Conscious Access and Attentional Blink during Eye Movements

JUAN E KAMIENKOWSKI; JOAQUIN NAVAJAS; MARIANO SIGMAN

Congreso; XXVII Congreso Anual de la Sociedad Argentina de Neurociencias; 2013

Sociedad Argentina de Neurociencias

When we look at a visual scene, we spontaneously move our eyes producing a set of fixations, separated by ballistic eye-movements or saccades. This work was aimed to study the temporal dynamics of conscious access during eye-movements. To address this issue, we designed a set of gaze-contingent experiments where the fixation duration was under subjects´ control, but constrained to a distribution similar to fixations in natural tasks. We show that conscious access is restricted to a temporal window embedded in the fixations. However, while subjects? visibility is close to perfect during that window, introspective confidence increases with a slower rate. This asymmetry can be regarded as an accumulation of evidence that biases the selection of information, becoming more likely to select items flashed close to the outgoing saccade. When presented a rapid succession of visual stimuli, participants often fail to detect a second salient target, a phenomenon referred as the attentional blink. We show that the blink vanishes when both targets are presented within a fixation (far from the saccadic boundaries) and that it recovers more rapidly in successive fixations. These results support current views that the blink results from a discrete structuring of attention and provide evidence that eye-movements play an important role in the formation of those episodes.