Department of Psychology, University of Leuven, Belgium.
J Behav Ther Exp Psychiatry. 2012 Jun;43(2):832-7. doi: 10.1016/j.jbtep.2011.11.005. Epub 2011 Dec 13.
In a blocking procedure, a single conditioned stimulus (CS) is paired with an unconditioned stimulus (US), such as electric shock, in the first stage. During the subsequent stage, the CS is presented together with a second CS and this compound is followed by the same US. Fear conditioning studies in non-human animals have demonstrated that fear responding to the added second CS typically remains low, despite its being paired with the US. Accordingly, the blocking procedure is well suited as a laboratory model for studying (deficits in) selective threat appraisal. The present study tested the relation between trait anxiety and blocking in human aversive conditioning.
Healthy participants filled in a trait anxiety questionnaire and underwent blocking treatment in the human aversive conditioning paradigm. Threat appraisal was measured through shock expectancy ratings and skin conductance.
As hypothesized, trait anxiety was positively associated with shock expectancy ratings to the blocked stimulus.
In skin conductance responding, no significant effects of stimulus type could be detected during blocking training or testing. The current study does not allow strong claims to be made regarding the theoretical process underlying the expectancy bias we observed.
The observed shock expectancy bias might be one of the mechanisms leading to non-specific fear in individuals at risk for developing anxiety disorders. A deficit in blocking, or a deficit in selective threat appraisal at the more general level, indeed results in fear becoming non-specific and disconnected from the most likely causes or predictors of danger.
在阻滞程序中，在第一阶段，单一条件刺激（CS）与非条件刺激（US）（如电击）配对。在随后的阶段中，CS 与第二个 CS 一起呈现，并且该复合 CS 随后会出现相同的 US。非人类动物的恐惧条件反射研究表明，尽管添加的第二个 CS 与 US 配对，但对其的恐惧反应通常仍然很低。因此，阻滞程序非常适合作为研究（选择性威胁评估缺陷）的实验室模型。本研究检验了特质焦虑与人类厌恶条件反射中的阻滞之间的关系。
健康参与者填写特质焦虑问卷，并在人类厌恶条件反射范式中接受阻滞治疗。通过电击预期评分和皮肤电导来测量威胁评估。
正如假设的那样，特质焦虑与对阻滞刺激的电击预期评分呈正相关。
在皮肤电导反应中，在阻滞训练或测试期间，刺激类型没有显著影响。本研究不能对我们观察到的预期偏差背后的理论过程提出强有力的主张。
观察到的电击预期偏差可能是导致有患焦虑障碍风险的个体出现非特异性恐惧的机制之一。阻滞的缺陷，或者更一般水平上的选择性威胁评估的缺陷，确实会导致恐惧变得非特异性，并且与危险的最可能原因或预测因素脱钩。
