Psychiatric University Hospital Zurich, University of Zurich, 8032 Zurich, Switzerland.
Department of Psychiatry, University of Zurich, 8032 Zurich, Switzerland.
Learn Mem. 2021 Feb 16;28(3):95-103. doi: 10.1101/lm.050997.119. Print 2021 Mar.
In an ever-changing environment, survival depends on learning which stimuli represent threat, and also on updating such associations when circumstances shift. It has been claimed that humans can acquire physiological responses to threat-associated stimuli even when they are unaware of them, but the role of awareness in updating threat contingencies remains unknown. This complex process-generating novel responses while suppressing learned ones-relies on distinct neural mechanisms from initial learning, and has only been shown with awareness. Can it occur unconsciously? Here, we present evidence that threat reversal may not require awareness. Participants underwent classical threat conditioning to visual stimuli that were suppressed from awareness. One of two images was paired with an electric shock; halfway through the experiment, contingencies were reversed and the shock was paired with the other image. Despite variations in suppression across participants, we found that physiological responses reflected changes in stimulus-threat pairings independently of stimulus awareness. These findings suggest that unconscious affective processing may be sufficiently flexible to adapt to changing circumstances.
在不断变化的环境中，生存取决于学习哪些刺激代表威胁，以及在环境变化时更新这些关联。有人声称，即使人类不知道威胁相关的刺激，也可以对其产生生理反应，但意识在更新威胁关联中的作用尚不清楚。这个复杂的过程——在抑制已学习的反应的同时产生新的反应——依赖于与初始学习不同的神经机制，而且只有在有意识的情况下才会出现。它能无意识地发生吗？在这里，我们提供的证据表明，威胁的逆转可能不需要意识。参与者接受了对视觉刺激的经典威胁条件作用，这些刺激是从意识中抑制的。两个图像中的一个与电击配对；在实验进行到一半时，条件作用发生了逆转，电击与另一个图像配对。尽管参与者的抑制程度存在差异，但我们发现生理反应反映了刺激-威胁配对的变化，而与刺激的意识无关。这些发现表明，无意识的情感处理可能具有足够的灵活性，以适应不断变化的环境。
