|
Abstract:
Probabilistic Sensorimotor Processing: Overcoming Uncertainty and Ambiguity to Improve Behavior
Perception and action are critical functions for most animals’ survivals, but to achieve high performance each must overcome uncertainty and ambiguity, both in perceiving the world and planning and executing actions. The following work examines how human behavior minimizes the negative consequences of uncertainty and ambiguity to improve performance in perceptually-guided tasks. 1) An object’s size and distance each influence the angular size of its visual image, rendering distance estimation based on angular size alone an ambiguous task. But, an “auxiliary” sensory measurement of the object’s size can disambiguate the distance. We ran a psychophysical experiment to test whether humans use sensed size when making distance judgments, and found significant improvements in distance perception due to the auxiliary size sensations. 2) Just as size and distance are each impossible to unambiguously estimate given angular size alone, judging the rate that an object’s size changes given only angular size-change rate is also ambiguous. But an auxiliary distance-change rate sensation can be used to disambiguate the size-change rate. We conducted an experiment to evaluate whether humans use the sensed distance-change rate when making size-change judgments, and found significant improvements in size-change perception due to the auxiliary distance-change sensations. 3) Many behavioral tasks have inherent time constraints that limit the time available for perception and action. We tested whether humans are able to adjust the time they devote to each to minimize the negative consequences of uncertainty that originates from perceptual and motor imprecision. We found humans’ timing choices are consistent with the theoretically ideal actor’s choices, and concluded that humans’ implicit knowledge of their perceptual and motor variability is used to make these choices. |