Unconscious response priming during continuous flash suppression

Continuous flash suppression (CFS) has become a popular tool for studying unconscious processing, but the level at which unconscious processing of visual stimuli occurs under CFS is not clear. Response priming is a robust and well-understood phenomenon, in which the prime stimulus facilitates overt responses to targets if the prime and target are associated with the same response. We used CFS to study unconscious response priming of shape: arrows with left or right orientation served as primes and targets. The prime was presented near the limen of consciousness and each trial was followed by subjective rating of visibility and a forced-choice response concerning the orientation of the prime in counterbalanced order. In trials without any reported awareness of the presence of the prime, discrimination of the prime’s orientation was at chance level. However, priming was elicited in such unconscious trials. Unconscious priming was not influenced by the prime-target onset-asynchrony (SOA)/prime duration, whereas conscious processing, as indicated by the enhanced discriminability of the prime’s orientation and conscious priming, increased at the longest SOAs/prime durations. These results show that conscious and unconscious processes can be dissociated with CFS and that CFS-masking does not completely suppress unconscious visual processing of shape.

连续闪烁抑制（Continuous flash suppression, CFS）现已成为研究无意识加工的常用手段，但CFS范式下视觉刺激的无意识加工发生于何种层面仍不明确。反应启动效应（response priming）是一种稳定且研究较为透彻的现象：当启动刺激与靶刺激对应相同反应时，启动刺激会促进个体对靶刺激的外显反应。本研究采用CFS范式探究形状的无意识反应启动效应：以朝向为左或右的箭头作为启动刺激与靶刺激。启动刺激呈现在意识阈限附近，每轮试次后均进行可见性主观评定与启动刺激朝向的迫选反应，二者的呈现顺序采用平衡设计。在未报告觉察到启动刺激存在的试次中，被试对启动刺激朝向的辨别力处于随机水平，但此类无意识试次中仍出现了启动效应。无意识启动效应不受启动-靶刺激呈现时间间隔（Stimulus Onset Asynchrony, SOA）/启动刺激呈现时长的影响；而以启动刺激朝向辨别力提升及有意识启动效应为指标的意识加工，则在最长的SOA/启动时长条件下有所增强。上述结果表明，借助CFS范式可分离意识与无意识加工过程，且CFS掩蔽并未完全抑制对形状的无意识视觉加工。