chapter  8
Intercepting accelerating projectiles
ByNICOLAS BENGUIGUI, HUBERT RIPOLL
Pages 14

This conclusion was later questioned by Rosenbaum (1975) in his analysis of the nature of Gottsdanker’s experimental task. According to Rosenbaum, it is conceivable that the incapacity of the participants to pursue the accelerating projectile was due to the complexity of the task itself, rather than to a general incapacity to perceive (and act on) a projectile’s accelerating movements. To eliminate this ambiguity, Rosenbaum sought to diminish the motor response component by using a prediction-motion task in which the participant only had to press a switch to indicate his/her estimation of the moment of arrival of a ball at a target after the occlusion of the final part of the ball’s trajectory. In the second experiment reported, three constant velocities (0.19, 0.43, and 0.73 m/s) and three accelerations (0.23, 0.39, and 0.44 m/s2) were used. The participants were as precise in their estimates of constant velocities as for accelerations, suggesting that people

are able to follow and estimate arrival of an accelerating projectile. Nevertheless, there are still some remaining questions about the generality of the results, since the lack of difference between the two conditions could have been due to the relatively low rates of acceleration used.