Properties and Consequences of Visual Persistence.

The major effort in our laboratory was directed to investigate the ability of subjects to represent and use visual spatial location. One series of experiments was concerned with the effects of expectation of eventsstimuli at different spatial locations, on the performance of observers in different type of tasks. The results indicate that attentional effectschange in sensitivity depend on the attentional instructions as well as on the complexity of the tasks. Another series of studies was carried out to assess the accuracy of perceived relative location as a function of visual yield eccentricity. The goal was to determine to what extend can human pattern recognition abilities be characterized as a translation invariant after appropriate scaling system. visual yield eccentricity. The results indicate that, although translation invariance does not hold, there are regularities in the data that give rise to interesting models of visual representation of distances. Another series of experiments was carried out to determine how people judge the direction of motion and how accurately they predict the final location of a moving target. The somewhat surprising results indicate that the judgement of moving targets yield similar accuracy as those with static stimuli. The implication is that such judgements are performed at a higher level of stimulus representation. The last group of experiments investigated transformations of the mapping between visual and motor spaces. Movement under transformed mapping can be modeled as a solution of simple differential equations incorporating the properties of the transformation.