As you are probably aware, it is possible to teach chimpanzees basic sign language. Perhaps what hasn’t hit home though is how amazing that is considering the importance and implications language acquisition. You see, many psychologists believe that without a form of language, it is impossible for us to perform many of the higher-level brain functions that we associate with being human. It is our understanding and use of language that allows us to work as a society and to communicate effectively, but it is also what we use to reflect on ourselves and on our surroundings. Without language, how would you plan in your head what you were going to have for dinner tonight? Or think up stories? Or solve maths problems?
Supporting this view is the fact that deaf people who never learn sign language suffer major cognitive difficulties as a result and have highly stunted IQs. We need to learn a language and internalise it in order to be self-aware and to manipulate ideas in our minds.
So if a chimpanzee can use sign language, does that mean that these skills are not uniquely human? Does that mean that you can give a chimpanzee the ability to plan and to reflect on their own behaviour? Does that mean that if you taught several chimpanzees how to sign, they could communicate with one another and start developing a society, telling stories, and creating useful tools and rules?
The Importance of Theory of Mind
Well actually the answer to that question is probably ‘no’. Why? Because although the chimpanzees are able to communicate, they lack a theory of mind which in turn limits the usefulness of that communication.
So what is a theory of mind? Essentially this is our ability to attribute goals, experiences and ideas to other people. In other words, it is our ability to look at someone and know that they’re sad, or to see them looking through the fridge and infer that they must be hungry. Based on our own experiences and behaviours we can deduce what others must be thinking and then modify our own behaviour accordingly. Which is of course rather crucial for true communication.
Who Has a Theory of Mind?
A theory of mind is not something we are born with however and studies suggest that we don’t develop one until the age of about four years old. This has been established using experiments such as the well-known ‘Sally Anne Test’. This test was devised by Simon Baron Cohen (who happens to be the brother of Sacha Baron), and works by getting a child to listen to a short story then predict the ending. In the story Sally has a biscuit and puts it in her basket before leaving the room. Anne, who was also in the room, then moves the biscuit into a box before Sally comes back without her seeing. The question then posited is: ‘does Anne look for the biscuit in the basket or the box first?’.
Of course the answer should be basket, as Sally has no reason to suspect foul play. However children under the age of four will nevertheless insist that Sally will look in the box first – because that’s where the biscuit is after all.
This test can also be used to identify autism in its early stages. While most children will be able to pass the Sally Anne Test by the age of four, children with autism will take significantly longer and may be unable to pass it at all.
A theory of mind when combined with language then is what gives us the full range of abilities that are normally possessed by adults, and when this is impaired we see the impact manifest in autistic patients.
Do Animals Have a Theory of Mind?
So what leads researchers believe that these chimpanzees lack a theory of mind? Well although those chimpanzees are able to sign, able to ask for food and answer questions and puzzles, they all fall short in one area: none has thus far asked a question.
And the reason for this, researchers believe, is that they don’t recognise that humans might have useful information. All animals display curiosity (cats most famously…) so it’s not that, and one remaining explanation is that it might be due to a lack of theory of mind.
However this is still only a theory, and a contentious one at that. Some researchers are certain that animals do have a theory of mind, and one chimpanzee in particular named ‘Kanzi’ has reportedly demonstrated this on numerous occasions. Even dog owners might suspect that their pets have something akin to a theory of mind – who’s ever been chased around a table by their dog only for them to then switch directions and catch you out? Or had your dog do something naughty as soon as you turn your back?
It may be that a theory of mind is much more of a spectrum rather than a binary. Perhaps different animals and even different people have a theory of mind to differing extents? Perhaps it’s only once that theory is developed enough for us to start asking questions though, that we begin to learn and develop at an increased pace.