There is one feature of social learning that we have not yet considered, and this is teaching. We might see teaching (as opposed to imitation by copying) as guided learning. In humans, the teacher monitors the actions of the pupil and corrects or guides the pupil when a mistake is made. This is a very special process that is clearly characteristic of much of what we as humans do. Teaching allows us to learn rapidly - and with the fewest possible mistakes - many of those features of human culture that define us and our societies. However, we should be cautious about placing too much emphasis on teaching as a learning process when trying to understand the differences between us and our nearest relatives. After all, teaching is a process for speeding up the learning process; it is not the learning process itself. The pupil essentially still learns by imitation, copying or trial and error. Nonetheless, we can legitimately ask whether teaching is common among our primate relatives or unique to us.
The short answer to this question seems to be that, by comparison with what we see in humans, teaching is extremely rare in the animal kingdom. To be sure there are documented examples of what looks very much like teaching. Cat mothers often bring half‑alive mice or birds for their kittens to practise killing. Chimpanzee mothers leave intact nuts for their offspring to crack. However, we perhaps need to recognise here that there is a crucial distinction between facilitating (providing an opportunity for trial-and-error learning to occur) and teaching (deliberately showing how something should be done). Christophe Boesch, who has studied the Tai chimpanzees for two decades or more, was able to docoment many cases of the former, but only two apparent instances of the latter (and many would regard even these as somewhat charitable interpretations). In one case, a mother slowed down and modified her nut cracking so her offspring could follow it more easily; in the other, a mother altered the position of her son's nut when he was having trouble hitting it. But, it takes on average about ten years for a chimpanzee to learn how to crack nuts efficiently. In contrast, it takes only a few weeks of intensive training for a child to learn how to tie its shoe laces, a behaviour that is considerably more complex. As with the blue tits and the Japanesemacaques, this rather suggests that learning how to crack pahn nuts is really based on simple stimulus enhancement or emulation, combined with trial-and-error learning, not on imitation or teaching.
In humans, the key to teaching, as Mike Tomasello has pointed out, is intention: the teacher deliberately intends to modify the actions of the pupil. Does either of the Tai chimpanzee examples meet this criterion? The answer is: (probably) yes. But even so, the fact that we can find only two dear examples of teaching in literally thousands of chimpanzee-years of observation by scientists in different parts of Africa speaks volumes. Clearly, the capacity exists at least in minimal form, but it is not used as often as we might expect were we studying humans. In humans, teaching goes on endlessly, day in day out.
And here, perhaps, is the unexpected lesson of the comparative work on cognitive development in humans and apes. Human babies are imitation machines who seem to suck up anything and everything they come across that involves imitation of another individual's behaviour. Teaching helps to guide that up-take, but without the human child's seemingly infinite capacity for imitation, it is doubtful whether any amonnt of teaching by the parent would help in the absorption of so much behaviour in so short a space of time. In contrast, young chimpanzees seem more proactive and clued in to finding things out for themselves. This contrast is a bit of a puzzle really, because, when you think about it, blind copying would seem to be a remarkably dull-witted intellectual capacity. It is hardly rocket-science. Why should the yonng of the most cognitively advanced species on earth seem to be less clned into the world in which it lives than the young of other intellectually less well endowed apes?
A Very Cultured Ape
Impressive as these examples of chimpanzee culture are - and I really have no problem about using the term 'culture' when talking about them - they remain, in the final analysis, unsatisfying. For one thing, it is the relative scarcity of genninely cultural behaviour that is troubling. A grand total of 39 elements of cultural behaviour from the hundreds of thousands of hours of chimpanzee-observation in the wild and in captivity is not an impressive tally. Were we to conduct the same experiment on humans, we would surely find so many examples of differences that the chimpanzee catalogue would fade into insignificance, even if it was ten times as large as it currently is. But, there is another and more troubling absence in the great ape story: we still see nothing that smacks of those activities that form so fundamental a part of human culture - story-telling and music, and beyond them that whole panoply of religion and ritual, and the significance of a spirit world that sits apart from the real world in which we all live.
The more I think about it, the more obvious it becomes that there is one fundamental reason why chimpanzees will never write the tales of Shakespeare or compose the poems of Baudelaire or T. S. Eliot. The simple fact is that they do not have the levels of intentionality to be able to do it. Even if great apes could aspire to theory of mind (second-order intentionality) that would not grant them the capacity to prodoce these most human of all cultural phenomena.
In short, while language itself is not essential to literature, advanced theory of mind is. Language is, of course, essential for transmitting the story from one individual (the composer) to another (the listener), otherwise we would never get to hear about it. But language is not essential for constructing the story in our minds. We can each compose a grand Shakespearian tragedy in our heads, and go on to enjoy the artistic devices and cleverly constructed plots without ever having to speak a word. We do not even have to do it in words. I could compose all the stories in the universe in what is sometimes referred to as the 'language of thought' (the silent thoughts that go on inside our heads in a kind of wordless, perhaps even visnal, stream). It would be tough on the rest of you to have missed out on all my works of undoubted genius...but that, as they say, is not my problem. It would be much like Samuel Pepys writing his diaries in his own secret code for his own enjoyment when he read them again later.
Nonetheless, there is something unsatisfactory about suggesting that my silent literary endeavours constitute high culture. Without a community of story-tellers and their audience, it is questionable as to whether we would really have Culture with a capital 'C'. The cultural community that make sense of the stories I tell interpret them in terms of their own individual experiences of life, applaud the good ones and scoff at the bad, adding their own nuances of interpretation as they do so. This, surely, is what human culture is all about. Story-telling becomes culture because the stories we tell come to influence the minds of others. Strictly speaking, we do not need language for that, but we do need some form of communication. Mime might sufffice, Egyptian hieroglyphs would do admirably. Language does happen to work particularly well, however.
If literature remains a purely human domain because of our advanced mind-reading abilities, then does it provide us with any purchase on the question of when this key defining feature of humanity evolved? The short answer is no. Because stories do not fossilise. But there is one form of story-telling that does leave its imprint in the archaeological record - religion. Religion requires us to be able to conceive of imaginary worlds, worlds that we do not directly experience. We have to be able to step back from the immediacy of our everyday experiences and ask: 'Could the world be otherwise than as I experience it? Could there be a parallel world inhabited by beings that I cannot see and touch directly in the way I see and touch objects and individuals in the world we all inhabit?'We have to be able to imagine that the world is other than it seems to be from our everyday physical experiences of it, and to be able to suppose that this parallel universe out there somewhere, peopled as we imagine with other beings, can influence our world - and perhaps, in their turn, be influenced by us.
Herein, then, lies the great divide between ourselves and our ape cousins: the world of the imagination. We can imagine that something can be other than it is. We can pretend that there are fairies at the bottom of the garden. We can construct rituals and beliefs that have no intrinsic reality other than in our heads. Other animals cannot do that because they cannot step back from the world and wonder how it might be if it was different from the way they perceive it to be. And so we are brought full force to the one thing we have skirted carefully around, the issue of religious belief.