Visually perceived location is an invariant in the control of action

Abstract

Weprovide experimental evidence that perceived location is an invariant in the control of action, by showing that different actions are directed toward a single visually specified location in space (corresponding to the putative perceived location) and that this single location, although specified by a fixed physical target, varies with the availability of information about the distance of that target. Observers in two conditions varying in the availability of egocentric distance cues viewed targets at 1.5, 3.1, or 6.0 m and then attempted to walk to the target with eyes closed using one ofthree paths; the path was not specified until after vision was occluded. The observers stopped at about the same location regardless of the path taken, providing evidence that action was being controlled by some invariant, ostensibly visually perceived location. That it was indeed perceived location was indicated by the manipulation of information about target distance-the trajectories in the full-cues condition converged near the physical target locations, whereas those in the reduced-cues condition converged at locations consistent with the usual perceptual errors found when distance cues are impoverished.

The development of path integration: Combining estimations of distance and heading

“…This could either involve navigating to a location that participants have previously seen before being blindfolded (Elliott, 1987;Philbeck et al, 1997), or returning to the starting position of a single-element (Mittelstaedt and Mittelstaedt, 2001) or multielement (Loomis et al, 1993) path. Across such studies, participants are very systematic in the errors that they make, demonstrating the existence of clear nonrandom principles underlying performance.…”

Dissociation between location and shape in visual space.

“…Yet a number of recent studies using "visually directed action", such as blind walking toward a previewed target, have demonstrated that perception of egocentric distance under similar conditions is both linear in physical distance and accurate out to at least 20 m (Elliott, 1986(Elliott, , 1987Fukusima, Loomis, & DaSilva, 1997;Loomis et al, 1992;Loomis, Klatzky, Philbeck, & Golledge, 1998;Philbeck, Loomis, & Beall, 1997;Rieser, Ashmead, Talor, & Youngquist, 1990;Sinai, Ooi, & He, 1998;Steenhuis & Goodale, 1988;Thomson, 1983; for a summary see Loomis and Knapp [in press]). The accuracy with which egocentric distance is perceived appears to conflict with the systematic misperception of shape and extent under similar conditions.…”

Does Energy Expenditure Affect the Perception of Egocentric Distance? A Failure to Replicate Experiment 1 of Proffitt, Stefanucci, Banton, and Epstein (2003)

“…Participants verbally estimated the egocentric distance and diameter of each target sphere. Participants then performed an indirect blind walking task (also called "triangulated walking") to the various targets (Loomis, Klatzky, Philbeck, & Golledge, 1998;Philbeck, Loomis, & Beall, 1997;Thompson et al, 2004). Participants viewed the target and then, while wearing a blindfold, first walked along a straight path oblique to the target and then turned and walked the rest of the way to the estimated target location.…”