HUMAN ECHOLOCATION AS A BASIC FORM OF PERCEPTION AND ACTION

In this article we discuss known and possible uses of echolocation by humans. We argue that echolocation may be a basic perception-action ab ility of humans. We review studies which suggest that both blind and s ighted humans are capable of substantial precision in the perception o f properties of distal objects, such as distance, size, shape, substan ce, and relative motion. We analyze relations between acoustic pulse a nd echo that may provide information to support these percepts and oth ers. Our analysis predicts echolocation-based sensitivity in humans an d other animals to a number of properties of the animal-environment in teraction. We also discuss echolocation-based acoustic specification o f time-to-contact. We develop a new variable that provides this inform ation and discuss ''acoustic tau s'' recently developed by Shaw, McGow an, and Turvey (1991) and by Lee, van der Weel, Hitchcock, Matejowsky, and Pettigrew (1992). Our analysis suggests that there may be importa nt insights to be gained from an ecological study of echolocation in h umans and other species. We end with suggestions for research derived from our analysis.