Do apes really have “a theory of mind”? This research, reported in the Guardian, suggests that they do. We don’t mean, of course, that chimps are actually drafting papers or holding seminars, merely that they understand that others can have beliefs which may differ from their own and which may be true or false. In the experiment the chimps see a man in a gorilla suit switch hiding places; but when his pursuer appears, they look at the original hiding place. This is, hypothetically, because they know that the pursuer didn’t see the switch, so presumably he still believes his target is in the original hiding place, and that’s where we should expect him to go.
I must admit I thought similar tell-tale behaviour had already been observed in wild chimps, but a quick search doesn’t turn anything up, and it’s claimed that the research establishes new conclusions. Unfortunately I think there are several other quite plausible ways to interpret the chimps’ behaviour that don’t require a theory of mind.
- The chimps momentarily forgot about the switch, or needed to ‘check’ (older readers, like me, may find this easy to identify with).
- The chimps were mentally reviewing ‘the story so far’, and so looked at the old hiding place.
- Minute clues in the experimenters’ behaviour told the chimps what to expect. The famous story of Clever Hans shows that animals can pick up very subtle signals humans are not even aware of giving.
This illustrates the perennial difficulty of investigating the mental states of creatures that cannot report them in language. Another common test of animal awareness involves putting a spot on the subject’s forehead and then showing them a mirror; if they touch the spot it is supposed to demonstrate that they recognise the reflection as themselves and therefore that they have a sense of their own selfhood. But it doesn’t really prove that they know the reflection is their own, only that the sight of someone with a spot causes them to check their own forehead. A control where they are shown another real subject with a spot might point to other interpretations, but I’ve never heard of it being done. It is also rather difficult to say exactly what belief is being attributed to the subjects. They surely don’t simply believe that the reflection is them: they’re still themselves. Are we saying they understand the concepts of images and reflections? It’s hard to say.
The suggestion of adding a control to this experiment raises the wider question of whether this sort of experiment can be generally tightened up by more ingenious set-ups? Who knows what ingenuity might accomplish, but it does seem to me that there is an insoluble methodological issue. How can we ever prove that particular patterns of behaviour relate to beliefs about the state of mind of others and not to similar beliefs in the subject’s own minds?
It could be that the problem really lies further back: that the questions themselves make no sense. Is it perhaps already fatally anthropomorphic to ask whether other animals have “a theory of mind” or “a conception of their own personhood”; perhaps these are already incorrigibly linguistic ideas that just don’t apply to creatures with no language. If so, we may need to unpick our thinking a bit and identify more purely behavioural ways of thinking, ones that are more informative and appropriate?