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How Valid Is Evolutionary Psychology?

How a caricature of human nature leads evolutionary psychology astray.

Why do we find natural scenes like green fields, trees, and rivers beautiful? Why do people have an urge to gain wealth and power? Why do human beings fight wars? Why are human beings creative?

According to evolutionary psychology, the answers to these questions are linked to survival and reproduction. Evolutionary psychology explains present-day human traits and characteristics in terms of the survival value they possessed for our ancestors. These traits have survived because the genes they are linked to were ‘selected’ and have remained part of our genetic heritage. So in terms of the above examples, we find natural scenes attractive because for our ancestors they represented survival—lush vegetation, trees laden with fruits and nuts, rivers. People have an urge to gain wealth and power because, in prehistoric times, they enhanced their chances of survival and increased their reproductive possibilities. The instinct to wage war is so strong because prehistoric tribes of genetically similar people were in constant competition for resources with other groups. The creative instinct can also be seen as a way of increasing our reproductive possibilities—successful creativity increases our status and so makes us more attractive to potential mates.

It’s clear from these explanations (all of which have been put forward by evolutionary psychologists) that evolutionary psychology has a great deal of explanatory power—seldom has such a simple idea been used to explain such a wide variety of human behavior. This is probably the reason why the theory has become very popular, especially in the media and amongst non-scientists. As human beings, we have a strong need for explanation, to make sense of our behaviour and of the world around us. (This is part of the reason why religions are appealing to many people too.) However, the negative side of this is that, when theories do have explanatory power, we tend to become over-enthusiastic about them, and to over-estimate their validity. And I think this is the case with evolutionary psychology. Seldom has a theory gained such widespread support whilst being based on such shaky foundations.

Having said that, my problem with evolutionary psychology isn't so much with the theory itself, but with how it has been used to justify a particular view of human nature. After all, it makes sense to assume that we have inherited some behavioural tendencies from our ancestors, that some of the instincts we carry originated millions of years ago. As I suggest later, it might be possible to formulate an alternative interpretation of evolutionary psychology that doesn't make such grandiose claims, and is more in line with anthropological evidence.

Evolutionary Assumptions

As many observers have pointed out, evolutionary psychology is largely based on assumptions rather than evidence, and as such it is debatable whether it should be referred to as a 'science' (since its hypotheses are generally unfalsifiable). Its explanations of human behaviour are conjectures based on assumptions about what human life was like in prehistoric times. Adherents to evolutionary psychology tend to pick certain aspects of what they believe is ‘human nature’ and create stories to justify their development, based on the supposed benefits these traits would have had in early human history. Tellingly, these stores usually employ many qualifying terms such as ‘could have’ or ‘may have’, or adverbs such as ‘probably’ or ‘possibly.’ For example, the ‘innate’ selfishness of human beings could have been selected because, in prehistoric times, life was extremely hard, and the people who were most ruthless and least compassionate were more likely to hold on to food and resources themselves, and therefore more likely to survive. Compassion and a desire to share would have probably decreased the individual’s chances of survival. In a similar way, racism could have been ‘selected’ as a trait because altruism towards another group would have decreased a group’s own chances of survival. It was beneficial to deprive other groups of resources and power in order to increase our own access to them.

One fallacy of this is that ‘human nature’ is extremely nebulous and can be interpreted in a variety of ways. It’s easy to cherry-pick the characteristics which you think constitute human nature and invent your own ‘evolutionary psychology story’ to interpret them. Human beings are often collaborative rather than selfish and competitive; we are often benevolent rather than ruthless. There are many racist individuals, but there are also many people who feel empathy and inclusiveness towards other ethnic groups. Some evolutionary psychologists have even suggested that rape has an evolutionary basis: it can be seen as desperate attempt to replicate their genes by low status men who cannot attract willing sexual partners. However, what about the vast majority of low-status single men who would find the idea of rape barbaric and unthinkable? (As I write this, I’m thinking in terms of an ‘evolutionary psychology’ board game, with picture cards showing different human traits and squares moving upwards to selection and survival, and downwards to the evolutionary scrapheap.)

The latter example highlights another problem with evolutionary psychology: its underlying assumption that any human traits which have survived must have had some survival value. (This is referred to as 'panadaptionism.') If they hadn’t had any value, the genes related to them wouldn’t have been selected. This is why evolutionary psychologists feel obliged to make absurd and offensive justifications of behaviours such as rape and male domination. However, there are many prevalent human traits that don’t necessarily have survival value.

For example, perhaps the most striking aspect of human beings, in relation to other animals, is our consciousness. There have certainly been attempts to explain its development in adaptationist terms. The British philosopher Nicholas Humphrey, for example, suggests that having our own consciousness may have been evolutionary advantageous because it makes us feel that we are significant. We feel that we are ‘special individuals’ and that our lives have meaning, and so must have encouraged our desire to survive. Also, according to Humphrey, having our own consciousness may have helped us in terms of survival by giving us insight into other people’s thought processes, helping us to guess what they might be thinking or feeling. This helped us to compete against them, to ‘second guess’ or ‘out-guess’ them.

However, there are serious problems with this interpretation. Why should the feeling of being a ‘special self’ be advantageous when most other species survive well enough without (apparently) possessing it? And as the German philosopher Thomas Metzinger has pointed out, consciousness can easily be seen as a disadvantage. Firstly, self-consciousness causes psychological suffering, makes us liable to suffer from anxiety, frustration, and self-hatred. And on a wider scale, it can be seen as maladaptive, since we as human beings can’t seem to live in harmony with the earth, and are in danger of destroying the life-support of our planet, and hence killing ourselves.

In terms of one of the examples I chose at the beginning of this piece, it may make sense to suggest that we find lush natural landscapes beautiful because they are associated with abundant resources, and therefore represent survival. However, many people also find desert landscapes beautiful, when such a landscape would surely represent death. Many people find clear skies beautiful, and gray skies dreary, when in terms of survival gray skies would have been preferable (since they promised rain). Many people find the sea beautiful, which (although it obviously contains resources) is extremely treacherous.

Prehistoric Fallacies

Perhaps the most serious problem with these interpretations, however, is that they are based on erroneous assumptions about the human race’s past. The underlying assumption of most evolutionary psychologists is that the early period during which human traits developed was a hard and bleak struggle for survival. What is referred to as the 'environment of evolutionary adaptedness' was a time when human life was ‘nasty, brutish and short.’ It was—so they assume—a period of intense competition for survival, a kind of Roman gladiatorial battle in which only the traits which gave people a survival advantage were selected, and all others fell by the wayside.

But this is a crude caricature of prehistoric life. Until around 8000 BC, all human beings lived as hunter-gatherers. They survived by hunting wild animals (the man’s job) and foraging for wild plants, nuts, fruit, and vegetables (the woman’s job). When anthropologists began to look at how contemporary hunter-gatherers use their time, they were surprised to find that they only spent 12 to 20 hours per week searching for food—between a third and a half of the average modern working week! Because of this, the anthropologist Marshall Sahlins called (in his famous paper of that name) hunter-gatherers the ‘original affluent society’.

Strange though it may sound—the diet of hunter-gatherers was better than many modern peoples.’ Apart from the small amount of meat they ate (10%-20% of their diet), their diet was practically identical to that of a modern-day vegan—no dairy products and a wide variety of fruits, vegetables, roots, and nuts, all eaten raw (which nutrition experts tell us is the healthiest way to eat). This partly explains why skeletons of ancient hunter-gatherers are surprisingly large and robust, and show few signs of degenerative diseases and tooth decay. Hunter-gatherers were much less vulnerable to disease than later peoples. In fact, until the advances of modern medicine and hygiene of the 19th and 20th centuries, they may well have suffered less from disease than any other human beings in history. Many of the diseases which we’re now susceptible to (such as colds, the flu, measles, and smallpox) only actually arrived when we domesticated animals and started living close to them. In view of this, it’s not surprising that with the coming of agriculture, people’s life spans became shorter.

Prehistoric life was also relatively easy in the sense that warfare was uncommon. Although some observers (such as Steven Pinker) claim that war was rife in prehistoric times, many anthropologists dispute this, believing that warfare only become endemic once human beings switched to farming and began to live a settled life, leading to the formation of villages and towns. Before then, there was little sense of territory to protect, and populations were so small that there was little need for competition over resources. (1) Even modern-day hunter-gatherers are generally not territorial—they don’t think of a particular area of land as belonging to them and them alone, and don’t aggressively resist anybody who encroaches on it. (As the anthropologists Burch and Ellanna put it, “both social and spatial boundaries among hunter-gatherers are extremely flexible with regard to membership and geographic extent.”) It seems very unlikely that different groups were in continual conflict with another of resources. In fact, rather than being in conflict, contemporary foraging groups interact with each other a good deal. They regularly visit each other, make marriage alliances, and often switch membership. (For a longer discussion of this issue, see my book The Fall.)


There are many aspects of the typical ‘evolutionary psychology’ narrative which make no sense in terms of this anthropological evidence. The idea that human beings are naturally competitive and selfish makes little sense in view of the egalitarianism of hunter-gatherer groups. The anthropologist James Woodburn speaks of the “profound egalitarianism” of hunter-gatherer groups, while another anthropologist, Tim Ingold, speaks of their ‘moral obligation’ to share everything. Foraging peoples are also strikingly democratic, with no different classes or castes, which makes it difficult to imagine how an instinct to gain power and create hierarchy could have developed. Most societies do operate with a leader of some kind, but their power is usually very limited, and they can easily be deposed if the rest of the group aren’t satisfied with their leadership.

This egalitarianism extends to women too, which makes nonsense of the idea that male domination is somehow ‘natural.’ The fact that women provided the majority of a group’s food (as much as 90% according to some estimates) strongly suggests that they had equal status, since it’s difficult to see how they could have low status while performing such an important economic role. As Tim Ingold notes, in ‘immediate return hunter-gatherer societies’ (that is, societies which live by immediately using any food or other resources they collect, rather than storing them for later use), men have no authority over women. Women usually choose their own marriage partners, decide what work they want to do, and work whenever they choose to, and if a marriage breaks down they have custody rights over their children.

An Alternative Evolutionary Psychology?

In fact, it’s easy to imagine an alternative interpretation of evolutionary psychology, based on a more evidence-based view of the human race’s past. This type of evolutionary psychology would explain why altruism, sharing, and collaboration have become instinctive to human beings. The ‘story’ to explain this might be that the hunter-gatherer group’s ethos of egalitarianism was so strong that anyone who showed a strong desire for personal power or property would be ostracised from the group (which is actually the practice in some groups), and therefore be less likely to survive. Altruism was necessary as a way of demonstrating egalitarianism, to reduce one’s chances of being ejected from the group. Egalitarianism and altruism could therefore easily have been ‘selected’ as favourable traits. The difficulty with this kind of evolutionary psychology would be explaining why human beings are also prone to selfishness and status-seeking … But perhaps these could be explained away as forms of ‘disguised altruism.’

This sounds absurd, of course—but only as absurd as evolutionary psychology as it is normally interpreted is.

As I hinted above, the reason for the popularity of evolutionary psychology is probably the same reason why religions have been so popular throughout human history—a psychological need to make sense of the world, to possess an ‘explanatory framework’ which tells us who we are, where we are, how we came to be here and why we behave as we do. I’m not seriously suggesting that evolutionary psychology is a kind of religion—at least it has its roots in evidence-based science, even if its interpretations stray too far into conjecture and erroneous assumptions. But due to its simplicity and reductionism, evolutionary psychology is very appealing as the basis for an ideology or belief system. It is also appealing because the narrative of competitiveness and individualism which has been derived from it fits with the values of our society. The picture of early human life as a struggle for genetic success, with individuals and groups competing for access to limited resources, is a good metaphor for competitive capitalist societies—and was no doubt created in their image. A more egalitarian culture might well have come up with a more collaborative and benevolent model of human behavior—and would certainly have found evidence to justify this view.

(1) Lawrence Keeley’s book War Before Civilisation suggests several examples of prehistoric violence and warfare, but all of these are dubious, and have been dismissed by other scholars. For example, Keeley sees cut marks on human bones as evidence of cannibalism, when these are more likely to be the result of prehistoric funeral rituals of cleaning bones of their flesh. He also interprets highly abstract and stylised drawings in caves in Australia as depicting battles, when they are open to wide variety of other interpretations. In this way, as the anthropologist R. Brian Ferguson remarks, 'Keeley’s rhetoric exceeds his evidence in implying war is old as humanity.'

I am a senior lecturer in psychology at Leeds Beckett University, UK. I am the author of Back to Sanity and The Fall. Visit my website at

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