Koivisto Mika, Grassini Simone
Department of Psychology, University of Turku, Turku, Finland.
PLoS One. 2018 Feb 5;13(2):e0192201. doi: 10.1371/journal.pone.0192201. eCollection 2018.
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.
连续闪光抑制（CFS）已成为研究无意识加工的一种常用工具，但在CFS条件下视觉刺激的无意识加工发生的水平尚不清楚。反应启动是一种强大且被充分理解的现象，即如果启动刺激和目标刺激与相同的反应相关联，启动刺激会促进对目标的明显反应。我们使用CFS来研究形状的无意识反应启动：向左或向右定向的箭头作为启动刺激和目标刺激。启动刺激在意识阈限附近呈现，每次试验后会以平衡顺序进行关于启动刺激可见性的主观评分以及关于启动刺激方向的强制选择反应。在没有任何关于启动刺激存在的报告意识的试验中，对启动刺激方向的辨别处于随机水平。然而，在这种无意识试验中会引发启动效应。无意识启动不受启动刺激 - 目标刺激起始异步性（SOA）/启动刺激持续时间的影响，而有意识加工，如通过启动刺激方向辨别能力增强和有意识启动所表明的，在最长的SOA/启动刺激持续时间时增加。这些结果表明，有意识和无意识过程可以通过CFS分离，并且CFS掩蔽不会完全抑制形状的无意识视觉加工。
