Ocular mechanisms in internally directed cognition

Internally directed cognition represents a crucial part of everyday cognitive activities (e.g., thinking about the past, planning future events, daydreaming). Recent evidence suggests that internally and externally directed cognition differ clearly in eye behavior, rendering eye-tracking a promising approach for the objective assessment of attention direction. However, differences in eye behavior appear to be task-specific, as they result from the perceptual decoupling from the actual sensory environment and coupling to ongoing internal events. So far, a systematic investigation of the determinants of perceptual decoupling and internal coupling processes is still missing but would be highly needed to better understand these ocular mechanisms and eventually be able to exploit eye behavior for the objective identification of internal attention. The main research questions of this project thus are: How does perceptual decoupling in top- down and bottom-up driven eye behavior depend on the type and relevance of the perceptual activity, as well as on the workload and modality of the internal activity? How does internal coupling depend on the type and feature representation of the internal activity as well as on the vividness of imagination? What eye parameters qualify as particularly sensitive and specific indicators of internal attention? With a total of ten eye-tracking studies, this project systematically investigates the dependability of perceptual decoupling effects across different forms of top-down eye behavior (i.e., smooth pursuit eye movements, voluntary saccades, task-evoked pupillary response, and fixation disparity), and different forms of bottom-up eye behaviors (i.e., pupillary light response, optokinetic nystagmus, reflexive saccades) and varies several factors including task load and modality. Moreover, it investigates the dependability of internal coupling effects across different eye behaviors (i.e., pupil dilation to imagined luminance, saccadic activity to imagined movements and recalled positions, and fixation disparity to imagined distance). This project undertakes the first extensive and systematic investigation of perceptual decoupling and coupling effects in goal-directed internal cognition. It will deepen our understanding of the ocular mechanism underlying sustained internally directed attention and enable the development of an objective, continuous indicator of internal attention based on eye-tracking. Such an objective attention index would have large application potential for basic research (e.g., study of attentional dynamics in higher cognition), applied and clinical research (e.g., study of sustained attention in learning, vs. attention deficits), as well as for economic applications (e.g., unobtrusive assessment of attention focus and alertness e.g. in the context of driving or education).