The Stability Of Color, Location, And Object Presence In Mental Representations Of Natural Scenes
V. Aginsky, Brown University.
M.J. Tarr, Brown University.
R.A. Rensink, Cambridge Basic Research.

Investigative Ophthalmology & Visual Science, 38:1009. 1997. [ARVO 1997; Ft. Lauderdale, FL.]

Purpose. Although observers easily extract the global meaning of natural scenes, it is often the case that they do not notice or remember all of their individual properties. It appears that some scene properties are more readily coded in mental representations than others. We tested the role of three different object properties - color, location, and presence/absence - in scene representations.

Methods. A change detection "flicker" task was used, in which a blank field disrupted a scene display at fixed intervals -- during this blank, an element of the scene was altered. The disruption was assumed to delocalize transients that would normally attract an observer's attention to the changing object. Thus, subjects presumably relied on their visual memory of the scene in order to identify the change. Time to detect each change was measured: a) when a cue was provided regarding the type of change, and, b) when no cue was provided. It was hypothesized that cuing would enhance the procesing of preperties that are normally less stable in scene representations (stability interpretation), and therefore would imporve detection for properties that are otherwise less salient in visual memory.

Results. Results suggest that: 1) There was an overall cuing advantage for color changes relative to location and presence/absence changes; 2) Changes in foreground (detail) elements were detected more rapidly than changes in background (contextual) elements; 3) There was an interaction between the impact of cuing on the types of change and the foreground/background condition.

Conclusions. According to the stability interpretation our results indicate that background color information is not coded as readily as background location or object presence in mental representations of scenes. Overall, these findings confirm the importance of spatial configurations in scene processing -- supporting the intuition that information about the location and presence of objects is more diagnostic of scene categories than is color information.

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