| Past studies on visual working memory (WM) have inspired the hypothesis that people use WM to temporarily retain a limited amount of visual information from their environment for current task performance (e.g., Vogel, Woodman, & Luck, 2001). According to this hypothesis, information that is retained is stored in the form of independent object files, each containing all the features of a single object. However, the results of these past studies are difficult to interpret, and the assumptions of the object-file hypothesis have not been carefully tested. In this dissertation, I present a model of performance for a visual change-detection task based on the premise that visual WM stores object files. This model makes quantitative predictions regarding performance in the task and provides estimates of visual WM capacity. I then describe new experiments that test several assumptions of the model. The qualitative results of the experiments and the quantitative consistency between predicted and observed data suggest that people have independent storage for approximately three object files in visual WM. |
