Abstract
Eye-fixations elicit a neural response commonly referred to as the lambda potential that is similar to the visually-evoked P1 event-related potential (ERP) component. An outstanding question is whether the lambda potential is influenced by concurrent auditory task demands. To address this question we obtained simultaneous eye-movement and electroencephalographic (EEG) measures during a guided visual search task while parametrically modulating working memory load using an auditory N-back task. Eye fixations were guided across a grid of letters consisting of âLâs (non-targets) at random orientations. Participants were instructed to make a button press when they fixated on the infrequent target letter âTâ. Participants performed the guided fixation task alone, while ignoring binaurally presented digits, or while using the auditory information in a 0, 1, or 2-back task. Our results show that reaction time increased and accuracy decreased in both the visual search task and auditory N-back task as a function of working memory load. Moreover, we found evidence that the amplitude of the fixation-related potentials were affected by auditory working memory demands. These results suggest that active engagement in an auditory task can influence early stages of visual processing and negatively affect visual search performance. The data provide support for a link between cross-modal processing resources.
Meeting abstract presented at VSS 2015