Object and Spatial Working Memory in Visual Search for Multiple Targets

Visual search for multiple targets is especially error prone. One of these errors is called subsequent search misses (SSM) and represents a decrease in accuracy at detecting a second target after a first target has been found. One of the possible explanations of SSM errors is working memory resource depletion. Four experiments investigated the role of different kinds of working memory in SSM errors. The first experiment investigated the role of object working memory using a classical color change detection task. In the second and the third experiments, a modified change detection task was applied, using shape as the relevant feature. In the fourth experiment, a spatial working memory task was used to reveal the role of spatial working memory in SSM. The second and the third experiments revealed interference between working memory and visual search tasks, whereas in the first and the fourth experiments interference was not found. The results are discussed in terms of specific working memory deficit in SSM errors.