There are chicken and egg problems. And there are tail and dog problems. The thing is, I’m not sure which of these problems I’m facing at the moment in regards to defining moral ecology.
I recently had a very fruitful, if highly critical, experience at the Philosophy of Biology at Dolphin Beach workshop. Amidst the splendour of the New South Wales south coast, and between midnight bonfires on the beach, I gave a paper on evolution and moral ecology.
The thesis was this:
The highly variegated hominin social environment of the last few million years shaped our psychology to produce a polymorphism of psychological traits that promote a range of behavioural strategies when it comes to social living.
For example, the inherent difficulties in identifying trustworthy partners for potentially risky cooperative ventures has made some people naturally more predisposed towards being trusting and others towards being suspicious.
Another example might be that some people are predisposed to be quick to anger, particularly in the face of perceived disloyalty or defection in cooperative ventures, and others are predisposed towards being more forgiving.
These predispositions promote behaviours that follow fairly predictable patterns – more trusting people engage in more cooperative ventures but expose themselves to greater risk of defection; more forgiving people maintain more social bonds by punishing less but make norm enforcement more difficult.
And these patterns match what we’d expect to see when we do a strategic analysis of social behaviour, such as game theoretic analyses. These show that many social problems – such as how much one ought to trust others, or how much one ought to punish transgressors – have no single optimal answer. As such, often a pluralism of strategies within a population will most stably produce high levels of cooperation rather than the entire population pursuing the same strategy.
So, that’s my thesis: that the nature of social life placed selective pressures on our psychology producing and maintaining these polymorphisms – perhaps manifest in variation in emotional responses or variation in personality traits – that produce a pluralism of social behavioural strategies.
The Chicken and the Dog
As I was informed by many of the PBDB attendees, life is rife with variation. Variation is the norm, and is not necessarily the product of natural selection but is a cause of natural selection. Mutation and recombination produce new phenotypes, and it’s this variation upon which natural selection acts, tending towards phenotypic stability when an adaptive trait is found. As such, uniformity, not variation, is the interesting exception that demands an evolutionary story to be told.
If a species has noses that vary in size and shape, that (alone) doesn’t hint at any adaptive explanation for the variation. However, if the species have noses that are all strikingly familiar, then that’s something worth investigating.
Furthermore, adaptive polymorphisms in behaviour aren’t unique to hominins. Fish, birds and especially higher primates often exhibit quite visible phenotypic (and likely genetic) polymorphisms when it comes to things like risk taking or what we might call introversion/extraversion. So the psychological variation in humans, where it exists, might have arisen long before we split from the other great apes to form the hominin line.
Hmm. So it’s looking more like a tail/dog problem for me. I was suggesting the tail (the selective social environment) produced the dog (the psychological variation). Perhaps the right answer is that the dog (psychological variation) has produced the tail (the heterogeneous social environment and varied behaviour).
If that’s the case, then a chunk (not a pivotal chunk, but a sizeable chunk none the less) has been carved from my thesis.
The Egg and the Tail
However… while I take the above points very seriously, I don’t think they represent a knockdown rejection of my adaptive story of human psychological variation and the impact it has on social/moral behaviour.
Firstly, variation might well be the norm, but when that variation follows particular patterns, it’s no longer easily dismissed as a product of mutation, recombination and drift etc. In fact, if a trait varies predictably along particular dimensions and in particular proportions within the population – say half the noses are short and snub, and the other half are long and pointy – that trait is not variable in at least one important sense. Certainly, the morphology might be variable, but the pattern of variation is relatively uniform – and that uniformity is something worth looking in to.
And I think there’s ample evidence to suggest there are predictable patterns in psychological variation. Personality types vary along predictable dimensions (as mapped by the Big Five – Openness, Conscientiousness, Extraversion, Agreeableness, Neuroticism – for example) or integrative complexity.
Granted, I’m leaning on emotional variation to explain things like dispositions to trust or punish, and emotional variation is harder to slot into the more complex channels found in personality. Anger might just vary due to non-adaptive reasons, for example. However, it seems striking that variation in anger responses might produce behaviours that correspond closely to the expected behavioural patterns we see from game theoretic analyses. But that might be my bias showing.
As for the notion that such adaptive polymorphisms that do exist emerged prior to the evolution of hominins, thus predating the complex and heterogeneous social environment that I’m suggesting produced the adaptive psychological polymorphisms… I don’t think that deals a crippling blow to my theory.
It might be that the salient adaptive landscapes that produced these polymorphisms – such as the trade-off between risky and cautious behaviour – prepped us for dealing with similar trade-offs in the hominin social environment, with the latter then maintaining the polymorphism.
If that’s the case, it weakens my argument – it makes some psychological variation an exaptation rather than adaptation – but that doesn’t mean the variation isn’t still interesting.
I still have some work to do in order digest the feedback to my talk, and I may yet have to make some revisions to my thesis – or even drastically cut the amount of talk I have about adaptive human variation due to the Pleistocene social environment. However, my core thesis of the importance of understanding ‘moral ecology’ stands.
Moral ecology is the independent notion that many of the problems of social living have no single solution that produces optimal levels of prosocial and cooperative behaviour. As such, a pluralism of behavioural strategies can often produce the most stable and cooperative social groups.
We appear to have psychological variation that promotes such a pluralism of strategies, and this may be a coincidence, or purely a result of environmental variation and cognitive plasticity. But it’s still possible that there is an evolutionary story to tell. And I’m still going to have a crack at telling it.