Fifteen Macaca nemestrina monkeys ranging in age from 2 weeks to 3 years participated. We varied the proportion of dots that carried a coherent motion signal over a range of spatial and temporal displacements. Motion sensitivity develops over a similar time course to contrast sensitivity in infant monkeys.
Slow speeds show greater change with age than fast speeds.
Overall sensitivity to motion continues to improve up to at least one year of age. Optimal dot displacement at each age was correlated with development of spatial resolution. We conclude that the normal development of motion sensitivity and the motion sensitivity of amblyopes, as measured by this direction discrimination task, are related to the development of spatial vision.