Abstract
The present investigation examined the effects of display extent and object velocity on the accuracy of target arrival estimation after target disappearance. After viewing a target which moved across a variable length display aperture at one of three target velocities and then disappeared, 5s estimated the time at which the target would reach a fixed destination. Elapsed time between time of target disappearance and S's response was recorded. Each of 15 5s made 90 such judgments. It was found that target velocity was a significant source of variation but that display extent did not reach statistical significance. The interaction between target velocity and display extent was also statistically significant. When time estimates were converted to velocity estimates and the standard deviation of estimate was plotted against mean velocity estimate, a linear function similar to those reported by Brown (1960, 1961) was obtained.