The Theory of Primate Sentiments: Part Two

The story so far.

Robin Dunbar is arguing that language developed amongst apes as something that could replace grooming in facilitating larger social groups than could be supported by grooming. Adam Smith is lurking in the background with the promise made that there are errie similarities between Smith’s view of the world and Dunbar’s. My brother makes a cameo appearance.

Here’s a potted description of how Dunbar reckons we came down from the trees literally.

1 Monkeys became able to deal with the tannins in unripe fruit, making life tough for the ancestors of apes and humans. Apes cannot digest tannin.

2 As a result of this and perhaps climate change, apes experienced increasing pressure to find food beyond the forest floor and they began venturing into the open plain. (I think it might have been easier for evolution to just let apes develop the enzymes to digest tannin but I’m always thinking this about evolution. It seems to underdetermine every explanation. Dunbar didn’t answer this little puzzle and we proceed for want of an alternative, assuming that nature works in mysterious ways).

3 The plains were full of dangerous predators and one of the ways we survived was building larger social groups. The diagram at the head of this post illustrates Dunbar’s accompanying theory that group size gradually rose as humanity emerged from its knuckle dragging ancestry. Standing erect also helped people see predator threats and kept them cooler with more ventilation and less area for the sun’s rays to hit.

4 Brains take up a huge amount of energy ours takes up 20% of our energy compared with body weight of around 2% of body mass. Why did we suffer this drag? According to Dunbar it was the only way that larger social groups could be maintained. We sacrificed by making other organs more economical particularly our stomachs which, could contract given the increased meat in our diet. Meat takes less digestion to convert to energy than much vegetarian fare.

Theory of Mind

The most central thing in the development of the brain, increasing the size of the social unit and the co-evolution of language and brain size is the development of ‘a theory of mind’.

A ‘theory of mind’ can be explained in terms of the concept of ‘intensionality’. My own beliefs constitute first order intensionality. My beliefs about your beliefs constitute second order intensionality. And my beliefs about your beliefs about me (or something else) demonstrate third order intensionality. A knowledge that another’s beliefs may be false is either a kind of two and a half order intensionality or fully third order intensionality if the truth or falsity of a belief is a belief about what’s going on in another mind.

Now you need second and perhaps two and a half order intensionality for trickery to develop. And guess what? Monkeys but particularly the higher apes are the only animals where there is substantial evidence of tactical deception Dunbar’s book is full of them.

(Our family has a famous story of tactical deception. When my brother and I were young kids we went to Taronga Park Zoo and a very clever little monkey engaged my brother in the ritual of feeding him peanuts. He put out his left hand and David became so entranced by the idea of putting one or two peanuts into his inviting hand time that the monkey was, shortly afterwards able to use its other hand to snatch the whole bag from whence the peanuts were coming. David’s exposure at a young age to the injustice of second order intensionality became a sufficiently emotional experience to be remembered over four decades later. My father chuckled to himself for a large part of the rest of the day and indeed possibly the week.

Understanding that what’s going on in others’ minds might be at variance with the truth requires third order intensionality and this is only practiced rarely and imperfectly in the animal world.

Thus in one experiment food was put in only one of several opaque boxes. The subjects of the experiments (monkeys, apes and humans) had to choose an assistant to help them identify which box to open, and they had observed one of the assistants being present when the food was placed in the box whilst the other was not. Most, but not all of the chimps in this experiment worked out to ask the assistant who’d seen which box the food was put, whereas none of the monkeys did.

About another slightly more complex experiment Dunbar says this.

Although the chimps did better than the autistic adults at this task, they were nowhere near as good at it as five and six year old normal children (who have theory of mind). The chimpanzees certainly learned to solve the problem, but they weren’t as competent as one might have expected had they had full theory of mind. (p. 100)

And it is this third order intensionality that Dunbar identifies as uniquely human and co-evolving with language and with gossip as the social cement replacing grooming as the engine behind human evolution.

Theory of mind is, beyond question, our most important asset. It is a remarkable skill. Yet even ToM pales into insignificance by comparison with where this skill has taken us.

ToM has given us the crucial ability to step back from ourselves and look at the rest of the world with an element of disinterest. The starting point of all this was probably our ability to reflect back on the contents of our own minds. Why do I feel the way I do? Why am I angry now? . . . Understanding our own feelings is crucial to understanding those of other people. Without recognizing what we are seeing in others, we have no hope of delving into their minds sufficiently far to appreciate their mental reactions to the things they experience.

The real breakthrough is where fully developed third-order ToM allows us to imagine how someone who does not actually exist might respond to particular situations.

Dunbar develops this thought in the direction of culture and literature. I preume Smith wouldn’t disagree with this, but in his hand, what Dunbar calls “Theory of Mind’ becomes a theory of the ‘natural’ ethical relations within human society based on their ‘moral sentiments’.

Not only does Smith have people’s individuality grow within a social setting. It is sympathy precisely the realisation of third order intensionality (that others look upon us as we do upon them) that is the engine of human society and indeed of the evolution of human consciousness.

Thus for instance Smith writes

We can never survey our own sentiments and motives, we can never form any judgement concerning them; unless we remove ourselves, as it were, from our own natural station, and endeavour to view them as at a certain distance from us. But we can do this in no other way than by endeavouring to view them with the eyes of other people, or as other people are likely to view them. Whatever judgement we can form concerning them, accordingly, must always bear some secret reference, either to what are, or to what, upon a certain condition, would be, or to what, we imagine, ought to be the judgement of others.

In the next exciting instalment – a postscript really – we learn about Adam Smith’s own theory of the evolution of language and how his general approach to the evolution of language has deep similarities with his explanation of the evolution of markets and of morals.