Department of Neuroimaging, King’s College London, UK.
J Pers Soc Psychol. 2012 May;102(5):910-24. doi: 10.1037/a0026825. Epub 2012 Jan 9.
Anxiety and fear are often confounded in discussions of human emotions. However, studies of rodent defensive reactions under naturalistic conditions suggest anxiety is functionally distinct from fear. Unambiguous threats, such as predators, elicit flight from rodents (if an escape-route is available), whereas ambiguous threats (e.g., the odor of a predator) elicit risk assessment behavior, which is associated with anxiety as it is preferentially modulated by anti-anxiety drugs. However, without human evidence, it would be premature to assume that rodent-based psychological models are valid for humans. We tested the human validity of the risk assessment explanation for anxiety by presenting 8 volunteers with emotive scenarios and asking them to pose facial expressions. Photographs and videos of these expressions were shown to 40 participants who matched them to the scenarios and labeled each expression. Scenarios describing ambiguous threats were preferentially matched to the facial expression posed in response to the same scenario type. This expression consisted of two plausible environmental-scanning behaviors (eye darts and head swivels) and was labeled as anxiety, not fear. The facial expression elicited by unambiguous threat scenarios was labeled as fear. The emotion labels generated were then presented to another 18 participants who matched them back to photographs of the facial expressions. This back-matching of labels to faces also linked anxiety to the environmental-scanning face rather than fear face. Results therefore suggest that anxiety produces a distinct facial expression and that it has adaptive value in situations that are ambiguously threatening, supporting a functional, risk-assessing explanation for human anxiety.
焦虑和恐惧在人类情感的讨论中经常被混淆。然而，对啮齿动物在自然条件下防御反应的研究表明，焦虑在功能上与恐惧不同。明确的威胁，如捕食者，会促使啮齿动物逃跑（如果有逃生路线的话），而模糊的威胁（例如，捕食者的气味）会引发风险评估行为，这与焦虑有关，因为它优先被抗焦虑药物调节。然而，如果没有人类的证据，就假设基于啮齿动物的心理模型对人类有效还为时过早。我们通过向 8 名志愿者展示情感场景并要求他们摆出面部表情，来测试风险评估对焦虑的人类有效性解释。然后，将这些表情的照片和视频展示给 40 名参与者，让他们将这些表情与场景匹配并为每个表情贴上标签。描述模糊威胁的场景更倾向于与对同一场景类型做出反应的面部表情相匹配。这种表情由两种合理的环境扫描行为（眼球转动和头部转动）组成，被标记为焦虑，而不是恐惧。描述明确威胁的场景所引发的表情被标记为恐惧。然后，将生成的情绪标签呈现给另外 18 名参与者，让他们将这些标签与面部表情的照片匹配。这种将标签与面部表情的反向匹配也将焦虑与环境扫描表情联系起来，而不是与恐惧表情联系起来。因此，结果表明焦虑会产生一种独特的面部表情，并且在模糊威胁的情况下具有适应性价值，支持了一种用于人类焦虑的功能性、风险评估解释。
