Evolutionary psychology is based on the idea that complex human behaviour can be explained by virtue of its adaptiveness. If a trait is maladaptive today, it will have been adaptive when the trait evolved, for example a sweet tooth leading to obesity these days would have been useful in the savannah where high-energy foods were scarce. This type of reasoning has attracted criticism of being just-so stories, due to the lack of available evidence, even if the logic seems plausible.
But what if we stuck to traits that have such a direct effect on survival and reproductive success that their adaptiveness couldn’t be disputed? Survival and reproductive success are the two strongest instincts, because these are the only two criteria natural selection acts on. Every other trait that is selected for is only chosen because of its effect on these two criteria. A trait can even benefit one at the expense of the other, which lead Darwin to differentiate between natural and sexual selection (e.g. the peacock’s tail – a ‘handicap’ display to advertise to the peahen its fitness, that it can survive despite having to grow it and carry it around).
These two strongest instincts we share with every other life form on earth, it’s just we’re (probably) the only ones who know it. You are the direct descendent of billions and billions of individuals, all of whom were better at surviving and reproducing than at least some others in their generation. Put like that, the evolution of complex life sounds at least intuitively more plausible.
So that’s two things we’re pretty good at, but is there anything else we’d like to do with ourselves now that we’ve evolved consciousness? The pursuit of happiness is one such goal, but research shows that, unsurprisingly, we need to pander to our instincts to be content. Comparing the income of a country with its happiness shows that initial gains in income lead to huge gains in happiness, but with diminishing returns after a basic subsistence level is reached. A similar pattern emerges if income is compared with life expectancy, so life expectancy would be a very good predictor of happiness – no surprise given the strength of the survival instinct.
Unfortunately as far as people in rich countries are concerned, economic wealth only improves wellbeing up to a point – which may represent a ceiling in human happiness. According to the authors of The Spirit Level, this is where absolute poverty stops being the limiting factor, and is replaced by relative poverty (economic inequality within a society). The evidence for a correlation between inequality and unhappiness is mixed, but the Nordic countries are among the happiest.
The evidence is much stronger for inequality diminishing societal wellbeing, and reducing mental illness, infant mortality etc. are laudable goals in themselves. The worse behavioural outcomes in more unequal countries are an evolutionary hangover, which can inform efforts to improve societies. People behave in ways that improve their place in the pecking order. All social primates are hierarchical to a greater or lesser extent, and position in the hierarchy is a strong predictor of survival and reproductive success. It is no longer as important for humans in rich countries, as resources are plentiful, so everyone can live and have children. In harsher environments like our evolutionary past, those lower in the hierarchy faced an earlier death and less chance of reproducing, so we have evolved a very strong instinct to climb the social ladder.
This instinct is mediated by the environment, however: it is less appropriate in an egalitarian context, where resources are shared out fairly. But it comes into its own in an unequal society, where being at the bottom of the pile could mean genetic oblivion. By this mechanism inequality leads to lower levels of trust, dealt with in an earlier post, and numerous other negative outcomes, which I’ll cover in future.