Peters Megan A K, Lau Hakwan
Department of Psychology, University of California, Los Angeles, Los Angeles, United States.
Brain Research Institute, University of California, Los Angeles, Los Angeles, United States.
Elife. 2015 Oct 3;4:e09651. doi: 10.7554/eLife.09651.
Many believe that humans can 'perceive unconsciously' - that for weak stimuli, briefly presented and masked, above-chance discrimination is possible without awareness. Interestingly, an online survey reveals that most experts in the field recognize the lack of convincing evidence for this phenomenon, and yet they persist in this belief. Using a recently developed bias-free experimental procedure for measuring subjective introspection (confidence), we found no evidence for unconscious perception; participants' behavior matched that of a Bayesian ideal observer, even though the stimuli were visually masked. This surprising finding suggests that the thresholds for subjective awareness and objective discrimination are effectively the same: if objective task performance is above chance, there is likely conscious experience. These findings shed new light on decades-old methodological issues regarding what it takes to consider a neurobiological or behavioral effect to be 'unconscious,' and provide a platform for rigorously investigating unconscious perception in future studies.
许多人认为人类能够“无意识地感知”——对于短暂呈现并被掩盖的微弱刺激,在没有意识的情况下也有可能进行高于随机水平的辨别。有趣的是,一项在线调查显示,该领域的大多数专家都认识到缺乏关于这一现象的令人信服的证据,但他们仍然坚持这种观点。通过使用最近开发的一种无偏差实验程序来测量主观内省(信心),我们没有发现无意识感知的证据;参与者的行为与贝叶斯理想观察者的行为相符,尽管刺激是视觉上被掩盖的。这一惊人发现表明,主观意识和客观辨别的阈值实际上是相同的:如果客观任务表现高于随机水平,那么很可能存在有意识的体验。这些发现为数十年来关于将神经生物学或行为效应视为“无意识”所需条件的方法论问题提供了新的视角,并为未来研究严格调查无意识感知提供了一个平台。