Why are we evil? This short piece  asks how the “Dark Tetrad” of behaviours could have evolved.

The Dark Tetrad is an extended version of the Dark Triad of three negative personality traits/behaviours (test yourself here  – I scored ‘infrequently vile’). The original three are ‘Machiavellianism’ – selfishly deceptive, manipulative behaviour; Psychopathy – indifference or failure to perceive the feelings of others; and Narcissism – vain self-obsession. Clearly there’s some overlap and it may not seem clear that these are anything but minor variants on selfishness, but research does suggest that they are distinct. Machiavellians, for example do not over-rate themselves and don’t need to be admired; narcissists aren’t necessarily liars or deceivers; psychopaths are manipulative but don’t really get people.

These three traits account for a good deal of bad behaviour, but it has been suggested that they don’t explain everything; we also need a fourth kind of behaviour, and the leading candidate is ‘Everyday Sadism‘ ; simple pleasure in the suffering of others, regardless of whether it brings any other advantage for oneself. Whether this is ultimately the correct analysis of ‘evil’ behaviour or not, all four types are readily observable in varying degrees. Socially they are all negative, so how could they have evolved?

There doesn’t seem to me to be much mystery about why ‘Machiavellian’ behaviour would evolve (I should acknowledge at this point that using Machiavelli as a synonym for manipulativeness actually understates the subtlety and complexity of his philosophy). Deceiving others in one’s own interests has obvious advantages which are only negated if one is caught. Most of us practice some mild cunning now and then, and the same sort of behaviour is observable in animals, notably our cousins the chimps.

Psychopathy is a little more surprising. Understanding other people, often referred to as ‘theory of mind’ is a key human achievement, though it seems to be shared by some other animals to a degree. However, psychopaths are not left puzzled by their fellow human beings; it’s more that they lack empathy and see others as simply machines whose buttons can freely be pushed. This can be a successful attitude and we are told that somewhat psychopathic traits are commonly found in the successful leaders of large organisations. That raises the question of why we aren’t all psychopaths; my guess is that psycopathic behaviour pays off best in a society where most people are normal; if the proportion grows above a certain small level, the damage done by competition between psychopaths starts to outweigh the benefits and the numbers adjust.

Narcissism is puzzling because narcissists are less self-sufficient than the rest of us and also have deluded ideas about what they can accomplish; neither of these are positive traits in evolutionary terms. One positive side is that narcissists expect a lot from themselves and in the right circumstances they will work hard and behave well in order to protect their own self-image. It may be that in the right context these tendencies win esteem and occasional conspicuous success, and that this offsets the disadvantages.

Finally, sadism. It’s hard to see what benefits accrue to anyone from simply causing pain, detached from any material advantage. Sadism clearly requires theory of mind – if you didn’t realise other people were suffering, there would be no point in hurting them. It’s difficult to know whether there are genuine animal examples. Cats seem to torture mice they have caught, letting them go and instantly catching them again, but to me the behaviour seems automatic or curious, not motivated by any idea that the mice experience pain. Similarly in other cases it generally seems possible to find an alternative motivation.

What evolutionary advantage could sadism confer? Perhaps it makes you more frightening to rivals – but it may also make and motivate enemies. I think in this case we must assume that rather than being a trait with some downsides but some compensating value it is a negative feature that just comes along unavoidably with a large free-running brain. The benefit of consciousness is that it takes us out of the matrix of instinctive and inherited patterns of behaviour and allows detached thought and completely novel responses. In a way Nature took a gamble with consciousness, like a good manager recognising that the good staff might do better if left without specific instructions. On the whole, the bet has paid off handsomely, but it means that the chance of strange and unfavourable behaviour in some cases or on some occasions just has to be accepted. I the case of everyday sadism, the sophisticated theory of mind which human beings have is put to distorted and unhelpful use.

Maybe then, sadism is the most uniquely human kind of evil?