During much of my higher education, I haven’t enjoyed the small-talk question acquaintances invariably ask: what’s your major? Until last May my answer was “psychology”, which led them to instantly conclude I wished to be a clinical therapist, that being the only existing job within the domain of psychology. At that point I would explain my interest in research, my ambition to put people in a giant rat maze and perhaps to shock then with electrodes, for science. In anticipation of these conversations, I much enjoyed being “undeclared” during my sophomore year during which I would tell people I was a freelance learner and that I found majors fascist and suffocating.
Antisocial cheek notwithstanding, I knew precisely what I wanted to study a full decade before I arrived at university: evolutionary psychology. Whenever I tell someone that, they almost always ask “What is evolutionary psychology”? I suspect this is not an issue for law or med students. Regardless, perhaps an explanation is in order for the curious readers of this network.
Square one: Darwin
Evolutionary psychology is a child of evolutionary biology, so we have to start with Darwin’s grand hypothesis. Darwin was the first to observe, document, and articulate that organisms have traits that are heritable and that some traits lead to more surviving offspring than others. These traits become more numerous in a given population and when this happens enough times for enough traits, a species can change into one or more new species. In a high school biology class, the most common examples of such traits are physical characteristics: giraffes with longer necks are able to reach more leaves, and thus bear more offspring than those who are less-well nourished. Moths with coloration similar to local flora are less apt to feed the local bird population and so on. Is that all that we mean by trait? What is a trait?
Acting out
A trait is any observable aspect of an organism. This includes structures like bones or gills, but also behavior. Now a given trait might be genetic (and fodder for selection) or not. An amputee is the victim of circumstance, not genetics, even though their phenotype may include one-armed-ness. That said, behaviors are frequently biological traits and it could hardly be otherwise. What good would it be to have wings, and not have the neural control program capable of learning to use them to fly? Why would it matter for a Peacock to have dazzling, iridescent plumage if the peahen could not evolve useful sexual preferences? Even the giraffe’s over-hyped neck would be totally useless if giraffes didn’t also have brains that found leaves to be delicious. In short, animals have a nature. Birds fly, fish swim, and humans worry about whether the milk has gone bad because they’ve evolved brains that allow them to.
These are not new observations. Darwin himself wrote about animal and human psychology, primarily in his The Expression of the Emotions in Man and Animals. He noted that human emotions are accompanied by reliable, carefully choreographed patterns of muscle contractions: facial expressions. Even babies born blind and deaf, who’ve never seen a smile or frown, smile and frown when happy and sad. His observation was far-sighted to say the least. The obvious correlation between subjective, situation-dependent feelings and reflexive biological muscle contractions somehow remained controversial, even a century after Darwin.
The discovery channel
I claimed above that EP is a child of evolutionary biology. Part of the proof of that, is that EP grew so organically out of evolutionary biology. The study of animal behavior is called ethology. As post-war ethology gained in methodological sophistication, ethologists couldn’t help but notice that complex animal behaviors were clearly evolutionary adaptations. Ant species each reveal cognitively impressive social behaviors for an animal incapable of what we’d consider to be learning. In his book, Sociobiology, E.O. Wilson set out to explain how seemingly maladaptive behaviors like altruism could evolve. Wilson was a naturalist who (at the time) specialized in insects, yet his book covered many animals including humans. Academic heavyweights like Robert Trivers and Richard Dawkins also helped kick-start the sociobiology that would become modern EP- they were (or are) biologists, not psychologists.
It simply is not possible to study the behavior of animals (including humans) without concluding that many behaviors have been shaped by natural selection, just as physical traits have.
TL;DR
Evolutionary psychology can be understood as scientific inquiry predicated on just 3 uncontroversial premises:
1. The mind is what the brain does.
2. The brain is an organ, like other organs.
3. Organs are susceptible to natural selection.
That’s it. Everything else is just details.
