How does observational learning produce placebo effects? : a model integrating research findings

There is a growing body of evidence proving that observational learning, in addition to classical conditioning and verbal suggestions, may induce both placebo analgesia and nocebo hyperalgesia. However, much less is known about the mechanisms and factors influencing placebo effects induced by observational learning. The paper critically reviews the research findings in the field in the context of Bandura’s social learning theory. We apply Bandura’s taxonomy of the sources of social learning (behavioral, symbolic, and verbal modeling) and discuss the results of previous studies. Critical points in the placebo effects induced by observational learning are identified.We discuss aspects of behavior presented by the model (both verbal and nonverbal) involved in the formation of placebo effects induced by observational learning as well as the role of expectancies in this process. As a result, we propose a model that integrates the existing research findings. The model shows the main ways of transmission of painrelated information from the model to the observer. It highlights the role of expectancies and the individual characteristics of the observer in formation of placebo analgesia and nocebo hyperalgesia induced by observational learning. Finally, we propose future research directions based on our model

From past pain to future pain through the pain of others : information about other people's pain ratings can alleviate our subsequent pain

Background: Previous studies have shown that pain memories have a profound impact on subsequent pain experiences. This study investigated whether pain ratings derived from other people can modify an individual's memory of past pain. This study also examined whether pain memory modified by others' pain ratings determines subsequent pain experiences. Methods: Participants were divided into two groups: an experimental group and a control group. Participants in both groups were exposed to pain stimulation; then, they recalled its intensity twice over a period of time; after a break, they were again exposed to pain stimulation of the same intensity. The final sample consisted of 53 participants. The only difference between the experimental group and the control group was that in the former the pain ratings of other alleged participants were presented between the two consecutive pain recalls. These ratings suggested that other people experienced the same pain as less intense. Results: The pain ratings derived from other people did not alter the pain memory; nevertheless, they affected an individual's next pain experience even for a certain period of time after their presentation. This type of pain- related information shaped participants' subsequent pain experiences regardless of their empathy, conformity, and susceptibility to social influence. Conclusions: Information on pain derived from other people not only shapes the response to a novel stimulation but also substantially modifies the subsequent experience of that stimulation. Significance: The study demonstrates the importance of social information on pain and provides evidence that this type of information substantially modifies the subsequent experience of the same pain. These results suggest that social in-formation on pain can be used to alleviate pain associated with recurring medical procedures and thus increase patients' willingness to continue treatment

Nocebo hyperalgesia can be induced by classical conditioning without involvement of expectancy

Influential theoretical accounts take the position that classical conditioning can induce placebo effects through conscious expectancies. In the current study two different conditioning procedures (hidden and open) were used to separate expectancy from conditioning in order to reveal the role of expectancy in the formation of nocebo hyperalgesia. Eighty-seven healthy females were randomly assigned to three groups (hidden conditioning, open conditioning, and control). Participants were selected according to the Fear of Pain Questionnaire scores and assigned to two subgroups: high and low level of fear of pain (trait). They received electrocutaneous pain stimuli preceded by either an orange or blue color. During the conditioning phase, one color was paired with pain stimuli of moderate intensity (control stimuli) and the other color was paired with pain stimuli of high intensity (nocebo stimuli) in both hidden and open conditioning groups. Only participants in the open conditioning group were informed about this association, however just before the testing phase the expectancy of hyperalgesia induced in this way was withdrawn. In the control group, both colors were followed by control pain stimuli. During the testing phase all participants received a series of stimuli of the same intensity, regardless of the preceding color. Participants rated pain intensity, expectancy of pain intensity and fear (state). We found that nocebo hyperalgesia was induced by hidden rather than open conditioning. The hidden conditioning procedure did not produce conscious expectancies related to pain. Nocebo hyperalgesia was induced in participants with low and high fear of pain and there was no difference in the magnitude of the nocebo effect between both groups. Nocebo hyperalgesia was not predicted by the fear of upcoming painful stimuli

Acquisition of emotional responses : reconstruction and revision of the Little Albert

In 1920 John B. Watson and Rosalie Rayner published the results of the study experiment describing how they had conditioned an 11-month-old boy (known as Little Albert) to fear a rat. The experiment is one of the best known and the most frequently cited empirical studies in the history of psychology. Many studies and theories suggesting the role of learning processes in the development of emotional responses were initiated by the Little Albert experiment. The article summarizes the procedures and results of the experiment reported by J.B. Watson and R. Rayner. The importance and impact of the results of the experiment on the development of psychological theories and research is discussed. Errors in the discussions of the Little Albert experiment in Polish psychological literature are identifi ed. The results of the latest historical research on the Little Albert experiment are summarized and their consequences are discussed

Classical conditioning without verbal suggestions elicits placebo analgesia and nocebo hyperalgesia

The aim of this study was to examine the relationships among classical conditioning, expectancy, and fear in placebo analgesia and nocebo hyperalgesia. A total of 42 healthy volunteers were randomly assigned to three groups: placebo, nocebo, and control. They received 96 electrical stimuli, preceded by either orange or blue lights. A hidden conditioning procedure, in which participants were not informed about the meaning of coloured lights, was performed in the placebo and nocebo groups. Light of one colour was paired with pain stimuli of moderate intensity (control stimuli), and light of the other colour was paired with either nonpainful stimuli (in the placebo group) or painful stimuli of high intensity (in the nocebo group). In the control group, both colour lights were followed by control stimuli of moderate intensity without any conditioning procedure. Participants rated pain intensity, expectancy of pain intensity, and fear. In the testing phase, when both of the coloured lights were followed by identical moderate pain stimuli, we found a significant analgesic effect in the placebo group, and a significant hyperalgesic effect in the nocebo group. Neither expectancy nor fear ratings predicted placebo analgesia or nocebo hyperalgesia. It appears that a hidden conditioning procedure, without any explicit verbal suggestions, elicits placebo and nocebo effects, however we found no evidence that these effects are predicted by either expectancy or fear. These results suggest that classical conditioning may be a distinct mechanism for placebo and nocebo effects

Nabywanie reakcji emocjonalnych: rekonstrukcja i rewizja eksperymentu z udziałem Małego Alberta

In 1920 John B. Watson and Rosalie Rayner published the results of the study experiment describing how they had conditioned an 11-month-old boy (known as Little Albert) to fear a rat. The experiment is one of the best known and the most frequently cited empirical studies in  the history of psychology. Many studies and theories suggesting the role of learning processes in the development of emotional responses were initiated by the Little Albert experiment.  The article summarizes the procedures and results of the experiment reported by J.B. Watson and R. Rayner. The importance and impact of the results of the experiment on the development of psychological theories and research is discussed. Errors in the discussions of the Little Albert experiment in Polish psychological literature are identifi ed. The results of the latest historical research on the Little Albert experiment are summarized and their consequences are discussed

Memory of pain in adults : a protocol for systematic review and meta-analysis

Background: the way pain is remembered and reported can affect medical decisions taken by patients and health-care professionals. Memory of pain has been investigated extensively for the past few decades; however, the results of previous studies are highly variable, indicating that the recollection of pain can be accurate, overestimated or underestimated. It is therefore difficult to conclude how well pain is remembered. The aim of this systematic review and meta-analysis is to summarize research findings on memory of pain in healthy adults and patients suffering from acute and chronic pain. Methods: the systematic review will be performed by searching for articles indexed in the following databases: PubMed, MEDLINE, PsycINFO, Web of Science, ScienceDirect, PsycARTICLES, Scopus and Academic Search Complete. Studies will be included if (1) they investigated healthy adults or patients with any acute or chronic pain condition and if (2) they assessed experienced pain (pain intensity and/or pain unpleasantness) and its recollection. No restrictions related to the date of publication and recall delay will be applied. Studies will be screened for eligibility and risk of bias by two independent assessors. The risk of bias will be assessed by a modified Downs and Black checklist. A narrative synthesis will be performed in the first stage; in the second stage, the results of studies with comparable designs will be pooled in meta-analytical syntheses. Discussion: the question of whether pain is remembered accurately is crucial for valid pain diagnosis, effective treatment and prognosis. So far, a number of studies on memory of pain have been conducted; however, a definitive conclusion on whether memory of pain is accurate is still lacking. In this systematic review and meta-analysis, available data will be pooled together to further inform research and clinical practice

Placebo Groups in Research on the Effectiveness of ABA Therapeutic Techniques

Behavior analysts have shown that a single-subject experimental design (SSED) is a useful tool for identifying the effectiveness of specific therapeutic techniques, whereas researchers outside applied behavior analysis (ABA) maintain that randomized placebo-controlled trials (RPCT) provide the most definite test of efficacy. In this paper the possible benefits that could result from supporting SSED studies by placebo control groups are discussed. However, the use of placebo groups in psychotherapy research arouses considerable controversy and many researchers argue against it. The main aim of this paper is to clarify theoretical and methodological problems associated with using placebo groups in psychotherapy research and to demonstrate that these problems can be solved if the assumptions on which they are based are reformulated. The article also discusses ethical issues about the use of placebo groups in research on the effectiveness of psychotherapy

Development and cross‑national investigation of a model explaining participation in WHO‑recommended and placebo behaviours to prevent COVID‑19 infection

To protect themselves from COVID-19, people follow the recommendations of the authorities, but they also resort to placebos. To stop the virus, it is important to understand the factors underlying both types of preventive behaviour. This study examined whether our model (developed based on the Health Belief Model and the Transactional Model of Stress) can explain participation in WHO-recommended and placebo actions during the pandemic. Model was tested on a sample of 3346 participants from Italy, Japan, Poland, Korea, Sweden, and the US. It was broadly supported: objective risk and cues to action showed both direct and indirect (through perceived threat) associations with preventive behaviours. Moreover, locus of control, decision balance, health anxiety and preventive coping moderated these relationships. Numerous differences were also found between countries. We conclude that beliefs about control over health and perceived benefits of actions are critical to the development of interventions to improve adherence to recommendations