I spent a fair amount of time hanging out with professional poker players while writing How We Decide. For the most part, these players have exquisite control over their facial expressions, so that those micro-muscles around the eyes and mouth rarely betrayed their inner thoughts. (The players reacted with the same look of unflappable boredom to a pair of aces and a hand with mismatched number cards.) But I was always amused by their insistence on wearing opaque sunglasses inside the dimly lit casino. What relevant information did they think their eyeballs would betray? (Most muttered something about dilating pupils.) It turns out, though, that the players were right to shield their eyes, as a new Current Biology paper proves:
Here, we demonstrate how the eyes and their position give an insight into the nature of the systematic choices made by the brain’s ‘random number generator’. By measuring a person’s vertical and horizontal eye position, we were able to predict with reliable confidence the size of the next number — before it was spoken. Specifically, a leftward and downward change in eye position announced that the next number would be smaller than the last. Correspondingly, if the eyes changed position to the right and upward, it forecast that the next number would be larger. Apart from supporting the old wisdom that it is often the eyes that betray the mind, the findings highlight the intricate links between supposedly abstract thought processes, the body’s actions and the world around us.
The larger lesson is that the brain can’t escape its embodiment. Even abstract information – and what’s more abstract than a random number? – is subject to the heuristics of physical movement: Up means higher, down means lower. Because the mundane world of Newtonian physics is built into the mind at such a basic level, we are forced to re-use these same mental shortcuts when thinking about math, or playing poker. I think experiments like this also explain why it’s so much harder to understand quantum mechanics, or string theory. (I’m referring to an intuitive, visceral kind of understanding. As Niels Bohr once said, “Anyone who is not shocked by quantum theory has not understood it.”) We simply weren’t built to think about wave-particle duality, or the possibility of 11 hidden dimensions. It makes no sense to us. Our eyes don’t know how to move.
PS. For another cool study of embodied cognition, check out this post on Neurophilosophy.