author : Reginald B. Adams, Jr.

This started life as Hurley’s dissertation, but fear not: it is not some dull stodgy academic treatise. Despite being peppered with jokes, however, it is also not a side-splitting read. It is instead a clearly written in-depth account of the authors’ evolutionary cognitive theory of humour. The overarching argument is excellently summarised in the back-cover blurb (above); in a little more detail, it runs:

• All our behaviour, including thinking, is guided by emotions: without some emotional prod we would never make any actual decisions.
• Our emotions have evolved to produce rational behaviours (most of the time).
• Our thinking and decision-making usually needs to be done in real time: we need to react to the tiger now, not once we’ve finished evaluating all the possibilities.
• If we reason speedily with limited and uncertain information, we will make mistakes.
• These mistakes need to be fixed, to stop our mental space becoming clogged up with incorrect inferences.
• Correcting mistakes is hard work, so we have evolved an emotional "reward": mirth, which we experience when we consciously recognise an unconsciously committed incorrect belief (modulo some further conditions).
• This emotion, like others, can be exploited to new ends: here, humour and comedy.

This thesis is introduced in the context of an emotional and cognitive model of how we think. Emotion is clearly important in things like “fight or flight”, but also for many other aspects of our life. Certain forms of brain damage that inhibit emotions make it difficult or impossible for those people to make decisions: not because they can no longer reason, but because they have no urge to make a decision. Thinking itself is such hard work, we need emotions to encourage us to do so.

Although we think incessantly, at times we need to think quickly, and to make a decision before we have all the information. There is an evolutionary advantage to literally jumping to conclusions: those that pondered more deeply were eaten. But if we don’t have all the information, inevitably we will make mistakes, no matter how well evolution has honed our conclusion-jumping heuristics into rational emotional behaviours.

Mistakes can be dangerous, as they will include false information about the world, which later will pollute the very reasoning we need in order to survive. So we have evolved mechanisms to help us correct these mistakes.

However, this error correction is expensive, and is competing for the same resources that the original thought uses. Something expensive needs some reason to happen. This is the key to the authors’ model: the reason is the evolved reward mechanism of mirth. Sweet foods are not intrinsically “sweet”; we experience them as sweet (a pleasant emotional response) because we are evolved to find them so: sugar was a rare and valuable energy source. Similarly, jokes are not intrinsically “funny”; we experience them as funny (a pleasant emotional response) because we are evolved to find them so: error correction is a valuable cognitive function.

Having introduced their thesis, the authors then subject it to various challenges. It needs to account for the diverse range of things we find funny, and yet should also explain why closely related things are not funny. They do this in considerable detail, picking apart and analysing a wide range of humorous and related event. Of course, picking apart a joke destroys its humour; interestingly, the theory even explains why it destroys the humour.

This is a fascinating and well-argued account of a particular aspect of our evolutionary heritage. Recommended. (Some of the example jokes included are even funny.)