Nature of *representations in spatial working memory.

The goal of this dissertation is to study how multiple locations are represented in spatial working memory. In particular, the focus is on whether spatial locations are represented as part of larger configurations, or whether they are presented independently, as if in isolation, with only absolute positional information preserved. If there is evidence to indicate that representations contain configuration information above and beyond absolute location information, then representations are characterized as configural. The first series of experiments show that when asked to recall sequentially presented locations people preserve configuration information in their representations, only for the shorter sequences. Further evidence for people preserving configuration information formed by spatial sequences comes from increased confusability of sequences forming similar configurations. These configural representations are demonstrated to be orientation-specific, because configurally identical but rotated spatial sequences are easily discriminated. In the second set of studies, I investigate effects of sequence length and sequence path complexity on how well configurations are preserved and whether these influence the precision with which each location is represented. Increased sequence complexity negatively influences how well configuration information is preserved. While complexity does not influence the precision with which each location is represented, an inverse relationship between sequence length and precision suggests that people strategically code longer sequences more coarsely. The third series of experiments investigates how spatial representations change based on task demands and practice. People cannot easily ignore configuration information and represent locations independently, regardless of varying task demands or practice. However, practice at recalling sequentially presented locations does result in superior recall of spatial configurations. The final set of experiments presented in this dissertation extend the research on the nature of spatial representations and address how spatial configuration information is represented along with visual object information. People are shown to effortlessly encode information about spatial layout of simultaneously presented objects, and this in turn is shown to affect their judgments about the visual properties of the objects. This suggests that visual object and spatial configuration information are tightly bound. Overall, it is concluded that representations of multiple locations are configuration-based.Ph.D.Cognitive psychologyExperimental psychologyPsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125304/2/3192584.pd