Abstract
In three experiments subjects tracked a dot that oscillated vertically while a rectangular stimulus oscillated horizontally. The pairing of frame and dot motion caused the dot to appear to move on a slant due to induced motion (IM). In the first experiment, subjects made judgments of the apparent slant of the dot's motion and, on separate trials, pointed open loop at the apparent location of the dot at the endpoints of its motion. Both responses were influenced by IM, although the influence on dot location was less than the amount of IM indicated by the slant responses. Results were similar immediately following IM and after a five second delay. In the second experiment, subjects pointed open loop either at the apparent location of the endpoints of the tracked dot's motion or at the apparent location of one of three other briefly flashed dot targets. The pointing responses directed toward the fixated IM target were influenced by IM, although there was no similar influence on responses directed toward the other three targets. In the third experiment, similar measures were obtained while subjects maintained fixation at the location of the tracked dot. Results were similar to those obtained in the second experiment. The results of the three studies are inconsistent with the hypotheses that IM alters the registration of either eye position or trunk position, as misregistration of either would be expected to influence pointing responses directed to either the tracked stimulus or the other briefly flashed targets.