Limits of Evolutionary Psychology

Evolutionary psychology is a school of psychology that relates human traits and behaviour to how humans evolved on the plains of Africa over hundreds of thousands of years; it is based around reproduction and the propagation of useful genes. The term “survival of the fittest” only applies to the point where individuals need to be fit and healthy to reproduce. In fact reproduction is the most detrimental and risky thing any one individual can undertake. For males it means competing with other males, it might involve travelling long distances alone all of which could, and often did, result in death. For females, could you image giving birth without any medical assistance in the bush, and that is before taking into account the risk of being less mobile for several months whilst pregnant with predators all around. Evolutionary psychology does explain quite nicely many behaviours and traits that are so very detrimental to health and fitness in modern humans. It explains why we love to eat fat and sugar, why young men are so reckless and are over represented in road fatalities for instance.

Of course evolutionary psychology does not explain all human behaviour. In response to the many comments about my earlier blogs on how evolutionary survival strategies determined different roles for males and females, I can say categorically  that ten thousand years ago humans did not wear clothes and so evolutionary psychology has nothing to say on who does the ironing. Who does the bulk of domestic chores is purely a determination of culture. The military, which is very male dominated, seems very keen on clean well ironed uniforms and neatly made beds, which proves men can complete these tasks just as well as women.

Also, some groups have tried to link evolution to race. From an evolutionary psychology perspective there is no such thing as race. Often this will be met with statements link ‘but I can see obvious differences between races’. Ok, let’s consider an example; a clansman from central Africa is very tall, dark skinned and has frizzy hair whilst a Japanese person is short, paled skin and has straight hair. Whilst it is true that if you consider people across vast distances you will see differences, what this argument does not take into account is the myriad of variations in people as you travel between Africa and Japan, say. As we move north from Africa we begin to see skin colour lightening with a decrease in the intensity of sun light. The further north we go the quicker this change occurs, due to the increasing angle of the sun. It is impossible to pick a point where people change skin colour from dark to light. Height is also interesting; it is the perfect example of an interaction between genes and environment. At the end of WWll the average height of Japanese males was estimated at 160 cm, today the average is 171 cm. A combination of better diet, better medical care and a preference for height in a partner have all contributed to making people much taller very quickly. So the difference in height between the African clansman and a Japanese person is better accounted for by culture and diet interacting with genes than by a declaration of race.

One final word on evolutionary psychology, there are some things that evolution explains very well. From a bio-mechanics point of view walking on four legs is much easier on a body than walking on two legs. Humans pay a big price for walking on two legs, our backs are more prone to stress, human knees carry twice the weight of a creature on all fours and our shoulders have become so flimsily that they dislocate easily. But of course the gains of walking on two legs were huge, for instance we developed very flexible hands. Most primates can stand on two feet and have extremely strong bodies, they can hang form a single hand or foot for hours, but they cannot stand for very long. That is because to stand you need very well developed gluteus maximus muscle (a strong bottom) and core muscles to support the back. It took countless generations, thousands of years, for human to develop the ability to stand. It only took a few decades for humans to send all day sitting down, hence all the back and knee problems in modern society. So evolutionary psychology can be very useful but we need to careful to use a scientifically supportive approach.