Ma. Thomasson et Dy. Teller, Infant color vision: sharp chromatic edges are not required for chromatic discrimination in 4-month-olds, VISION RES, 40(9), 2000, pp. 1051-1057
In our previous demonstrations of chromatic discrimination in infants, we h
ave used test and surround fields of different chromaticities that abutted
each other at sharp chromatic edges. In order to see whether sharp chromati
c edges are necessary for infants to make chromatic discriminations, 16-wee
k-old infants were tested with three stimulus configurations in which sharp
chromatic edges were eliminated. The three edge manipulations involved bla
ck borders, a dark surround, or blurred edges around the chromatic test fie
ld. In each case red, green, and violet test fields were used. Although per
formance decreased when sharp chromatic edges were eliminated, observers' p
ercent correct scores remained clearly above chance for eight of the nine d
iscriminations (three colors x three edge manipulations). We argue that all
three edge manipulations reduce the likelihood of mediation of chromatic d
iscrimination by M (magnocellular) cells. These data thus provide evidence
that young infants have functional P (parvocellular) pathways, and use them
for making chromatic discriminations. (C) 2000 Elsevier Science Ltd. All r
ights reserved.