Four-Month-Olds’ Discrimination of Optic Flow Patterns Depicting Different Directions of Observer Motion
Rick O. Gilmore and Heather J. Rettke
Department of Psychology, Pennsylvania State University

One of the most powerful sources of information about spatial relationships available to mobile organisms is the pattern of visual motion called optic flow. Despite its importance for spatial perception and for guiding locomotion, very little is known about how the ability to perceive one’s direction of motion, or heading, from optic flow develops early in life. In this article, we report the results of 3 experiments that tested the abilities of 4-month-old infants to discriminate optic flow patterns simulating different directions of self-motion. The combined results from 2 different experimental paradigms suggest that 4-month-olds discriminate optic flow patterns that simulate only large (>32B0) changes in the direction of the observer’s motion through space. This suggests that prior to the onset of locomotion, there are limitations on infants’ abilities to process patterns of optic flow related to self-motion.

Quicktime Movies (download files to harddrive before playing):

hab0deg.mov
A QuickTime movie depicting 0 degrees (forward) motion along a ground plane similar to that used in Experiments 1 and 2. In the actual experiment, this animation looped continuously in time.

hab180deg.mov
A QuickTime movie depicting 180 degrees (backward) motion along a ground plane similar to that used in Experiments 1. In the actual experiment, this animation looped continuously in time.

hab16deg.mov
A QuickTime movie depicting 16 degrees motion along a ground plane similar to that used in Experiment 2. In the actual experiment, this animation looped continuously in time.

fpl16deg.mov, fpl32deg.mov, fpl64deg.mov
QuickTime movies with paired optic flow patterns depicting motion along the anterior/posterior axis on one side and optic flow that alternated between anterior/posterior motion and movement 16 degrees, 32 degrees, and 64 degrees from that axis on the other side. This type of display was used in Experiment 3.