Abstract
In a traditional dual-task paradigm, performance typically suffers in both tasks compared to performance on either task alone. However, paradigms in which dual task performance exceeds single task performance have gained a lot of attention in recent years. In one such example, Motoyoshi et al. (2014), found dual-task enhancement in a direction discrimination task that used Random Dot Kinematograms (RDKs) when a digit-identification RSVP task was administered simultaneously. They attributed this finding to a reduction of surround suppression that was caused by performing the dual task. We sought to replicate this finding. We used a staircase procedure to measure dot coherence thresholds in three conditions: 1) RDK with simultaneous RSVP stream, where participants reported the two numbers in the RSVP stream and then reported RDK direction; 2) RDK with simultaneous ignored RSVP stream, where participants reported only RDK direction; and 3) RDK presented alone, where participants reported the direction of the RDK. The first two conditions were similar to those used by Motoyoshi et al. (2014); condition 3 was added to determine the impact of including an ignored, centrally-fixated RSVP stream. Each participant completed all three conditions in a randomized order. In contrast to the pattern of results found by Motoyoshi and colleagues, coherence thresholds in the dual-task condition were significantly higher than the two single task conditions (which did not significantly differ from one another).The reasons for the contradictory findings are unclear, but our findings suggest that it may be premature to conclude that sensitivity to RDK direction is enhanced by dividing attention between two tasks.
Meeting abstract presented at VSS 2016