Abstract
A fundamental question in neuroscience is how the brain integrates information derived from different cues or modalities into coherent percepts. Many studies have looked at this question from behavioral, computational, and neurophysiological viewpoints. Unfortunately, different integration strategies have been observed in different experiments. We believe that an important reason why investigators have been unable to identify “the cue integration strategy”s is that observers do not use a single, immutable strategy. Rather, they use a collection of context-sensitive strategies that are adaptable in an experience-dependent manner. Evidence of the adaptability of cue integration strategies has been reported earlier, but has only recently begun to accumulate. We study the dynamics of visual cue integration in a tracking / identification task, where subjects track a target object among distractors and identify the target after a short occlusion. Objects are defined by three different attributes (color, shape, size) which change randomly within a singe trial. When the attributes differ in their reliability (two change frequently, one is stable) our results show that subjects rapidly re-weight the different cues putting more emphasis on the stable cue. This effect does not require subjects' awareness of the differential reliabilities of the other cues. The re-weighting takes place in less than one second. Our results suggest that cue integration can exhibit adaptive phenomena on a very fast time scale. We propose a probabilistic model with temporal dynamics that accounts for the observed effect.