More invasive and impressive therapeutic rituals are generally believed to be more powerful interventions than less impressive ones. This chapter reviews and discusses evidence from randomized clinical trials and meta-analyses for such a differential effectiveness of placebo interventions. Evidence from clinical research that different types of placebo are regularly associated with different magnitudes of placebo effect is limited. However, one area where hints from a variety of sources are accumulating is sham acupuncture in the treatment of pain. Furthermore, there is preliminary evidence that sham surgery and ambiguous evidence that sham injections are associated with enhanced placebo effects on pain. Among the factors that may account for a greater effectiveness of such treatment procedures are the lively perceptual context of the procedures themselves, the attention and enhanced emotional support by healthcare providers, and the increased expectation and motivation of patients. A differential effectiveness of placebo control procedures in clinical trials would have important implications for clinical research.

Management of pain is an essential responsibility in medicine. With the advance of surgical technologies, the use of interventional and other invasive methods to treat pain has become prominent and growing in use. Yet, rarely are these techniques evaluated in a way that can separate their specific impact on pain from expectation and context effects that these rituals share with many other less invasive approaches to pain. In this chapter we examine invasive studies for pain that are compared to sham procedures that mimic the procedure without delivering actual surgery. We describe studies for angina, low back pain, osteoarthritis, and headache, examining quality and outcomes. Remarkably, when compared to a sham group, most invasive procedures do not produce a significant effect on pain. We explore clinical and ethical implications of these data and recommend that more rigorous research be done on invasive procedures before they are adopted for widespread use.

Studies of placebo analgesia necessarily involve the induction and reporting of pain. The pain report is the basic dependent variable in many studies of placebo analgesia, and reported pain should ideally reflect the pain experience. However, the pain report is subject to a number of different influences that threaten the internal validity of research on pain and, consequently, placebo analgesia. The study of placebo analgesia introduces several other issues, in terms of the design of studies that researchers must deal with. Many methodologic issues have been solved, but some important issues are still unresolved. The concept of expectation is central to studies of placebo effects, and poses special challenges in terms of its conceptual status and its measurement.

From Pavlov's dog expecting food when hearing a bell to stereotypes as expectations about other people’s behaviour, from Bandura’s self-efficacy as expectation for success and failure of one’s own behaviour to the "predictive brain" concept in current perception theories: expectations have been a central construct in different areas of psychological research. In each of these areas, specific concepts, theoretical approaches, and empirical methods have been developed to explain when and why expectations persist and when they do not. Many theories assume that expectations are likely to change in the face of disconfirming evidence. However, sometimes expectations persist even though they are empirically violated, suggesting that they can be “sticky” under certain circumstances. But what are these circumstances? And what are the psychological mechanisms that can explain why and when expectations persist or change after being confronted with expectation-violating evidence? Each contribution of the current book offers insights into individuals’ reactions to violations of expectations. They show that many pieces of the puzzle have been collected in the many sub-displiclines of psychology and that putting them together in an integrative fashion stays a fascinating enterprise.

Abstract: Objective. There is mounting evidence that more elaborate treatment rituals trigger larger nonspecific effects. The reasons for this remain unclear. In a pilot field study, we investigated the role of psychophysiological changes during a touch-based healing ritual for improvements in subjective well-being. Methods. Heart rate, respiratory rate, and skin conductance levels (SCL) were continuously assessed in 22 subjects before, during, and after a touch-based healing ritual. Participants rated their expectations and subjective well-being was assessed before and after the ritual by the "Short Questionnaire on Current Disposition". Results. Subjective well-being increased significantly from before to after the ritual. The analysis of psychophysiological changes revealed a significant increase in respiratory rate from baseline to ritual, while skin conductance, heart rate, and heart rate variability did not change. Increases in SCL as well as decreases in respiratory rate from baseline to ritual were significantly associated with improvements in subjective well-being. Regression analyses showed increases in SCL to be the only significant predictor of improvements in well-being. Conclusion. Higher sympathetic arousal during a touch-based healing ritual predicted improvements in subjective well-being. Results suggest the occurrence of an anticipatory stress response, that is, a state of enhanced sympathetic activity that is known to precede relaxation