Abstract

The chromatic discrimination ability of 1- and 2-month-old infants was examined using a forced- choice preferential looking technique. Eight degree test circles located 30° right and left of center were embedded in a 547-nm field. Each infant was tested at either 420, 450, 490, 547, or 650 nm using eleven intensity levels spaced 0.1 log unit apart. In general, 1-month-old infants failed to show evidence of the ability to make these heterochromatic discriminations over at least part of the intensity range. In contrast, 2-month-olds usually succeeded at all intensities of the heterochromatic stimulus conditions. These between-subject trends were also confirmed on a within-subject basis. Typically, infants who failed to discriminate showed a systematic U-shaped pattern of percent correct. When these dips were compared to adult brightness matches, a consistent pattern emerged. Generally, minima for 650 nm were a few tenths of a log unit higher and for short test wavelengths a few tenths of a log unit lower than the average adult brightness match. These data can be interpreted to indicate that the infants' brightness matching function differs from the adult function for these stimulus combinations.

© 1985 Optical Society of America