The science of evolutionary psychology is the study of human nature. Humans have an innate nature with which they are born. All around the world, people act in very similar ways. When we are successful we feel good, when we fail we feel bad. No one needs to teach us to feel bad when we fail. This comes naturally to us. Humans feel emotions despite a total lack of training. Similarly, no one teaches us to operate our ears or eyes, or other sophisticated parts of our bodies. Instinct takes over, and we feel and act all pretty much the same.
It used to be argued that a human baby was a blank slate, on which society, culture and individual life experience wrote. The way each person turned out was a product of nurture, not Nature. Whereas it was widely accepted that people would grow arms and legs in particular shapes because they were destined to do so from birth, many people believed, or at least preferred to believe that they believed, that the brain was different. Even though the brain is an organ which, like all other organs, is grown according to the instructions of the genes, the mind created by the brain was by many claimed to be above the mundane pre-determination of a person’s genes, and that it was special, having no innate qualities whatsoever, and merely a product of upbringing. That this assertion was and is patently ludicrous, did not, and does not, put some people off asserting it. Many of these people are called "social scientists", and have a strong vested interest (their jobs and respect) in making other people accept that they are right.
One tactic used by social scientists is to claim that evolutionary psychologists are saying something that they are in truth not saying. This is that we believe that a person’s character, behaviour, and abilities are shaped solely by the genes, and that upbringing has no effect. This too is patent nonsense, and NO evolutionary psychologist believes this. As Matt Ridley put it, this is like arguing that the area of a field is dependant on its length but not its width.
The best analogy I have found for evolutionary psychology is the undeveloped photograph. I hope that this makes what we believe clear to you. Imagine a foetus in the womb. The brain of this foetus is like an exposed but undeveloped photograph. Let us for the sake of argument say that the exposure was of a picture of the Taj Mahal. The foetus leaves the womb and becomes a baby. Perhaps the baby will not be fed and will die. This is like the film being exposed to lots of light, and the picture’s being destroyed. If the baby is fed and looked after, it will become a child, and grow. Just as food feeds the body of the child, life experience develops the mind. Life experience is like developing fluid, and fixative, and water. Unlike the methodical actions of a laboratory photo-technician, life is more random and disordered. Developing fluid is splashed rather haphazardly on the photograph. Some parts of the picture, such as the sky above the main dome of the building, get splashed with fluid which brings out the greens, but not the blues. Other parts, such as the left hand corner tower, do not get any developer splashed on at all. Some parts get developed, but then water washes off the result before the fixer can preserve that part of the picture. The photograph we end up with is like the adult person. Perhaps that person was born with the genes which gave them the potential to be the world’s greatest ever tennis player, but they never picked up a racket until it was too late. Perhaps they were born with a strong inclination to be sad, but had such a pleasant life, that this aspect of them never developed as much as it might have.
By splashing developing fluids, water, and fixatives onto that piece of film, we can create many different versions of the picture. The sky may be tinged with an unrealistic green, some parts of the picture may be blurred, and perhaps it will not be the best picture of the Taj Mahal, but, and here is the crucial bit, no amount of random splashing of fluids will turn that exposure into a picture of the Eifel Tower, or Sydney Opera House, or the Hanging Gardens of Babylon. A person cannot be brought up to be the world’s best tennis player, if they lack the basic innate ability to play the game well. A girl brought up as a boy will still end up having girlish instincts. A boy cannot be brought up to have the instincts of a squirrel. You cannot teach someone never to feel anger or fear. Humans have an innate nature. Upbringing of course affects how we turn out as adults, but upbringing only has what we are born with as its raw materials.
When the people who lived in the central parts of New Guinea were discovered in the 1930s, they were amazed. The people there had been so isolated for so long, that they all believed that they were the only people in the world. They, who had had no contact with any other culture for countless generations, were like us. The men who made first contact with them could read the expressions on their faces. When they were amazed, the folk of New Guinea raised their eyebrows, as we do. When they smelled a disgusting smell, they screwed their faces up in disgust, as we do. When they were happy, they smiled, as we do, and pretty much the same things made them happy: good food, good company, good conversation, sex, warmth, and success, while the same things made them miserable: rejection, failure, cold, hunger, and loneliness.
People have an innate nature. Evolutionary psychology seeks to discover that nature, and to work out why it is that way. We have an innate nature, because we have inherited genes from our most successful ancestors. The instincts and emotions which people of the past had, affected their success in surviving and breeding. We are the descendants of the people who both survived and bred.
The phrase "survival of the fittest" was never used by Darwin, and it confuses many people who don’t fully understand evolution. It suggests that a creature needs to be fit to survive, needs to defeat rivals to survive, and that survival is the goal of life. In fact, a creature that survives by what ever method may be successful. Many of our ancestors must have been good and kind by nature, since there are good and kind people alive today. Those good and kind ancestors of ours did not just survive for a while; they did something far more important for evolution: they had children. A man who is fit and lives to a ripe old age, but who has no children, does not become anyone’s ancestor. Reproduction is the key.
So, an evolutionary psychologist first has to identify some aspect of human nature that is universal - common to all cultures. Once he is satisfied that this trait is universal because it is innate, he has to think back to the time of our ancestors, and work out how that trait might have helped those people become our ancestors. It is a fascinating pursuit. Humans evolved into the way we are today, over a period of about two million years, during which they were hunter-gatherers, not farmers or city dwellers. Our instincts today may often appear to be disadvantageous, but that is either because we do not properly understand them, or because we are living in a way which is so unlike the way our ancestors lived, that the instincts we have inherited are inappropriate.
This is a brief introduction to evolutionary psychology, but I hope that it makes it clear enough for you to follow the arguments in the essays in this web site.