Problems in depth perception : perceived size and distance of familiar objects.

PDFTech ReportAM 66-22DOT/FAA/AM-66/22Depth perceptionDistance perceptionSizeDepthDistanceVisionField of visionVision testsDynamic testsStatic testsNight visionLightingBrightnessCalibrationJudgment (Human characteristics)Human subject testingUnited StatesCivil Aerospace Medical InstituteGogel, Walter C.Mertens, Henry W.United States. Office of Aviation MedicineNTL-AVIATION-AVIATIONUS Transportation CollectionJudgments of the distance of familiar objects, especially other aircraft, are critical aspects of flight safety. In this study, the perception of distance as a function of the retinal size of a familiar object was investigated by simulating a stationary or a radially moving playing card in an otherwise dark visual field. When different observers were first presented with the different sizes of the stationary object, a relation between retinal size and perceived distance occurred only if perceived size was taken into consideration and only for the largest two of the three retinal sizes used.It seems that familiar size was a cue to perceived absolute distance when the simulated distances were approximately 3 feet or less, but not approximately 6 feet from the observer. Judgments of the distance of subsequent static presentations of cards, while usually more veridical than first presentations, were found to be dependent upon distance judgments made in the prior presentations. The importance of interactions between presentations or within changing presentations was reflected in the modifications of the dynamic adjustments that resulted from using different starting sizes.The results from this experiment support the view that relational distance cues occurring between successive or sequential presentations are dominant over absolute distance cues occurring with respect to a single object