Viewpoints and Frames of Reference in Spatial Memory

Abstract

<p>Previous human behavioral research has provided support for the existence of different frames of reference utilized during spatial processing that can be dependent or independent of the observer. These are known respectively as egocentric and allocentric frames of reference. However, it has been difficult to dissociate these two different processes under realistic conditions. Importantly, how these frames of reference are influenced by the visual and non-visual information is not well understood. Therefore, the studies of this thesis evaluated spatial processing utilizing realistic and ecologically valid stimuli in environments of different scales, while systematically manipulating the visual and non-visual information available during learning. We demonstrated that non-visual information generated by actively walking through an environment leads to more egocentric processing, whereas the same visual motion information presented passively via a video leads to more allocentric processing (Chapter 2). Further, characteristics of the visual scene can also influence how it is processed, dependent on the strength of the verbal identity of the features in the environment (Chapter 3). Specifically, in a small room environment subject’s representations of corners-to-corners (corners do not have an obvious verbal component) were not as strongly encoded relative to each other in comparison to objects-to-objects (objects with an obvious verbal identity ). Finally, we demonstrated differential influences of non-visual information dependent on whether the features in the visual scene were more allocentrically processed or egocentrically processed (Chapter Four). Specifically, when different features of layouts are made distinguishable by their identity, this lead to more allocentric processing whereas when different features are made distinguishable by their relative position, this lead to more egocentric processing. Further, non-visual information made available during spatial updating when the observer is changing viewpoints benefitted tasks focused on differentiating changes to objects’ identity and less so for differentiating changes in relative object position.</p>