The narrow fellow in the grass: human infants associate snakes and fear.

Why are snakes such a common target of fear? One current view is that snake fear is one of several innate fears that emerge spontaneously. Another is that humans have an evolved predisposition to learn to fear snakes. In the first study reported here, 9- to 10-month-old infants showed no differential spontaneous reaction to films of snakes versus other animals. In the second study, 7- to 18-month-old infants associated snakes with fear: As predicted, they looked longer at films of snakes while listening to a frightened human voice than while listening to a happy voice. In the third study, infants did not look differentially to still photos of snakes and other animals, indicating that movement is crucial to infants' association of snakes with fear. These results offer support for the view that humans have a natural tendency to selectively associate snakes with fear.