Reproduction of Object Shape is More Accurate without the Continued Availability of Visual Information

Abstract

An unfamiliar configuration lying in depth and viewed from a distance is typically seen as foreshortened. The hypothesis motivating this research was that a change in an observer's viewpoint even when the configuration is no longer visible induces an imaginal updating of the internal representation and thus reduces the degree of foreshortening. In experiment 1, observers attempted to reproduce configurations defined by three small glowing balls on a table 2 m distant under conditions of darkness following 'viewpoint change' instructions. In one condition, observers reproduced the continuously visible configuration using three other glowing balls on a nearer table while imagining standing at the distant table. In the other condition, observers viewed the configuration, it was then removed, and they walked in darkness to the far table and reproduced the configuration. Even though the observers received no additional information about the stimulus configuration in walking to the table, they were more accurate (less foreshortening) than in the other condition. In experiment 2, observers reproduced distant configurations on a nearer table more accurately when doing so from memory than when doing so while viewing the distant stimulus configuration. In experiment 3, observers performed both the real and imagined perspective change after memorizing the remote configuration. The results of the three experiments indicate that the continued visual presence of the target configuration impedes imaginary perspective-change performance and that an actual change in viewpoint does not increase reproduction accuracy substantially over that obtained with an imagined change in viewpoint.

Distance estimation in vista space

“…We have used an egocentric distance estimation task. The spatial representation underlying a blindwalking task or an equal distance task is known to produce different results, and matching a frontoparallel distance with a given sagittal distance leads to a foreshortening in the sagittal direction (e.g., Amorim et al, 1998;Loomis et al, 1996). In light of these method effects, a replication of the present experiments with allocentric distance judgments seems desirable.…”

Observing and engaging in purposeful actions with objects influences estimates of their size

“…Thus, there is support for the idea that we maintain memory representations of size and may use that size representation from memory in subsequent analyses even when an object is present. Also, accurate descriptions of twodimensional spatial arrays at a distance may be disrupted by visual information (Amorim, Loomis, & Fukusima, 1998), suggesting that the memory of images interacts with visual perception when shape and size are estimated.…”

Embodied Perception and the Economy of Action

“…Unlike geographical slant, which is overestimated, egocentric distance tends to be underestimated when assessed by verbal reports or visual matching tasks (Amorim, Loomis, & Fukusima, 1998;Loomis, Da Silva, Fujita, & Fukusima 1992;Norman, Todd, Perotti, & Tittle, 1996). Another dependent measure, blind-walking, tends to be fairly accurate (Loomis et al, 1992;Rieser, Ashmead, Talor, & Youngquist, 1990;Thomson, 1983).…”