What are the ultimate reasons for behaviour? This blog is a platform for my speculative musings on the subject. Most topics will fall under evolutionary psychology, which seeks to explain behaviour as genetic adaptations. But maybe the less well-known field of human behavioural ecology is more apt, as it emphasizes the evolution of behavioural flexibility in response to environmental variation. This goes beyond a simple nature/nurture dichotomy: your genes interact with the environment to produce behaviour apt to the environment. A few traits are completely genetically determined, such as the basic facial expressions you make, and some others are completely environmentally determined, such as which language you speak. All other traits are determined by some combination of genes and environment, and are of most interest here.
The staples of evolutionary psychology tend to be behaviours at the genetic end of the spectrum, including human universals. Human behavioural ecology, on the other hand, concerns the evolution of a repertoire of potential behaviours, only some of which are activated. We undergo ‘calibration’ to our environment, to ensure the appropriate response to it, and this is why pregnancy, infancy and childhood are so important in influencing later life. This calibration is why I think that explaining variation in behaviour is potentially more practically useful than explaining why some behaviours are universal. Variation in behaviour allows for cultural variation to be tested as a potential cause.
For instance, mental illness may be cross-culturally universal, and this may be partly because some genetic mutations increase the carrier’s chance of being mentally ill. Prevention or treatment in the form of screening or gene therapy are a long way off though. However, while mental illness may be universal, it varies widely between countries, with rates ranging between less than 10% to over 25% even within rich countries. If variables can be identified that correlate with these rates, they might be an important determinant, and may be amenable to manipulation through government policy. I firmly believe in this process of evidence-based policy, whatever field of science the evidence comes from, and I will be looking into it in future posts.