Abstract
It is obviously advantageous to continuously adjust one's movements if a target that one wants to intercept moves in an unpredictable manner. We examined whether continuous visual control is also useful for intercepting targets that move predictably. We have previously argued that the accuracy with which people hit moving targets is close to what one would expect from the known limits of human vision. This argument obviously rests on our having chosen the correct measures for representing human vision. We therefore designed the present study to directly examine to what extent continuously controlling one's movements on the basis of updated visual information is beneficial when intercepting targets that move in a completely predictable manner. Subjects hit virtual targets as they passed a goal. Just before reaching the goal the target could briefly disappear from view. This was achieved by giving a section of the surface across which the target moved (just before it reached the gap) the same colour as the target. The advantage of making the target disappear in this manner is that subjects can anticipate from the beginning of each trial when the target will disappear, so they can plan their movements in accordance with the time that the information will be available. Both the accuracy and the precision with which the subjects hit the target were lower if the target briefly disappeared from view just before being hit. The extent to which the precision depended on the time for which the target was invisible is consistent with predictions based on continuous control and the limits of human vision. Thus we can conclude that it is advantageous to have accurate visual information throughout an interception movement, even if the target moves completely predictably, because the resolution of vision is a limiting factor when intercepting moving objects.