Infant perception of angular relations

The ability of infants to perceive an angle as the relationship between two lines as opposed to independent line segments was examined in 6- and 14-week-old infants. Sixteen infants at each age were habituated to a single angle and then tested with four stimuli designed to differentiate between perception based upon angularity versus the orientation of the line segments. 14-week-old infants dishabituated only to a change in angle and not to a change in orientation. However, the 6-week-old infants did the opposite, dishabituating only to a change in orientation. These results supported the claim that 2- to 4-month-old infants perceive angular relations but tended to refute the claim that this ability is innate. Instead they may indicate an important developmental shift in perceptual ability sometime after 6 weeks of age.