A modified card procedure for measuring human infant color vision

To improve test efficiency, we modified our previously introduced contrast/color card test by including a patterned test stimulus and reducing the number of stimuli in both experimental phases. Compared with the prototype, completion rate improved substantially (79 vs. 37%) but test time decreased only modestly (19 vs. 21 min). Achromatic contrast discrimination improved threefold (mean, 0.06 vs. 0.20 log units), but the percentage of 2-month-old infants who discriminated (from gray) 660-nm red (86 vs. 80%) and 580-nm yellow (52 vs. 55%) was consistent. In addition, 48% discriminated 574-nm yellow-green. Moreover, because 88% of infants' failures included the respective adult brightness/luminance match, a small range of relative luminances is adequate for testing infant color vision.