Echolocating distance by moving and stationary listeners

It has long been known that human listeners can echolocate a sound-reflecting surface as they walk toward it. There is also evidence that stationary listeners can determine the location, shape, and material of nearby surfaces from reflected sound. This research tested whether there is an advantage of listener movement for echolocating as has been found for localization of emitted sounds. Blindfolded participants were asked to echolocate a 3 x 6 ft wall while either moving or remaining stationary. After echolocating, the wall was removed, and participants were asked to walk to where the wall had been. Results showed that participants were somewhat more accurate with moving than stationary echolocation for some distances. A follow-up experiment confirmed that this moving advantage was not a function of a specific type of training or the multiple stationary positions available during moving echolocation. This subtle moving advantage might be a function of echoic time-to arrival information.