Abstract
The attentional blink (AB) is a well-studied phenomenon in which a second target in a rapid serial visual presentation (RSVP) stream is more difficult to identify when it appears about 300 ms after the first target. Models of the AB attribute the effect to attentional bottlenecks at various levels of target processing. An independent line of oculomotor research shows that microsaccades quiesce in anticipation of a target and then resurge ~200-300 ms after target appearance. Furthermore, microsaccades can reduce target visibility because of excessive retinal-image motion or saccadic suppression. The coincidental timing of the microsaccade resurgence and the typical AB suggested to us that these events might be related. To produce AB, observers performed a task in which they detected a letter in one of two RSVP streams located 3 deg to the left and right of the fixation point. In each RSVP stream, a new character appeared every 100 ms On one-half of the trials, a second letter target appeared after a variable number (0-5) of intervening numerals. Eye movements were recorded at 1000 Hz with an EyeLink 1000 eye tracker while observers performed the task. Microsaccades (saccades with amplitudes < 1.0 deg) were detected offline using the Eyelink analysis software and visual inspection. We found that the timing of microsaccade occurrence was correlated with the drop in performance characteristic of the AB function. Moreover, when the RSVP streams were embedded in a larger stimulus (6 peripheral dots at the same eccentricity as the RSVP streams creating a circular object) both the AB and microsaccade rates were reduced. The results suggest that the occurrence of microsaccades may contribute to the AB, providing an alternative explanation for this phenomenon.
Meeting abstract presented at VSS 2018