The Pervasive Problem With Placebos in Psychology: Why Active Control Groups Are Not Sufficient to Rule Out Placebo Effects
The Pervasive Problem With Placebos in Psychology: Why Active Control Groups Are Not Sufficient to Rule Out Placebo Effects
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DOI：
10.1177/1745691613491271
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发表时间：
2013-07-01
影响因子：
12.6
通讯作者：
Stutts, Cassie
中科院分区：
文献类型：
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作者：
Boot, Walter R.;Simons, Daniel J.;Stutts, Cassie
为了得出关于心理干预效果的因果结论，研究人员必须将治疗条件与对照组进行比较，对照组考虑了治疗以外的因素引起的改善。使用主动控制有助于控制实验组的改善可能是由安慰剂效应引起的。尽管活性对照组上级非接触对照组，但只有当活性对照组与实验组具有相同的改善预期时，我们才能将差异性改善归因于治疗效力。尽管需要匹配治疗组和对照组之间的期望，但几乎没有心理干预措施这样做。这种对预期控制的失败不是一个小遗漏，而是一个基本的设计缺陷，可能会破坏任何因果推理。我们用视频游戏训练文献中的一个详细例子来说明这些原则，说明使用主动控制组并不能消除期望差异。这个问题也渗透到其他干预措施中，包括那些针对心理健康，认知和教育成就的干预措施。幸运的是，测量期望值和采用替代实验设计使得控制安慰剂效应成为可能，从而增加了对心理干预的因果效力的信心。
To draw causal conclusions about the efficacy of a psychological intervention, researchers must compare the treatment condition with a control group that accounts for improvements caused by factors other than the treatment. Using an active control helps to control for the possibility that improvement by the experimental group resulted from a placebo effect. Although active control groups are superior to no-contact controls, only when the active control group has the same expectation of improvement as the experimental group can we attribute differential improvements to the potency of the treatment. Despite the need to match expectations between treatment and control groups, almost no psychological interventions do so. This failure to control for expectations is not a minor omissionit is a fundamental design flaw that potentially undermines any causal inference. We illustrate these principles with a detailed example from the video-game-training literature showing how the use of an active control group does not eliminate expectation differences. The problem permeates other interventions as well, including those targeting mental health, cognition, and educational achievement. Fortunately, measuring expectations and adopting alternative experimental designs makes it possible to control for placebo effects, thereby increasing confidence in the causal efficacy of psychological interventions.