Nonconscious perception and information-processing in a visual reaction time task using a backward masking paradigm

本研究项目考察了在没有意识和运动反应的情况下，信息处理的本质。我们使用反应时间（RT）任务进行了几个实验(1)具有双刺激呈现（即前/启动和后/目标模拟）来引起元对比或后向掩蔽；(2)使用手指抬起和瞄准动作作为对命令刺激的反应。在元对比实验中，我们将soa（刺激开始异步）操作为40ms (40ms- soa)，其中前一个刺激的感觉完全被后一个刺激掩盖，或者更长的时间（阈值- soa），导致前一个刺激几乎被掩盖。结果表明，在40ms和阈值soa中，RTs和对前一刺激的意识以不同的方式改变。这表明，运动反应的信息处理可能与引起感知的信息处理同时独立发生。我们还进行了一个体感觉后向掩蔽实验，通过操纵前一刺激的强度，将刺激的感觉敏感性设置为阈值水平、阈值的1.2倍和2倍。RTs和知觉意识因刺激强度而相互独立地改变，表明了与元对比实验相同的结果。在用手指抬起和瞄准任务的实验中，我们操纵了视觉刺激的大小、亮度对比和位置。通过从瞄准任务中减去举指任务的RTs计算出的RTs差异仅作为呈现位点的函数而改变。这表明运动反应与空间感知直接相关，而不是与呈现刺激的物理性质相关。总的来说，本研究项目的这些发现表明，运动反应的信息处理并不是在感知刺激的基础上发生的，运动反应和感知意识背后的两种信息处理很可能是并行激活的。虽然我们在这些实验中测量了脑电图，但脑电图数据不能有效地解释无意识感知和运动反应。这些问题应在未来的研究项目中进一步研究。少

This research project examined the nature of information processing underlying perception without awareness and motor responses. We conducted several experiments using reaction time (RT) tasks (1) with double-stimulus presentations (i.e., a preceding/prime and the following/target simuli) to cause either metacontrast or backward-masking and (2) using finger-lift and aiming movements as responses to imperative stimuli. In the metacontrast experiment we manipulated SOAs (stimulus onset asynchrony) to be either 40ms (40ms-SOA), in which the sensation of a preceding stimulus was completely masked by the following stimulus, or much longer time (threshold-SOA) which resulted in the preceding stimulus being nearly masked. Results showed that RTs and awareness of the preceding stimuli were altered in a different way to each other for the 40ms- and threshold-SOAs. This suggests that information processing for motor responses may independently occur in parallel with information processing causin … More g awareness of perception. We also conducted a somatosensory backward-masking experiment, manipulating the intensity of preceding stimulus so as to set sensory sensitivity to stimuli at either a threshold level, 1.2 times and 2 of the threshold. RTs and the awareness of perception altered independently to each other for the stimulus intensities, indicating the same findings as those in the metacontrast experiment. In the experiment using finger-lift and aiming tasks we manipulated the size, luminance contrast, and location of visual stimuli. Differences in RTs calculated by subtracting RTs for the finger-lift from those for aiming tasks altered as a function of presentation loci alone. This suggests that motor response is directly correlated to the perception of spatial rather than physical nature of presented stimuli. Collectively, these findings of this research project suggest that information processing for motor response does not occur on the basis of the awareness of perceived stimuli and that both types of information processing underlying the production of motor response and awareness of perception may well be activated in parallel. Although we measured EEG throughout these experiments, the EEG data could not result in effective explanations of nonconscious perception and motor responses. These issues should be further examined in the future research projects. Less