Background and objectives

People high in trait anxiety or depression overestimate the probability of negative events, and underestimate the probability of positive events, relative to people low in trait anxiety and depression. Although this probability bias may be fundamental to some emotional disorders, its causes are not well understood. The dominant explanations are based on the availability heuristic: people relatively high in anxiety or depression find it relatively easy to imagine reasons why bad things might happen to them, and this affects their probability estimates. We tested, for the first time, whether individual differences in the availability of such reasons mediate the relationships between trait anxiety or depression and probability bias, in a nonclinical sample.

Methods

Two hundred and seventy-eight undergraduates generated reasons why a set of positive and negative events might vs. might not happen to them, before rating those events’ probability and potential impact on their lives.

Results

Individual differences in the availability of reasons why good and bad events might vs. might not happen did not mediate the sizeable relationships between trait anxiety and probability bias, and between trait depression and probability bias; these relationships remained significant when availability was controlled. Results for the impact of events (‘cost bias’) were less clear.

Limitations

Replication with patient groups would be invaluable; different operationalisations of availability may change the results.

Conclusions

Availability can influence probability estimates, but it does not explain why we see probability bias in people with high trait anxiety or depression.

中文翻译：

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特质焦虑和特质抑郁的偏差概率估计与偏差可用性无关

背景和目标

相对于特质焦虑和抑郁程度较低的人，特质焦虑或抑郁程度高的人会高估负面事件发生的概率，而低估积极事件发生的概率。尽管这种概率偏差可能是某些情绪障碍的基础，但其原因尚不清楚。主要的解释是基于可用性启发法：焦虑或抑郁程度相对较高的人发现相对容易想象坏事可能发生在他们身上的原因，这会影响他们的概率估计。我们第一次在非临床样本中测试了此类原因可用性的个体差异是否介导了特质焦虑或抑郁与概率偏差之间的关系。

方法

278 名本科生在对这些事件的概率和对他们生活的潜在影响进行评级之前，提出了为什么一系列正面和负面事件可能发生在他们身上的原因。

结果

好的和坏的事件可能发生和可能不会发生的原因的可用性的个体差异并没有调节特质焦虑和概率偏差之间以及特质抑郁和概率偏差之间的相当大的关系；当可用性受到控制时，这些关系仍然很重要。事件影响的结果（“成本偏差”）不太清楚。

限制

与患者组的复制将是无价的；可用性的不同操作可能会改变结果。

结论

可用性会影响概率估计，但它并不能解释为什么我们在具有高特质焦虑或抑郁的人身上看到概率偏差。