Who is doing what to whom? Young infants' developing sense of social causality in animated displays.

In two different experiments a visual habituation/dishabituation procedure was used to test groups of 3-10-month-old infants for their ability to discriminate the role reversal of two abstract figures (discs of different colors) chasing each other on a computer screen. Results of the first experiment point to a reliable age effect. Only 8-10-month-old infants tended to dishabituate to a role reversal between chaser and chasee. A second experiment shows that in dishabituating to the role reversal, 8-10-month-olds do base this discrimination on relational information between the two discs and not merely on the contrast between their respective vitality or discrete dynamic. By the age of 8-10 months, infants demonstrate sensitivity to information specifying what one disc does to the other, at a distance. These findings point to important changes in perceptual-cognitive development and are discussed in the context of a well described key transition in social-cognitive development occurring at around 9 months of age.