INFANT USE OF RELATIVE MOTION AS INFORMATION FOR FORM - EVIDENCE FOR SPATIOTEMPORAL INTEGRATION OF COMPLEX MOTION DISPLAYS

Previous studies of infants' ability to integrate and to utilize relat ive motion as information for form in the absence of structural cues h ave primarily involved motions that are uniform in rate, direction, an d path within the form to be constructed. In the present study, we exa mined infants' ability to integrate relative motion information from m otions that are nonuniform along these dimensions, and from this integ rative process to construct a coherently rotating two-dimensional form . Infants' ability to integrate nonuniform motion was measured with re gard to their ability to discriminate the rotating form from a noncohe rent control display containing the same absolute motions. The results showed that discrimination of the coherent and incoherent displays wa s not demonstrated until 7 months of age. Two additional experiments w ere conducted to rule out the possibility that this discrimination was based on the detection of local regions of coherence, rather than the perception of the global rotating form. In both experiments, the resu lts did not support discrimination based exclusively on local cues alo ne. From the combined results of all three experiments, we conclude th at infants demonstrate the capacity to integrate the information conta ined within nonuniform trajectories into a coherent structure by 7 mon ths of age.