Abstract
Dynamic vision must balance the need to accumulate sensory evidence over time and maintain stability of the current perceptual representation. Those opposing needs of the visual system can be subserved by an intricate interplay between rapid saccadic eye movements to and longer lasting fixations on the relevant parts of the visual environment. Here we investigate whether eye movements influence the ability to integrate successive visual input over time. We took advantage of a temporal integration paradigm that requires observers to perceptually bridge a short temporal gap between two rapid visual displays (missing element task: Di Lollo, 1980). We adjusted the temporal interval (24 ms) to threshold performance and then varied the temporal asynchrony between the onset of a fixation following a horizontal eye movement (8째 visual angle from center) and the presentation of visual displays. The visual stimuli were presented at several time points within the lifetime of a typical fixation (0-25, 26-50, 51-75, 76-100 ms) or later in time (500-525 ms) with respect to fixation onset. As a control condition, observers had to detect the missing element within a combined presentation of both displays at the same time rather than temporally integrate information across displays. Temporal integration improved gradually within the first 100 ms from fixation onset and remained stable at predicted threshold performance later in time. In the control condition, however, detection was at ceiling independent of fixation to stimulus onset asynchrony. These results show that, unlike detection, the ability to integrate visual information over time depends on a rapid temporal window (~100 ms), reset by eye movements. Such a temporal integration window could provide stability of the current percept early within the lifetime of each new fixation.
Meeting abstract presented at VSS 2014