Harrison Neil R, Wuerger Sophie M, Meyer Georg F
Department of Psychology, Liverpool Hope University, Liverpool, UK.
J Vis. 2010 Dec 16;10(14):16. doi: 10.1167/10.14.16.
For moving targets, bimodal facilitation of reaction time has been observed for motion in the depth plane (C. Cappe, G. Thut, B. Romei, & M. M. Murray, 2009), but it is unclear whether analogous RT facilitation is observed for auditory-visual motion stimuli in the horizontal plane, as perception of horizontal motion relies on very different cues. Here we found that bimodal motion cues resulted in significant RT facilitation at threshold level, which could not be explained using an independent decisions model (race model). Bimodal facilitation was observed at suprathreshold levels when the RTs for suprathreshold unimodal stimuli were roughly equated, and significant RT gains were observed for direction-discrimination tasks with abrupt-onset motion stimuli and with motion preceded by a stationary phase. We found no speeded responses for bimodal signals when a motion signal in one modality was paired with a spatially co-localized stationary signal in the other modality, but faster response times could be explained by statistical facilitation when the motion signals traveled in opposite directions. These results strongly suggest that integration of motion cues led to the speeded bimodal responses. Finally, our results highlight the importance of matching the unimodal reaction times to obtain response facilitation for bimodal motion signals in the linear plane.
对于移动目标，在深度平面的运动中已观察到反应时间的双峰促进作用（C. 卡普、G. 图特、B. 罗梅伊和M. M. 默里，2009年），但尚不清楚在水平面中对于视听运动刺激是否观察到类似的反应时间促进作用，因为对水平运动的感知依赖于非常不同的线索。在这里，我们发现双峰运动线索在阈值水平导致了显著的反应时间促进作用，这无法用独立决策模型（竞赛模型）来解释。当超阈值单峰刺激的反应时间大致相等时，在超阈值水平观察到双峰促进作用，并且对于具有突然开始运动刺激和具有静止期后运动的方向辨别任务观察到显著的反应时间增益。当一种模态中的运动信号与另一种模态中空间共定位的静止信号配对时，我们没有发现双峰信号的加速反应，但是当运动信号沿相反方向传播时，更快的反应时间可以用统计促进来解释。这些结果强烈表明运动线索的整合导致了加速的双峰反应。最后，我们的结果强调了匹配单峰反应时间对于在线性平面中获得双峰运动信号的反应促进作用的重要性。
