社会与工程心理学研究室知识库

摘要：本研究采用事件相关电位（Event related potential, ERP）技术探索把手放在刺激旁边是否会提升持续性注意。研究采用三刺激视觉oddball范式。在该范式中有三类刺激，分别为目标刺激，分心刺激和标准刺激，其中目标刺激和分心刺激出现的比例均为12%，而标准刺激刺激出现的比例为76%。被试需要在目标刺激出现时进行按键反应，在其它两类刺激出现时不做任何反应。前人研究发现，目标刺激能诱发一个明显的P3b成分。 P3b成份大约出现在刺激呈现后的300至500 ms，主要分布在中后部（central-parietal）电极，是一种目标驱动的有意注意（voluntary attention），其波幅代表给予目标刺激的注意资源的多少。分心刺激通常会诱发一个比P3b更早且分布更靠前的正成份，称为P3a。 P3a被认为是对新异刺激的朝向反应，是一种刺激驱动的无意注意（involuntary attention）。被试需要在手近（双手放在屏幕两边）和手远（双手放在腿上）条件下分别完成两组任务，每组大约8分钟，并同时记录脑电。行为结果发现手远条件下目标刺激的反应时第二组显著慢于第一组，而手近条件下两组的反应时没有显著差异。与行为结果相一致，ERP结果显示手远条件下目标刺激诱发的P3b波幅第二组显著小于第一组，而手近条件下两组的P3b波幅没有显著差异。该结果说明手近提升了对目标刺激的持续性注意。另外，对分心刺激诱发的P3a波幅分析发现，不管在手远条件下还是在手近条件下第二组的P3a波幅显著小于第一组，但是手近条件下P3a波幅下降程度显著小于手远条件下。该结果说明手近也提升了对分心刺激的持续性注意。然而，对标准刺激诱发的P3成分分析发现，整体上第二组的P3波幅显著小于第一组，且P3波幅的下降程度在手近手远两种条件下没有显著差异。因此，本研究结果说明不管是目标驱动的有意注意还是刺激驱动的无意注意，手近时都能保持得更好。

Abstract:This study used event-related potentials to investigate whether sustained attention can be improved near the hands. Twenty-nine participants performed a three-stimulus visual oddball task, in which they were required to differentiate a rare target stimulus, a rare salience distracter, and a frequent non-target stimulus. Results showed the RT to target increased as task duration increase in hand-distal trials but not hand-proximal trials. Consistently, the target-elicited P3b amplitude decreased with time on task in hand-distal trials but not hand-proximal trials. These results suggest that placing hands near the stimuli improved sustained attention to the target. Moreover, the distracter-elicited P3a amplitude decreased more slowly over time in hand-proximal trials compared with hand-distal trials, suggesting placing hands near the stimuli subserves maintaining attention to salience distracter too. However, the P3 amplitude elicited by standard stimuli was not modulated by hand-stimulus proximity. Thus, placing hands near the stimuli may improve sustained attention to rare stimuli regardless of the stimuli’s task relevance. The present findings may have an application in helping younger children or patients with ADHD to maintain their attention.