Modeling echo-target acquisition in blind humans

Echolocating organisms ensonify their surroundings, then extract object and spatial information from the echoes. This behavior has been observed in some blind humans, but the computations underlying this strategy remain extremely poorly understood. Here we tracked the movements and echo emissions of an expert blind echolocator performing a target detection and localization task. We found that the precision of responses as well as target acquisition movements depended significantly on the size of the target and availability of active echo cues. The distribution of click directions suggested that the maximal energy of each click was always directed at the target. Our results pave the way toward characterizing human echolocation in the context of other active sensing behaviors, constraining the types of perceptual mechanisms mediating its behavior, and at a practical level, building a quantitative evidence base for optimizing therapeutic training interventions.