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Today Stefan Gehrig takes us on a magnificent journey through evolutionary psychology and its controversials. I am happy to extend my blog with guest posts, the more information on biology gathered here on livingdreams.tv, the better!

Explaining the presence by the past is the essence of evolutionary theory. If we consider the “strangeness” of humans as an animal species, the mysterious absurdity of their behavior and today`s sophisticated human culture, there is a lot to explain. However, seemingly, help has arrived. Grasping the mentioned phenomena with the classic scientific repertoire of evolutionary biology is the goal of a researcher’s clique, who call themselves evolutionary psychologists and who claim to contribute to describing the

“psychic unity of mankind – that is, a universal and uniform human nature” (1)

which means nothing less than elaborating evolutionary scenarios which let us understand why we think, behave and feel the way we do and thereby create the world we live in. The roots, they say, lie in the Stone Age. So far, so good.

I recently read a book that basically is a massive critique of the described science of evolutionary psychology (its methods, its framework, its conclusions) as it is conducted by the majority of evolutionary psychologists. The book “Adapting Minds” by David J. Buller truly picks their scientific paradigm in pieces. And that is where the fun starts. I would like to share the controversy that arises from evolutionary psychology vs. David Buller with you – from the perspective that I gained by reading Buller’s critical response volume. The whole argument informs a lot about biology, about evolution and about how (not?) to do research in sexy behavioral issues like What do women/men really want?

Do our behavioral roots lie in the Stone Age? source

Evolutionary psychology vs. their critiques

So, how did all the conflict come up in a natural science, which are due to their reliance on empirical data (wrongfully) expected to leave little space for fundamental disputes?

The broad applicability and seeming (!) simplicity of the general biological principle – evolution – has universalized its use as well in horribly inaccurate ways (which, of course, include all pseudodarwinian argumentations about social, physical or racial superiority that history has proven so bitterly wrong) as in exciting sub-fields of other sciences: today there are people performing evolutionary economics, evolutionary medicine or, and here we got back to the battlefield of this article, evolutionary psychology – all borrowing, or at least claiming to borrow, the evolutionary way of thinking from evolutionary biology, which is, as mentioned, the leading paradigm of modern life science. Nevertheless, there is a lot to argue about how and whether evolutionary principles are applied in a reasonable way, especially when it comes to such ambitious endeavors like the ones of evolutionary psychology, who want to explain our mind by evolution.

Scientists taking part in this enterprise comprise anthropoligists, psychologists, biologists and linguistics which have comprehensively set up a theoretical framework that claims to be

“psychology informed by the fact that the inherited architecture of the human mind is the product of the evolutionary process” (2).

Our brain – only an assembly of infelxible adaptations throughout  homonoid evolution? source

Certainly right in the fact that the underlying anatomy and functioning of our behavior and mind – namely, our central nervous system – is the outcome of evolutionary processes and is therefore to some degree affected by common evolutionary concepts like variation, selection, drift, adaptation, fitness and heredity, the program of evolutionary psychology, as defined by their main operators like John Tooby, Leda Cosmides, Steven Pinker, Don Symons or David Buss , goes further: evolutionary psychologists state that the central structure of our mind is universal among human individuals because it consists of adaptations which respond to the diverse problems that our ancestors had to solve during the main period of hominid evolution, the Pleistocene. Our brain is hence the mere assembly of all these adaptations. They state we can study these antique adaptations today with well designed experiments. Easily put, evolutionary psychologists suggest that behaviors and psychological mechanisms that made certain individuals among our ancestors have more offspring in their hunter-gatherer communities than others are still hard-wired in our today`s brains because the genes that code for it got selected back then. Most drastically the perspective of evolutionary psychology is shown with examples of their findings.

Evolutionary psychologists belief to have demonstrated or at least well argued that

– men prefer young and “femalish” women during partner choice (and all body characteristics that indicate it) because of higher fertility

– women prefer wealth in men during partner choice because of potentially better child care through more ressources

– men feel jealousy towards betraying wives because they could spend resources on another man`s child and hence men care more for sexual fidelity than for emotional fidelity

– women feel jealousy towards betraying husbands because they could lose the long-term parental investment of their husband and hence women care more for emotional fidelity than for sexual fidelity

– stepparents are more violent to stepchildren than genetic parents are to their own offspring because they don’t increase their own fitness

– we solve puzzles and logical exercises faster and more accurate when they invoke a scenario in which we might have been cheated by someone else than when the puzzle is not bedded into a story of social cheating because our ancestors profited from that skill of “social intelligence”

– emotional tendencies to marriage or monogamy have evolved in the human lineage because by that men ensure paternity certainty of the born children and women ensure care for the child (“reproductive contract”)

– mediocrely attractive women seek to betray their husbands with more symmetrical men to capture better genes outside the relationship

…and so on.

Are our minds readily evolved? Is there a normal way of functioning?

Darwinian principles – for sure the cradle of life, but how far can scientists simplify them without abandoning the truth? source

In all cases, evolutionary psychologists provide their readers with elaborately made-up arguments why darwininan principles (the fostering of one`s own genes) should lead to the observed behavior – although, they say, our way of thinking does not explicitly employ this logic. A simple visual example: we might fall in love with a rich (or potentially rich guy, not because we think that he will provide good parental care and thereby increase our fitness, but still, whatever we think (“love needs no explanations”), his signs of wealth are the reason for us to develop the emotional bond. The experiments evolutionary psychologists conduct often seem to affirm their theories and the above-mentioned hypotheses. The methods thereby applied reach from the survey of historical demographic records to putting men into Burger King-costumes to make them stimuli of low resource-partners and watch how women judge them on a scale attractiveness.

Despite the controversial content of their findings and doubtable methods, one can draw some far-reaching implications from their naked theory already, that describe evolutionary psychologist’s view of the human mind:

–  Our minds are readily evolved, because the Stone Age is over.

–  We are not psychologically adapted to our present environment and the modern way of life, but to a past environment

–  Our minds are to a determining amount naturally and sexually selected.

–  There is a normal way for a human mind to function and hence a normal behavior, because the mind consists of species-typical adaptations.

–  True cultural and variation is solely based on the variation of input to our “universal psychological adaptations”.

–  We possess many hundreds problem-solving modules in our brain and no general intelligence, with all modules suited for single problem domains. That means, we lack a general problem-solving mechanism, because the psychological and behavioral solutions evolved separately for the separate adaptive problems of our ancestors (e.g. with whom to mate? With whom to build a social alliance? How to interpret the behavior or expressions of others?).

Though, as visible, based on a massive theoretical fundament, though often logical on first glance, though from time to time making valuable contributions to our understanding of human cross-cultural behavioral universals, though clearly sticking to natural science and though being published in high-ranked journals on a regular basis: not only that their studies often suffer from (methodo-)logical flaws (e.g. although investigations  showed a higher rate for maltreatment of stepchildren by stepparents than by genetic parents, it were only less than 1 % of all stepparents at all maltreating their children: how can we then speak of a universal tendency then? And how can the theory explain that adopted children get maltreated the least at all?), in addition, a variety of the basic assumptions of evolutionary psychology is in contradiction, or at least  with biology itself, some of which are more, others much less obvious:

– Evolution goes on. Why should we be formed to a greater amount by the Pleistocene environment than by the rapidly and massively changing environment we face today? We can expect intense and varying selection pressures due to our species-typical extreme dependence on social life, social signals and social behavior. Nothing is more unstable than social environments, because the responding organisms itself create it and hence psychological evolution should by highly variable too.

– There is individual variation all around the globe and in every population. It is not logical that there can only be one adaptive phenotype and one general way our minds work. Instead, differential personalities can arise through trade-offs (i.e. being less a, but therefore being more b), through strongly fluctuating pressures and mechanisms like frequency-dependent selection and thereby nevertheless harbor equal fitness despite being different. Polymorphisms occur in a multitude of species and are no contradiction to evolutionary thinking. For example, there is comprehensive scientific work explaining introverts and extroverts as too extreme personalities in a continuum of different adaptive coping strategies.

– There does not have to be “natural laws” about humans (and hence a “human nature”), as humans are not a natural kind, means a natural category, by itself. Humans don´t necessarily share essential attributes at all that make them “more” or “less” human, because species are biologically defined by their genealogical connection and not by common attributes that define them.

– Adaptation is only one of the driving forces of evolution. Traits can evolve and occur by adaptation just as by drift and by being neutral to fitness. Thus, why shouldn’t our minds be made up to high degree by traits that are not a response to any fitness-related problem at all?

– Evolution is not goal-oriented. Evolution, contrarily to a wide-spread misbelief, does not produce optimal adapted organisms. Evolution only works with the substrate of realized variation within a population. Consequently, there are adaptive problems that an organism does not have to solve (like the problem of flying for Homo sapiens) and there are potentially better suited adaptations to the real problems faced, than the solutions that evolution actually produces. Due to this, arguing in a purely adaptionist way does not capture the picture of evolution, which is not an optimalistic but a historic process.

– Plasticity can be adaptive too. Why should there be fixed modules of how to solve stone age- problems like mating and parenting, when plastic behavior, that can be rapidly adapted to the environment, can be at least as beneficial as innate behavior in some circumstances? The way our neural network responds to thoughts, memories and actions highly points on plasticity rather than on stability as developmental mechanism during lifetime.

”If you think something is wrong if it’s unnatural, you’re not going to think much about flying in a plane or refrigerating food or surviving a severe infection. More generally, our bodies and brains have evolved for reproductive success, but we can use these brains to choose our own destinies. Nothing moral necessarily follows from the facts of biology.” image source

Psychological mechanisms might not emerge as simple as generally believed

These appraisals are some major challenges for evolutionary psychologist`s way of perceiving the human mind and their ambition to describe it by adaptive functioning.

Although the topics evolutionary psychology discusses are of broad public interest and, I want to stress that, an evolutionary, natural science-based approach towards phenomena of culture, human behavior, human mind and human sociology is highly appreciable, because they surely are biological attributes, or, as philosopher David Buller puts it in his book:

“the practices that constitute human cultures differ only in degree of complexity, not in kind, from the web-spinning habits of spiders” (3),

the way evolutionary psychology research is conducted at times is more than just arguable. One could desire a fresh way of thinking in this field, more than just a stolid sticking to old paradigms and to deriving simplistic human universals from non-compelling experiments. Our psychological mechanisms, whatever they are, for sure not simple and not universal.

And, even more important, it is crucial to bare in mind that nobody of us, no matter on which side, should make the fallacy of confounding human behavioral biology with human ethics. Though we might be equipped with some psychological and cognitive traits that are not under our deliberate control, decision-making stays – or becomes even more – an individual challenge for every one him- and herself.  Psychologist Paul Bloom, also contributing to a chapter in the evolutionary psychology textbook Adapted Mind, elaborately summarizes this relationship:

”If you think something is wrong if it’s unnatural, you’re not going to think much about flying in a plane or refrigerating food or surviving a severe infection. More generally, our bodies and brains have evolved for reproductive success, but we can use these brains to choose our own destinies. Nothing moral necessarily follows from the facts of biology.” (4)

I hope this short overview could raise your interest in the exciting debate of evolutionary psychology vs. their critiques and our intense desire to understand ourselves. My standpoint is of course biased by the critical book that I recently read (D. Buller, Adapting Minds) and I am open to discussions. Buller’s book too is not persuasive in every of its details and the unhandiness of the topic often prevents clear and complete argumentation.

For those of you that want to get deeper into the topic: The classical scientific volumes of evolutionary psychology, that also contain the mentioned examples, are: The Adapted Mind (Barkow, Cosmides, Tooby), Oxford University Press 1992, and Evolutionary Psychology: The New Science Of The Mind (Buss), Allyn & Bacon 1999. The researchers named in the text also have long and interesting publication lists. The detailed critique, that this articles refers to, is written David J. Buller and is: Adapting Minds, MIT Press 2005.

Quotes:

(1) The Adapted Mind (Barkow, Cosmides, Tooby), Oxford University Press 1992, p. 79

(2) The Adapted Mind (Barkow, Cosmides, Tooby), Oxford University Press 1992, p. 2

(3) Adapting Minds (Buller), MIT Press 2005, p. 422

(4) Course Introductory Psychology, Yale Open Courses, 2007