Attention mediates the encoding of duration

Abstract

Attention has been suggested to play an important role in duration processing. Here, we investigated whether attention mediates the encoding of the durations of multiple events by measuring the duration after-effect (DAE) following adaptation to concurrently presented events with different durations. Observers adapted by viewing two streams of Gaussian blobs displayed to the left and right of a central fixation cross. In Experiment 1, blobs in one stream lasted 200 ms while the blobs in the other stream lasted 800 ms. To manipulate attention, observers were instructed to perform a duration-oddball detection task on one of the streams (and ignore the other), while maintaining central fixation. In Experiment 2, observers adapted in three conditions: repetitions of blobs lasting 200 and 400 ms, while performing the oddball task on the 200 ms blobs (Attended: 200 ms, Unattended: 400 ms; A200/U400) or the 400 ms blobs (A400/U200), or to repetitions of blobs that both lasted 400 ms, while performing the oddball task on one of the streams (A400/U400). To measure the DAE, observers completed a cross-modal duration judgment task in which they compared a fixed auditory reference to a visual test stimulus with a varying duration. The results of Experiment 1 reveal that attending to blobs lasting 200 ms caused an after-effect in line with adaptation to 200 ms, while attending 800 ms blobs caused an after-effect in line with adaptation to 800 ms. This shows that the magnitude of the DAE depended on which duration was attended to during adaptation. Experiment 2 revealed no difference between the after-effects when the unattended stimulus lasted 200 ms (A400/U200) and when it lasted 400 ms (A400/U400), demonstrating that the unattended duration does not contribute to the measured DAE. These results show that attention plays a crucial role in selecting which durations are encoded. Meeting abstract presented at VSS 2017