Świder Karolina, Bąbel Przemysław
Jagiellonian University, Institute of Psychology, Kraków, Poland.
PLoS One. 2016 Jun 30;11(6):e0158363. doi: 10.1371/journal.pone.0158363. eCollection 2016.
Research shows that placebo analgesia and nocebo hyperalgesia can be induced through observational learning. Our aim was to replicate and extend these results by studying the influence of the type and colour of stimuli used as placebos on the placebo effects induced by observational learning. Three experimental and two control groups were tested. All participants received pain stimuli of the same intensity preceded by colour lights (green and red) or geometric shapes (circles and squares). Before receiving pain stimuli, participants in the experimental groups, but not in the control groups, observed a model who rated pain stimuli that were preceded by either green lights (green placebo group), red lights (red placebo group), or circles (circle placebo group) as being less painful than those preceded by either red lights (green placebo group), green lights (red placebo group), or squares (circle placebo group). As a result participants in the experimental groups rated pain stimuli preceded by either green lights (green placebo group), red lights (red placebo group), or circles (circle placebo group) as being less painful than the participants in the control groups did, indicating that placebo effect was induced. No statistically significant differences were found in the magnitudes of the placebo effects between the three experimental groups (green placebo, red placebo, and circle placebo groups), indicating that neither the type nor the colour of placebo stimuli affected the placebo effects induced by observational learning. The placebo effects induced by observational learning were found to be unrelated to the individual differences in pain anxiety, fear of pain, and empathy.
研究表明，通过观察学习可以诱发安慰剂镇痛和反安慰剂痛觉过敏。我们的目的是通过研究用作安慰剂的刺激类型和颜色对观察学习诱发的安慰剂效应的影响，来复制和扩展这些结果。对三个实验组和两个对照组进行了测试。所有参与者在接受相同强度的疼痛刺激之前都会先看到彩色灯光（绿色和红色）或几何形状（圆形和方形）。在接受疼痛刺激之前，实验组的参与者（而非对照组的参与者）观察了一个模型，该模型将在绿色灯光（绿色安慰剂组）、红色灯光（红色安慰剂组）或圆形（圆形安慰剂组）之前出现的疼痛刺激评为比在红色灯光（绿色安慰剂组）、绿色灯光（红色安慰剂组）或方形（圆形安慰剂组）之前出现的疼痛刺激疼痛感更轻。结果，实验组中在绿色灯光（绿色安慰剂组）、红色灯光（红色安慰剂组）或圆形（圆形安慰剂组）之前接受疼痛刺激的参与者比对照组的参与者将疼痛刺激评为疼痛感更轻，这表明诱发了安慰剂效应。在三个实验组（绿色安慰剂组、红色安慰剂组和圆形安慰剂组）之间，未发现安慰剂效应的大小存在统计学上的显著差异，这表明安慰剂刺激的类型和颜色均未影响观察学习诱发的安慰剂效应。研究发现，观察学习诱发的安慰剂效应与疼痛焦虑、对疼痛的恐惧和同理心方面的个体差异无关。
