function and evolutionary inference. American Zoologist, 22, 261-273.↩
9. Williams, G.C. (1966). Adaptation and Natural Selection. Princeton University Press, Princeton, N.J.↩
10. Cosmides, L. (1989). The logic of social exchange: Has natural selection shaped how humans reason? Studies with the Wason selection task. Cognition, 31, 187-276.↩
1. Coyne, J.A. (2000). The fairy tales of evolutionary psychology: Of vice and men. The New Republic, 3 April, pp. 27-34.↩
2. Laland, K.N., & Brown, G.R. (2002). Sense and nonsense: Evolutionary perspectives on human behavior. Oxford, UK: Oxford University Press.↩
3. Gray, R. D., Heaney, M., & Fairhall, S. (2003). Evolutionary psychology and the challenge of adaptive explanation. In J. Fitness & K. Sterelny (Eds.), From Mating to Mentality (pp. 247-268).↩
4. Pinker, S. (1997). How the mind works. London: Allen Lane.↩
5. Tooby, J., & Cosmides, L. (Eds.). (1992). The psychological foundations of culture. In, J.H. Barkow, L., Cosmides, & J. Tooby, (Eds.), The Adapted Mind: Evolutionary Psychology and the Generation of Culture, (pp. 19-136). Oxford: Oxford University Press.↩
6. Gould, S.J., & Lewontin, R.C. (1979). The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist progam. Proceedings of the Royal Society of London B, 205, 581-598.↩
7. Lewontin, R.C. (1978). Adaptation. Scientific American, 293, 212-228.↩
8. Rosen, D.E. (1982). Teleostean interrelationships, morphological function and evolutionary inference. American Zoologist, 22, 261-273.↩
9. Williams, G.C. (1966). Adaptation and Natural Selection. Princeton University Press, Princeton, N.J.↩
10. Cosmides, L. (1989). The logic of social exchange: Has natural selection shaped how humans reason? Studies with the Wason selection task. Cognition, 31, 187-276.↩
11. Wason, P. (1966). Reasoning. In, B.M. Foss (Ed.), New horizons in psychology. Harmondsworth, UK: Penguin.↩
12. Griggs, R. & Cox, R. (1982). The elusive thematic material effect in Wason’s selection task. British Journal of Psychology, 73, 407-420.↩
13. Sperber, D., Cara, F., & Girotto, V. (1995). Relevance theory explains the selection task. Cognition, 57, 31-95.↩
14. Liberman, N., & Klar, Y. (1996). Hypothesis testing in Wason’s selection task: social exchange cheating detection or task understanding. Cognition, 58, 127-156.↩
15. Hurlbert, A. & Ling, Y. (2007). Biological components of sex differences in color preference. Current Biology, 17, 623-625.↩
12. Griggs, R. & Cox, R. (1982). The elusive thematic material effect in Wason’s selection task. British Journal of Psychology, 73, 407-420.↩
13. Sperber, D., Cara, F., & Girotto, V. (1995). Relevance theory explains the selection task. Cognition, 57, 31-95.↩
14. Liberman, N., & Klar, Y. (1996). Hypothesis testing in Wason’s selection task: social exchange cheating detection or task understanding. Cognition, 58, 127-156.↩
15. Hurlbert, A. & Ling, Y. (2007). Biological components of sex differences in color preference. Current Biology, 17, 623-625.↩
16. Elliot, A. J., & Niesta, D. (2008). Romantic red: Redenhances men's attraction to women. Journal of Personality and Social
Psychology, 95, 1150-1164.↩
17. Singh, D. (1993). Adaptive significance of female physicalattractiveness: Role of waist-to-hip ratio. Journal of Personality and Social
Psychology, 65(2), 293-307.↩
A good critique! Though I like several individuas in the field, I am amazed at how bad typical EP work is. A particular pet peeve, common in the literature, is the introduction of evolutionary story telling to justify a hypothesis that in no way require babbling about evolution. Often the hypotheses come out of folk psychology, and you could just say "people think X" so we investigated it, with nothing further needed.
ReplyDeleteFor thoughts on how EP can be done right... Can you get through to this paper?
Yes, I agree about how evo psych explanations are sometimes used as basically 'fillers' or even ways of selling research ideas, when (as you say) this isn't necessary at all.
DeleteThanks for the link to your paper. I've been reading through it today and I'm pretty sure I read it years ago and it contributed to my current standing on the field. I liked the way you divided the approaches up as essentially being evolutionary explanations vs evolutionary hypotheses and I think that's a great way of looking at it. What did you think of Gray's argument that the approaches can be summed up as 'Evolutionary Psychology' vs 'evolutionary psychology'? Is it a similar characterisation of the issue as what you presented?
Probably pretty similar. The problem is in finding a way to talk about the stuff of the last few decades without privileging it in some undue way (for example, by letting it have the capital letters). There has been continuous work integrating psychology and evolutionary thinking since Darwin, and frankly there was at least some before that. At some point psychologists need to start being more strict about what we let people get away with when labeling their systems.
DeleteBuss et al should NEVER have been allowed to arrogate the term "evolutionary psychology" to mean only the things they were working on.
I was glad to see you comment on this. I've always found EP a little hard to deal with since the proponents mine multiple disciplines. In spite of EP's name, as an anthropologist and due to disciplinary filters, I have always experienced EP as an anthropological problem, although one that bleeds out into other fields. Obviously Tooby is an anthro, and there is a long-standing streak of hyper-adaptationism in anthropology that contributed to EP. Even here, Ed Clint is in the process of launching himself into an anthropology career (although he was a psychology undergrad). I can deal with the various fields of anthropology, but the discussions tend to squeeze out into experimental psychology, evolutionary biology, neurobiology, sociology, etc. So it's definitely been informative to see the responses to Clint from people in different disciplines.
ReplyDeleteI feel for you in the evolutionary *psychology* complaint, but I am sort of relieved--I wonder if anthropologists only dodged that mud pie because "evolutionary anthropology" was already taken.
Thanks for the comment, Apxeo. The info on anthropology is interesting and I wasn't aware of the hyper-adaptationism in the field, although it does make sense after thinking about it. I think Clint is a classic example of one of the biggest problems in evo psych - people with a psychology degree and no understanding of biology trying to discuss the evolution of certain behaviors (or, perhaps worse, biologists with no understanding of psychology try to discuss the evolution of behaviors).
DeleteAnd you're right, psychology definitely drew the short straw by having its name attached to the evo psych research...
I don't know the current state of Anthro, but I know "Evolutionary Psychology" used to mean something a bit different for them. Louise Barrett had a textbook with that title a while ago, which was really a behavioral-ecology-of-humans book; i.e., there wasn't much in it to qualify as psychology proper. However, unlike those mucking around in psych, at least it was deeply grounded in evolution. (Incidentally, that is the same Barrett whose more recent book I have been gushing about recently, starting here.)
Deletehttp://whyevolutionistrue.wordpress.com/2013/07/07/a-defense-of-evolutionary-psychology-mostly-by-steve-pinker/
ReplyDeleteIt seems Jerry Coyne is actually quite the fan of evo psych.
Coyne's position has definitely softened over the last year or so, and he's stepped away from the extreme position that rejected all of evolutionary psychology and so now his position is not too dissimilar from the one I outlined in my post.
DeleteWith that said, I think Coyne may go a little further than me in that he seems to uncritically accept some controversial findings within evolutionary psychology, like the innate features of language, fear responses, and incest avoidance, and even attributes some non-evo psych findings to evolutionary psychology, like physical differences between races, sexual dimorphisms, and the development of lactose intolerance.
Regardless of his personal position on the issue, my arguments don't stand or fall on the comments of a single evolutionary biologist. That is, he could come out and claim that every finding within evolutionary psychology was valid and perfect, and it still wouldn't affect the validity of the arguments I discuss above.
Thanks for the comment.
Another great article.
ReplyDeleteI was wondering if you have read Sesardic (2003) and if so, what you thought of his own 3 criteria for a valid EP hypothesis. They seem to be based on Griffiths' criteria but are much more rigorous (as far as I can make out) i.e. they resolve all of the problems put to Griffiths'.
I read the article a few years ago and I think he makes a decent case for deciding whether something is a just-so story or a valid scientific hypothesis. If an hypothesis is presented with a viable recognised mechanism, makes predictions, and survives attempts to falsify it through the testing of possible confounds, then it can't be a just-so story.
DeleteWith that said though, that doesn't mean it's a valid or true hypothesis (as I think Sesardic himself says) and that's where I think the Grey criteria come into play.