‘If language began with gestures around a campfire and secret signals on hunts, why did speech come to dominate communication?…’
— via Aeon
Cognitive scientist Kensy Cooperrider notes the difficulty of explaining the origin of language. One particularly resilient notion has been that it began as gesture, which seems intuitive and is also borne out by examination of the communication proclivities of our primate relatives. Now to the core problem: people gesture but, outside deaf communities, speech predominates. Some factors include that speech is abstract; that it is better in the dark; that it frees up the hands to do something else; and, perhaps most important, that it takes less caloric expenditure than signing.
So if there are good reasons to transition from gestural to verbal communication, how did it happen? There is longstanding and growing evidence of the close neurobiological coupling of hand and mouth. The mouth for example, is very active in signing, often echoing in miniaturized form. This provides a notion of a gradual route to adopt a more ‘compact’ form of communicative behavior, with gesture remaining vestigial.
As challenging as this question is, Cooperrider ends up observing, it is only one piece of an enormously mysterious puzzle:
Even if we were able to establish some version of a gesture-first proposal as not merely plausible but likely, there would be many more layers to contend with. We would also want to understand how we came by our abilities to read other minds, to sequence and combine ideas, to conceptualise abstractions such as ‘tomorrow’ and ‘truth’. We would need to explain, not merely whether we first conveyed meaning by hand or by mouth, but why we felt an itch to mean anything at all.