INFANT COLOR-VISION - TEMPORAL CONTRAST SENSITIVITY FUNCTIONS FOR CHROMATIC (RED GREEN) STIMULI IN 3-MONTH-OLDS/

In order to investigate the development of temporal contrast sensitivi ty functions (tCSFs) for chromatic (red/green) stimuli, we obtained ch romatic contrast thresholds from 3-month-old infants and adults using behavioral techniques, Stimuli mere moving or counterphase-reversing s inusoidal gratings of 0.25c/deg. Five temporal frequencies were used: 0.7, 2.1, 5.6, 11 and 17 Hz (corresponding speeds = 2.8, 8.4, 22, 44 a nd 67 deg/sec), In order to compare chromatic results with those obtai ned under luminance-defined conditions, luminance tCSFs were also obta ined from adults, and previously obtained infant luminance tCSFs mere used (from Dobkins & Teller, 1996a), In accordance with previous studi es, adults exhibited bandpass luminance tCSFs with peaks near 5 Hz and lowpass chromatic tCSFs that declined rapidly at temporal frequencies greater than 2 Hz, and the two curves crossed one another near 4 Hz. By contrast, infants exhibited bandpass rather than lowpass chromatic tCSFs with peaks near 5 Hz, These chromatic curves were quite similar in peak frequency and general shape to previously obtained infant tCSF s for luminance stimuli, Moreover, both chromatic and luminance tCSFs in infants were found to be quite similar in peak and shape to luminan ce tCSFs observed in adults, These findings point to the possibility t hat, for 3-month-old infants, both chromatic and luminance stimuli are detected by the same underlying mechanism under these conditions, We propose that such a mechanism is probably a physiological pathway domi nated by magnocellular input, Earlier studies of infant color vision a re discussed in this context, (C) 1997 Elsevier Science Ltd.