FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-63/20

Title and Subtitle: The visual perception of spatial extent

Report Date: September 1963

Authors: Gogel WC

Abstract: This study was concerned with the manner in which perceived depth and perceived frontoparallel size varied with physical distance and hence with each other. An equation expressing the relation between perceived frontoparallel size and physical depth was developed and applied to frontoparallel size judgments determined with four observers under two viewing conditions.

Using the same equation and an expression of the size-distance invariance hypothesis, an additional equation was developed whcih related perceived and physical depth. The additional equation, when applied to judgments of perceived depth from the same observers under the same viewing conditions, produced results not in agreement with those expected from the size-distance invariance hypothesis.

This is interpreted as evidence against the validity of the size-distance invariance hypothesis in the usual form. The results from the apparent depth judgments also were applied to the problem of the nonveridicalty of the perceptual bisection of depth intervals.

Key Words: perceived depth, frontoparallel size, physical distance, size-distance invariance hypothesis

No. of Pages: 13