Memory in visual search is task-dependent in both 2D and 3D environments

Abstract

Previous studies have indicated the effect of memory for both context and targets on search in 2D images of naturalistic scenes. However, recent results in 3D immersive environments failed to show much effect of context (Li et al., JOV, 2014). To examine whether this reflects differences between 2D vs. 3D environments, we ran a 2D experiment designed to parallel our previous 3D virtual reality environment. Subjects viewed 2D snapshots taken from the two rooms in the 3D immersive environment and then searched those images for a series of targets. The number of fixations required to locate the targets improved rapidly and was similar in both 2D and 3D environments. Interestingly, most of the improvement reflects learning to choose the correct room to look for a given target. Once in the correct room, search is very rapid and objects were located within 3-5 fixations in either environment. Previous exposure (one minute) to the context did not facilitate subsequent search. This was true for both 2D and 3D. In addition, there was little or no effect of experience with the environment on subsequent search for contextual objects in the scene. Even after 24 search trials, the number of fixations required to locate contextual objects in the room was close to values found with no experience. Incidental fixations made during previous trials also do not seem to benefit search much (though a small effect is detectable). Thus, search in both 2D and 3D environments is very comparable, and the primary effect of experience on search depends on task relevance (i.e., previously searched objects are easily remembered but not otherwise). We speculate that the effects of context either require much more extensive experience, or else a pre-exposure that immediately precedes the search episode. Meeting abstract presented at VSS 2015