| Visual search occurs while one is looking for specific items in a complex visual scene. This task is commonly performed in the real world. Because visual search is such an important part of our daily experience, visual search has been extensively studied in laboratory settings. Generally, laboratory investigations involving visual search tasks have utilized artificial, unnatural stimuli which include very simplistic targets on blank backgrounds. Using stimuli that were more complex and continuous, and thus more naturalistic, Wolfe (1994) found that conjunctive search on complex backgrounds is highly efficient. He concluded that models of visual search based on laboratory data can be generalized to "real world" situations. Three-dimensionality, an additional naturalistic feature, was investigated by Enns and Rensink (1990b). They found that rapid, preattentive processing was not limited to simple, non-conjunctive features which implied a two dimensional (2-D) perspective.;This study employed more naturalistic, continuous stimuli, similar to Wolfe' s (1994). However, unlike Wolfe' s, the stimuli also included three-dimensional (3-D) cues such as shading, linear perspective, and direction of lighting. This experiment used a forced-choice method, mixed design to investigate the effect of target type (2-D vs. 3-D), background type (blank, complex, or complex with cues), number of distractors (5, 10, or 15), target presence or absence, and implied lighting direction (left or right) on visual search. Although there was a trend in the blank condition, analysis of the data showed that 3-D targets were not processed more rapidly than 2-D targets. Namely, both seemed to lead to serial searches. Therefore, Enns and Rensink' s work was not replicated. However, Wolfe's conclusion that research which used isolated stimuli on blank backgrounds can be generalized to more complex situations was supported. |
