Infant sensitivity to radial optic flow fields during the first months of life.
Little is known about the development of the sensitivity for "optic flow," a large-scale pattern perceived during locomotion. The present study aimed to examine infants' coherence thresholds to radial optic flow motion during the first months of life. Using a forced-choice preferential looking technique, infants' sensitivities were measured with a moving radial stimulus varying in coherence on one side and a corresponding non-directional radial noise pattern on the other. Coherence thresholds for 11 infants from each of 2, 4, 6, 8, and 10 months of age groups were studied by a constant stimuli method. In the second experiment, seven infants were followed longitudinally (tested at 2, 4, 6, and 8 months) using the same stimuli. Results of both studies demonstrated significant improvement for the sensitivity of expanding radial motion during the first months of life. Finally, the 2 directions of radial motion were tested (expanding and contracting) for participants followed longitudinally (from 2 to 8 months). Data showed superior sensitivity for expansion versus contraction direction of motion. This dissociation may suggest that sensitivity to direction corresponding with forward locomotion (expansion) develops at a faster rate than the opposite direction encountered when moving backwards (contraction). The sensitivity improvement for expanding patterns likely reflects the maturation of cerebral areas subtending motion integration in infancy.
Brosseau-Lachaine
Odile
O
Visual Psychophysics and Perception Laboratory, School of Optometry, University of Montreal, Montreal, QC, Canada. odile.brosseau-lachaine@umontreal.ca
Casanova
Christian
C
Faubert
Jocelyn
J
D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008124:Locomotion / Q000502:physiology*; D008297:Male; D009039:Motion Perception; D010775:Photic Stimulation; D012684:Sensory Thresholds; D014793:Visual Cortex / Q000254:growth & development*