CMU Psychology Dissertation Defense
Title: The Microgenesis of Object-based vis-à-vis Space-based Visual Attention
Presenter: Linda Moya
Location: Baker Hall 154R
Abstract: Visual cognition involves processes such as selective attention and object perception that exist at the intersection of perception and cognition. This research focuses on visual selective attention and the set of processes that determine how some subset of the visual input is selected for further cognitive processing. It also investigates perceptual objects as candidate units on which attentional selection operates. Using a well-established behavioral paradigm together with EEG, MEG and MRI structural neuroimaging, this research investigates the microgenesis of object-based vis-à-vis space-based attention: how attentional cognition evolves across time and space, elucidating the spectral characteristics along the way. The results suggest that selective attention is in part comprised of a set of oscillatory processes including the alpha gating/inhibition process and the theta communication control process. Widespread posterior alpha-band oscillatory activity is interpreted as activity that inhibits task irrelevant areas in order to enable only attended stimuli to be further processed. Widespread theta-band activity, which interacts with hemifield presentation side, is interpreted as a long-range communication process in the attentional network, enabling communication between frontal and more posterior areas, and between hemispheres. The results also suggest a time-course of faster processing for targets presented in the left versus right hemifields, lending support to and providing a specific manifestation of previous findings of right hemisphere dominance in selective attention. In summary,the results reveal the microgenesis of object-based vis-à-vis space-based attention in terms of these oscillatory processes, and how they evolve in time and across space.