Abstract
The ventral and dorsal visual pathways that subserve form and motion processing have been hypothesized to have different developmental profiles (see Atkinson & Braddick, 2011). Using random dot kinematograms, we measured coherence sensitivities to three stimulus types: motion, static form and dynamic (i.e. flickering) form stimuli in typical development. Here, we asked whether sensitivity to coherent form and motion stimuli matures in a similar way. Moreover, since dynamic form stimuli have been described to induce illusory motion, we also asked whether sensitivities to dynamic form follow the development of sensitivities to static form or motion or something in between. We presented dots that moved coherently in a circle (motion stimuli) or formed a circular texture (form stimuli) to adults, 10-13 year olds, 8-9 year olds, 6-7 year olds, and 4-5 year olds. In a staircase procedure, we asked our participants to detect which of two intervals contained the circular movement or pattern. Motion coherence sensitivity showed a steeper increase than static or dynamic form sensitivity with age. Interestingly, 4-5 year olds showed the highest sensitivities to dynamic form stimuli and the lowest sensitivities to motion, suggesting that in young children dot motion and dot flicker are processed differently. In contradistinction, the sensitivities to motion and dynamic form were nearly identical in children 8 years or older. Together, our results suggest that the pattern of sensitivities to dot coherence is immature in children under the age of 7 years.
Meeting abstract presented at VSS 2012