Scientists are prone to going on and on about how strikingly early in life we are able to comprehend speech. Our children’s aptitude for reading, however, doesn’t cause much excitement. At first glance this seems sensible: children comprehend speech fairly well by two, whereas they typically can’t read until about five. This is because, the standard story goes, we evolved to comprehend speech but did not evolve to read. And while one might debate whether we have evolved to comprehend speech, no one believes we evolved to read. Writing is only several thousand years old, far too short a time to have crafted reading mechanisms in our brain. And for many of us, our ancestors only started reading one or several generations back.
But are children really so clunky at learning to read? At five years old, most children can’t be trusted to pour a pint of beer without spilling it, and most can’t even do stereotypical ape behaviors like somersaults and the monkey bars. And yet these same wee ones are reading. That’s quite an accomplishment for an ape, especially one who gets read to so infrequently compared to getting talked to.
Children are, in fact, quick learners of reading, and our brains become fantastically capable readers. How can we come to be so good at reading if we don’t have a brain for it? Is it because our visual system can handle any writing one may throw at it? No. Our children would be hopeless if writing looked like bar codes or fractal patterns. How, then, did apes like us come to read?
Gifted neuroscientist Stanislas Dehaene argues in his new book, Reading in the Brain (Viking), that we read not because we have a reading instinct, and also not because our visual brain is a particularly pliable learner. Rather, we read because culture “neuronally recycles” our visual system. Culture over time has seen to it that the letter shapes of our writing systems have the shapes our visual system is good at processing. In particular, the brain is competent at processing the contour combinations that occur in natural scenes, and writing systems have come to disproportionately use these shapes.
For example, below are four configurations each having three contours and two Ts. Three of the four can happen in natural scenes, but one of these cannot, and it turns out that only this oddball is rare across human writing systems. It is not so much that the brain has a reading instinct, but that writing has a brain instinct. In fact, to the extent that writing has come to be shaped like nature (in order to get into the brain), writing has a nature instinct.
More generally, Dehaene’s line of thinking suggests that much of what makes humans stand so far apart from the other apes is a result of neuronal recyclling – not a result of natural selection at all.
This first appeared on January 12, 2010, as a feature at the Telegraph.