Abstract
Understanding the emergence of mature motion processing requires knowledge about the statistics of the visual input that infants and adults are exposed to and how these change across development. Here we study the optic flow experienced by infants and their mothers during locomotion.
Methods. We analyzed head-centered optic flow from (N=6) mother/infant dyads who both wore head-mounted eye trackers that provided a scene camera video stream at 30 Hz. Optic flow was estimated from these videos and fed into a neural model of flow pattern sensitivity for three categories: Expansion/contraction, laminar, and clockwise/counterclockwise (Duffy & Wurtz, 2001). Spectra of the occurrence of these patterns were computed.
Results. Pooled over all 12 subjects 27% of the frames contain expansion flow, 3% backward flow, 15% clockwise, 14% counterclockwise, and 41% laminar flow. Five infants show a frequency of laminar flow around 1.5 Hz. Four mothers show the same frequency in laminar flow; however, with a larger spread around 1.5 Hz. In 5/6 cases, flow velocities are higher in videos from infants than those from mothers. But, we did not find substantial differences in the distribution of flow patterns between infants and their mothers.
Conclusion. Flows experienced by infants in passive locomotion and the adults who are carrying them are similar, including temporal oscillations near 1.5 Hz that may be related to the mother’s gait cycle shared by infants. Most infants experience higher flow speeds than adults perhaps due to reduced stability of the head. Future work will examine retinal flow speeds
Meeting abstract presented at VSS 2012