We last shared a common ancestor with the other great apes around 6 or 7 million years ago. Yet our brains were, essentially, ape-sized until around 2 million years ago, and did not reach contemporary proportions until sometime within the past 200,000 years. Material evidence suggests that humans used ochre to make drawings on rocks only within the past 75,000 years; and representational objects began to appear in the archaeological record about 40,000 years ago. Unfortunately, speech and gesture do not fossilise, but if we consider that no ape can speak (beyond a tiny handful of laboriously produced utterances) and if we assume that language requires a brain larger than an ape’s, we can define a window of time between, roughly, 2 million years ago and 40,000 years ago in which spoken language emerged. Based on a range of data from archaeological to neurophysiological, the computational neuroscientist Michael Arbib estimates this window at around 1.5 million to 100,000 years ago. Somewhere in this time span, we became qualitatively distinct from all other animals by any reasonable measure. [...]
One day, I came back to Clint’s cage and saw him point with his index finger at a grape that had fallen on the floor, due to a technical problem with the automated reward-delivery system. The grape was out of his reach, and he pointed to it, making loud raspberry sounds (like a Bronx cheer), looking back-and-forth between me and the fruit. Now, you don’t need a PhD in experimental psychology to be able to interpret this signalling behaviour, right? However, without significant indoctrination into late 20th-century intellectual fashions you might not realise that Clint’s pointing was, at the time, theoretically impossible. Almost everybody knew, at that time, that human pointing – this ability to capture and redirect the attention of another being to a specific entity – was part of our unique adaptation for language. In language, we refer to things with words. We say, for example: ‘Look at the dog!’ or ‘I think that blue car is following us.’ Symbolic reference seems easy enough as we speak in daily interactions, but hop on a plane and travel somewhere where people don’t speak your language, and the same words just don’t work for us the way they do back home. This is because languages are, for the most part, mutually unintelligible. The whole system breaks down if we don’t have a shared symbolic code. But pointing will often work to establish joint reference.
This highlights different kinds of reference. In speech, there is a mostly arbitrary relationship between a symbol and the thing it refers to. The word ‘big’ is not bigger than the word ‘little’, for example. The word ‘dog’ does not sound like a dog, and so on. In contrast, the relationship between a pointing gesture and its referent is not arbitrary – the pointing hand acts like a geometric ray, so that while a point might not usually resemble the referent, it nevertheless has a spatial relationship with it. Pointing is an interactive skill in human infancy. Children begin to follow pointing gestures to targets in their fields of view by about nine months of age; by approximately 12 months of age, they can follow points to more distant objects or locales. Children also begin to produce pointing gestures for others, at roughly the same age that they begin to speak, around the end of their first year of life. [...]
What this means for understanding the evolution of language is that our ancestors didn’t have to evolve a specialised manual gesture to foster language acquisition in that window of time when language or protolanguage originally appeared, 1.5 million to 100,000 years ago. Our ancestors who invented language were already pre-adapted for pointing, and as our infants became ever more helpless for ever longer periods of early development, pointing became an increasingly useful tool for social manipulation in our species.
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