Evolutionary Psychology

“In many ways, the human mind is misaligned with the working world, and with the modern world in general”

The goal of research in evolutionary psychology is to understand and map the human mind and brain. Steve Stewart-Williams, Associate Professor of psychology at Nottingham University Malaysia Campus, Semenyih, Malaysia, explains the framework and provides an outlook on the opportunities of research in evolutionary psychology for modern society.

Prof. Stewart-Williams, the Standard Social Science Model, which traces back to the British Empiricists Locke and Hume, basically proposes that the human mind is a tabula rasa learning system shaped by experience. Even if most people take this for granted, why is this view defective?

Because it’s not true! Like it or not, humans aren’t blank slates. Many things that social scientists traditionally explained solely in terms of learning and culture turn out to be grounded in our basic evolved nature. This includes a diverse collection of emotions, from fear to romantic love to jealousy. It includes average sex differences in aggression, parental inclinations, and interest in casual sex. It includes various mate preferences and an aversion to incestuous mating. And it includes a tendency to favour relatives over unrelated people. All these traits and inclinations are found in every known human culture, even when the culture tries to eliminate them, and all are found in evolutionarily comparable nonhuman animals as well. This suggests that they’re part of our evolved endowment, rather than just products of the local culture.

It is true that humans rely more on learning and culture than any other animal. And unlike other animals, we can live in a huge number of different ways – as hunter-gatherers on the African savannah, for example, or investment bankers on Wall Street. In that sense, we could argue that humans actually are blank slates to some degree. But the slate is far from entirely blank, and a complete science of human nature must take this fact into account. (Steven Pinker’s book The Blank Slate is very good on this issue.)

Evolutionary Psychology is a framework, inspired by Darwin, which views the human mind and brain as the product of evolved cognitive adaptations shaped by natural selection. Could you briefly explain this approach?

Evolutionary psychology takes conceptual tools from evolutionary biology, and uses them to shed light on the human mind and behaviour. Most notably, it takes an adaptationist approach to the human mind. To see what this means, consider how we use the adaptationist approach to explain anatomical features in other animals. Why do crocodiles have sharp teeth? Simple: to kill and devour their prey. Why do antelopes have fast legs? Simple again: to escape the clutches of hungry crocodiles and other predators.

Evolutionary psychology takes this explanatory framework and applies it to the basic constituents of the human mind. Why do people experience fear? Simple: Fear motivates us to escape threats to life and limb – crocodiles, heights, strangers in dark alleys. Why do we experience lust? Simple again: Lust motivates us to engage in certain activities that typically result in the production of offspring (or did, at least, before the invention of reliable contraception). Why do we experience parental love? Because parental love motivates us to care for our kids. And so on.

Critics of evolutionary psychology sometimes argue that evolutionary psychologists think that everything is an adaptation. But that’s not true; evolutionary psychologists have various non-adaptationist explanatory tools up their sleeves as well. One is the mismatch hypothesis. This is the idea that some traits, rather than being adaptations, are products of the mismatch between the environment in which humans evolved and the one we inhabit today. The classic example is obesity. Obesity is clearly not an adaptation. Instead, according to evolutionary psychologists, it’s a result of the fact that we now live in an environment very unlike the one in which we spent most of our evolutionary history – an environment in which we can all-too easily eat more sugar, starchy carbs, and processed foods than we should, and fail to get enough exercise.

Another non-adaptationist tool is the byproduct hypothesis: the idea that some traits are not adaptations in and of themselves but are byproducts of other traits that are. Pornography is one example. Like obesity, the human penchant for porn is clearly not an adaptation. Instead, it’s a byproduct of the fact that we’ve evolved to find certain visual stimuli sexually arousing. This tendency is notably stronger in men than in women, which helps to explain an obvious sex difference in the consumption of porn. Thus, the behaviour in question is not a direct product of evolution, but an evolutionary perspective sheds light on the phenomenon nonetheless.

According to this, the human mind is designed to solve the everyday problems of our hunter-gatherer ancestors. How was the environment in which human minds evolved in?

Well it’s not just about our hunter-gatherer ancestors. In the early days of the field, evolutionary psychologists did often put a strong emphasis on our hunter-gatherer past. The rationale for this was that, for most of our evolutionary history, we lived as nomadic hunter-gatherers in the African savannah, and that we only started developing agriculture and civilizations in the last 10,000 years. 10,000 years is a mere blink of an eye in evolutionary terms, they argued, and thus we’ve done very little evolving in that time. Modern humans are basically hunter-gatherers in suits and skirts, driving cars and living in suburbs and tower blocks. To put it in technical terms, according to the early evolutionary psychologists, our environment of evolutionary adaptedness (or EEA) is the Pleistocene savannah, not our modern environment.

Since those early days, though, scientists have discovered that evolution can sometimes happen extremely rapidly, and that human evolution has actually sped up since the advent of agriculture. Thus, we’re not simply hunter-gatherers in the fast lane; we’ve changed a fair amount. To give one well-known example, in the last few thousand years, various human populations have evolved to drink milk throughout the lifespan, rather than just in infancy. This discovery, and others like it, should make us wary of putting too strong an emphasis on hunting and gathering in the Pleistocene savannah.

In my view, the best way to think about the issue is to throw away the notion of the EEA as a single place and time. Instead, we should say that each adaptation has its own EEA, and that the EEA for any given adaptation may or may not fit within the borders of the Pleistocene savannah. The EEA for vision, for instance, long predates the Pleistocene and still exists today. The EEA for life-long milk-drinking, on the other hand, came only after certain human groups started herding animals such as cows, goats, and camels. No doubt, the selection pressures associated with Pleistocene hunting and gathering loom large for our species. But they’re not the be-all and end-all.

I should mention, by the way, that this way of thinking isn’t a radical rewrite of evolutionary psychology. It comes from two of the founders of the field, Leda Cosmides and John Tooby, and can be found in some of their earliest writings.

Numerous surveys postulate that the requirements of the modern working world, e.g., high pressure to perform, multitasking and permanent accessibility, cause mental illnesses, e.g., burnout, particularly in the industrialized countries. Isn’t our brain made for the modern working world’s requirements?

In many ways, the human mind is misaligned with the working world, and with the modern world in general. I’ve already mentioned that the obesity epidemic is a direct consequence of the fact that we live in an environment quite unlike the one we’re “designed” for. And there are plenty of other examples. The evolutionary psychologists Jennifer Hahn-Holbrook and Martie Haselton, for instance, have made a convincing case that postpartum depression is largely a consequence of evolutionary mismatch. In traditional societies, new mothers almost always had lots of social support, a diet high in Omega 3 fatty acids, and plenty of exercise and sunlight. As a result, they rarely succumbed to postpartum depression. These days, however, women are often in a very different boat, and postpartum depression is often a very real threat. Other possible products of evolutionary mismatch include kids’ antipathy toward school, psychiatric conditions such as ADHD, and the fact that we fear snakes and spiders more than we do cigarettes and fast cars, even though the latter pose more of a risk to us in the modern world.

Having said all this, it’s worth remembering that our minds made the modern world, and thus that in many ways, the modern world is well suited to our needs. One reason that Microsoft Windows and Apple iPhones are so popular, for example, is that people find them easy to use, and the reason for that is that these products interface well with the way the human mind naturally works. Lots of culture does, for the simple reason that if it didn’t, it would never have gone viral in the first place. In effect, selection in the realm of culture favours cultural products that mesh well with our evolved biases and dispositions.

It’s also worth remembering that mismatch isn’t always a bad thing. Sometimes, in fact, it’s a very good thing. The best example I know concerns child mortality. In the bad old days, a high proportion of children died long before they reached adulthood, with the first year of life being particularly precarious. In the last hundred years, however, we’ve largely solved this ancient problem – not just in the West but in most nations. The fact that the vast majority of our children now make it to adulthood is a product of evolutionary mismatch. But it’s also one of our greatest accomplishments as a species, and one of the largest steps we’ve taken toward improving the quality of human life.

What opportunities will arise from evolutionary psychological research for modern society in the future?

That’s a tough question! More than most areas in psychology, evolutionary psychology is a basic science, rather than an applied one: It aims to explain the mind and behaviour, rather than to find ways of improving the world. Still, it’s hard to imagine that our growing understanding of our evolved nature could fail to inform our efforts to improve the world we live in. One way it might do this is by helping us to identify practices and policies that are unlikely to work, or which might even backfire, because they were inspired by an inaccurate view of human nature. For example, if nausea and vomiting during early pregnancy (NVP) is an adaptation designed to prevent women from ingesting harmful toxins at a time when the fetus is especially vulnerable, then attempting to eliminate these “symptoms” may place the fetus at risk. If fever is an adaptation for killing invading pathogens, then lowering a mild fever may prolong the illness. If men and women differ, on average, in their natural interests and preferences, then trying to force a 50:50 sex ratio in every desirable occupation might diminish aggregate happiness, rather than enhancing it. And if certain sex differences are part-and-parcel of human nature, rather than products of discrimination or sexist socialization practices, then attempting to eliminate them might be as misguided as trying to force gay people to be straight or lefthanders to use their right hands.

Or maybe not! There are good arguments on both sides of all these contentious issues. At the very least, though, an evolutionary perspective is valuable in that it raises these sorts of questions – questions we might otherwise never have thought to ask.

Interview: Sebastian Kaiser

Further information:

I discuss these and related issues in detail in my forthcoming book, The Ape That Understood the Universe. My personal website is http://www.stevestewartwilliams.com/

Picture Credit: Jane Stewart-Williams


Steve is an associate professor of psychology at Nottingham University Malaysia Campus. Before taking up his current position, he was a Senior Lecturer at Swansea University, and before that he spent two years as a postdoctoral fellow at McMaster University in Canada, working in the lab of Martin Daly and Margo Wilson. He did his Ph.D. in psychology and philosophy at Massey University in New Zealand.

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