Humans have a very strong need to communicate. This ‘drive to share thoughts’ has been pointed out as one of the main differences between us and other species. It is, I suppose, what makes me write the present post to you, reader.
Another exclusive characteristic of human communication is our cooperative willingness to infer the meaning of signals. Other animals ‘share thoughts’ directly, for example, when warning each other about the presence of predators. Our communication, however, involves an awareness that I have an intention to tell you something with this text; it requires an engagement based on your recognition of my intention.
This psychological way of picturing human communication or language, however, cannot tell us much about what it is or how it evolved. First, sharing thoughts cannot be an end in itself. Thoughts must have an effect on your behaviour as a receiver, one that is beneficial to both you and me. For example, chimpanzees benefit from warning others about poisonous snakes insofar as the group is important for their survival and reproduction, or because there are relatives in the group. Therefore, to be consistent with biology, our drive to share thoughts should be translated as a drive to make others respond.
This behavioural aspect is plain to see in human society. For instance, many will warn you these days about pathogenic viruses, a kind of poisonous snake that is always hiding. However, there is a difference between these two alarm calls: When a chimpanzee warns the group about a snake, it does not intend that others respond to the call; it intends that others react to the snake. In contrast, humans intend to make others respond to symbolic calls such as ‘SARS-CoV-2’, ‘God’ or the ‘Devil’ regardless of their truth-value. When we threaten others with burning in hell or with discrimination for not acting as we want them to, our focus is on responses to signals, rather than on reactions to dangers.
Similarly, the intention that underlies a parent’s linguistic behaviour (see my previous post) is that the child responds to signals. Non-meaningful events, such as when a waitress casually drops food on the table, become meaningful signals, ‘gestures’, because the parent intends to make the child respond to them.
Pictured like this, it is easy to see why human communication would involve an expression and recognition of intentions, and why these psychological traits would have evolved: There are consequences for not responding. The parent’s intention is not so much to share thoughts with the child, but to punish him if he does not respond appropriately.
Indeed, from a biological perspective, demanding attention from receivers seems like an odd signalling trait, as if this information we are eager to share were not necessarily valuable. Nonhuman animals produce signals because there already is an engagement on the part of receivers, who are willing to respond in ways that are beneficial to them, such as by avoiding a snake. Moreover, nonhuman signallers already have an intention to ‘make these receivers respond’, insofar as their behaviour as organisms is intentional, purposeful, unlike the behaviour of inanimate matter.
Picture, for instance, how a songbird tries to ‘make a female respond’. The bird can be said to have a ‘drive to share thoughts’ regarding his fitness as a mate. However, only human beings actually behave in ways that reveal an intention to make receivers respond.