Lee Daryl Y H, Berry Christopher J, Shanks David R
Department of Experimental Psychology, University College London, 26 Bedford Way, London, WC1H 0AP, UK.
School of Psychology, University of Plymouth, Plymouth, UK.
Psychon Bull Rev. 2025 Apr;32(2):614-635. doi: 10.3758/s13423-024-02578-1. Epub 2024 Oct 15.
A widely adopted approach in research on unconscious perception and cognition involves contrasting behavioral or neural responses to stimuli that have been presented to participants (e.g., old items in a memory test) against those that have not (e.g., new items), and which participants do not discriminate in their conscious reports. We demonstrate that such contrasts do not license inferences about unconscious processing, for two reasons. One is Kelley's Paradox, a statistical phenomenon caused by regression to the mean. In the inevitable presence of measurement error, true awareness of the contrasted stimuli is not equal. The second is a consequence, within the framework of Signal Detection Theory, of unequal skewness in the strengths of target and nontarget items. The fallacious reasoning that underlies the employment of this contrast methodology is illustrated through both computational simulations and formal analysis, and its prevalence is documented in a narrative literature review. Additionally, a recognition memory experiment is reported which tests and confirms a prediction of our analysis of the contrast methodology and corroborates the susceptibility of this method to artifacts attributable to Kelley's Paradox and strength skewness. This work challenges the validity of conclusions drawn from this popular analytic approach.
在无意识感知与认知研究中，一种广泛采用的方法是将参与者对已呈现刺激（例如记忆测试中的旧项目）的行为或神经反应与未呈现刺激（例如新项目）的反应进行对比，而参与者在有意识报告中无法区分这些刺激。我们证明，出于两个原因，这种对比无法支持关于无意识加工的推断。一是凯利悖论，这是一种由均值回归引起的统计现象。在不可避免存在测量误差的情况下，被对比刺激的真实意识并不相等。二是在信号检测理论框架内，目标项目和非目标项目强度的偏度不均所导致的结果。通过计算模拟和形式分析说明了这种对比方法背后的错误推理，并在一篇叙述性文献综述中记录了其普遍性。此外，还报告了一项识别记忆实验，该实验测试并证实了我们对对比方法分析的一个预测，并证实了该方法易受归因于凯利悖论和强度偏度的假象影响。这项工作对从这种流行分析方法得出的结论的有效性提出了挑战。
