Do 5-Month-Old Infants Possess an Evolved Detection Mechanism for Snakes, Sharks, and Rodents?

The four experiments reported here used the preferential looking and habituation paradigms to examine whether 5-month-olds possess a perceptual template for snakes, sharks, and rodents. It was predicted that if infants possess such a template then they would attend preferentially to schematic images of these non-human animal stimuli relative to scrambled versions of the same stimuli. The results reveal that infants look longer at a schematic snake than at two scrambled versions of that image and generalize from real snakes to the schematic image. The experiments also demonstrate that 5-month-olds show no preferential looking for schematic sharks or schematic rodents relative to scrambled versions of those images. These data add to the growing support for the view that humans, like many non-human animals, possess an evolved fear mechanism for detecting threats that were recurrent across evolutionary time.