To uncover this ability, Pessiglione and colleague Chris Frith, of University College London, tested 20 volunteers with a simple game based on winning and losing small amounts of money.

On a computer screen, the volunteers watched an animated abstract pattern which for a couple of tenths of a second included one of three symbols part way through. Unbeknownst to the subjects, the symbols indicated whether they would lose or gain £1 or break even if they accepted the gamble.

Surprisingly, subjects got better at predicting whether they would win or not, eventually plateauing at slightly above chance, strong evidence that volunteers do not consciously notice the symbols but are affected by them nonetheless.