The long-term objective of the present proposal is to continue studies of color vision in infants. Three techniques will be used: forced choice preferential looking (FPL), visual evoked potentials (VEP), and directionally appropriate eye movements (DEM). Potential clinical utility could include spin-offs of diagnostic techniques for evaluating the development of vision and visual pathways in infant patients (c.f. the Teller Acuity Cards previously developed in this laboratory). Five series of experiments are proposed. 1. Cone metamers and cone absolute sensitivities. The outer segments of immature cones in the infant fovea are very short; thus, infants' foveal color matches should differ from those of adults. VEP's will be used to determine color matches for the infant's central and peripheral vision. In addition, FPL will be used to determine infant threshold-vs.- intensity (t.v.i.) curves, with various test and background wavelengths chosen to reveal the absolute thresholds of the various cone types. 2. Spectral efficiency and the transition from scotopic to photopic vision. Current data suggest that infant vision may be more """"""""rod-dominated"""""""" than is adult vision. This hypothesis will be examined by testing infants' luminous efficiency functions for selected wavelengths, across the adult mesopic luminance range. 3. Chromatic discrimination at various light levels. Again because of foveal immaturities, at a fixed luminance level infants' foveal cones catch far fewer quanta than do those of adults. This idea will be pursued by studying infant and adult chromatic modulation thresholds as a function of luminance. Follow-up studies include a set of basic infant chromatic discrimination experiments at optimal luminance levels. 4. Color codes: privileged versus redundant. Nothing is known about the """"""""cardinality"""""""", or privilegedness versus redundancy of color codes in infants. FPL will be used to examine sets of discrimination ellipses in the luminance-vs-r/g plane (and perhaps other planes), to see whether all discrimination ellipses within a single plane have common major/minor axis orientations. In a second approach, we will study cross-adaptation and/or cross-masking between luminance and chromatic stimuli. 5. Color and motion. A quadrature motion paradigm will be used to determine whether infants can code be direction of motion with their chromatic channels in isolation. Follow-up studies include studies of motion/detection ratios, and the coherence or non-coherence of motion signals in chromatic plaids.
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