Jaśkowski P, Verleger R
Department of Psychophysiology, Pedagogical University of Bydgoszcz, Staffa 1, 85-867 Bydgoszcz, Poland.
Conscious Cogn. 2000 Sep;9(3):435-56. doi: 10.1006/ccog.2000.0461.
If two stimuli need different times to be processed, this difference should in principle be reflected both by response times (RT) and by judgments of their temporal order (TOJ). However, several dissociations have been reported between RT and TOJ, e.g., RT is more affected than TOJ when stimulus intensity decreases. One account for these dissociations is to assume differences in the allocation of attention induced by the two tasks. To test this hypothesis, different distributions of attention were induced in the present study between two stimulus positions (above and below fixation). Only bright stimuli appeared in one position and either bright or dim stimuli in the other. In the two RT experiments, participants had to respond to every stimulus appearing in one of the two positions. Reaction times to bright stimuli were faster when they appeared in the position where dim stimuli were likely to occur. This finding suggests that the allocation of attention was adapted to the asymmetrical arrangement of stimuli, not suggested by explicit instruction. In the two TOJ experiments, the temporal order of stimuli appearing in the two positions had to be judged. Although bright stimuli appearing at the bright-and-dim location were judged to be earlier, this effect was small and insignificant. Further, the intensity dissociation between RT and TOJ was insensitive to random vs blockwise presentations of intensities, therefore was not modified by attentional preferences. Thus, asymmetrical arrangement of stimuli has an impact on the allocation of attention, but only in the RT task. Therefore dissociations between TOJ and response times cannot be accounted for by an attentional bias in the TOJ task but probably by different use of temporal information in the two tasks.
如果两个刺激需要不同的时间来处理，原则上这种差异应在反应时间（RT）和对其时间顺序的判断（TOJ）中都得到体现。然而，已有报道称RT和TOJ之间存在几种分离现象，例如，当刺激强度降低时，RT比TOJ受到的影响更大。对这些分离现象的一种解释是假设两项任务所引发的注意力分配存在差异。为了验证这一假设，在本研究中，在两个刺激位置（注视点上方和下方）之间诱导出不同的注意力分布。只有明亮刺激出现在一个位置，而另一个位置既有明亮刺激也有暗淡刺激。在两项RT实验中，参与者必须对出现在两个位置之一的每个刺激做出反应。当明亮刺激出现在可能出现暗淡刺激的位置时，对其的反应时间更快。这一发现表明，注意力分配适应了刺激的不对称排列，而非明确指令所暗示的那样。在两项TOJ实验中，必须判断出现在两个位置的刺激的时间顺序。尽管出现在明暗位置的明亮刺激被判断为更早出现，但这种效应很小且不显著。此外，RT和TOJ之间的强度分离对强度的随机呈现与分块呈现不敏感，因此不会因注意力偏好而改变。因此，刺激的不对称排列对注意力分配有影响，但仅在RT任务中如此。所以，TOJ和反应时间之间的分离不能用TOJ任务中的注意力偏差来解释，而可能是由于两项任务中对时间信息的不同运用。
