Infant direction discrimination thresholds

AbstractAlthough adults can detect direction differences as small as 1 arc degree, the ability of infants to discriminate direction of motion is less clear. This study measures the precision with which 6-, 12-, and 18-week-old infants discriminate direction of motion. Infants viewed random dot kinematograms in which a direction difference between the target and background dots defined a circular target. The target was then placed into continuous motion. An FPL paradigm was used to assess infants’ preference for the target as a function of the direction difference between the target and background dots. Direction discrimination thresholds with a moving target were indeterminate at 6 weeks of age, 22° at 12 weeks of age and 17° at 18 weeks of age. This precision was maintained across different testing conditions. However, performance dropped markedly when dot motion was presented within a flickering stationary target. It was concluded that infants can make relatively fine discriminations of motion direction if given an engaging stimulus