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

Use of placebo interventions in primary care in Poland

Objective: The aim of the study was to investigate the behavior, beliefs and attitudes of Polish primary care physicians concerning the use of placebo interventions. Subjects and Methods: A total of 220 Polish primary care physicians (internists, specialists in family medicine and pediatricians) were asked to participate in a questionnaire survey and 171 agreed to do so. The questionnaire was a self-report of the behavior, beliefs and attitudes of physicians concerning the use of placebo interventions in clinical practice. The percentages are based on the actual number of respondents to each question. Results: Of 169 respondents, 135 (80%) declared that they used or prescribed placebo interventions, with 20/169 (12%) doing so almost every day, 51/169 (30%) once a week and 44/169 (26%) once a month. The most common placebos used were vitamins (86/135, 66%) and homeopathy (73/135, 56%). Among the participants, 114/129 (84%) reported that the placebos were effective, with only 10/129 (8%) considering them rarely effective; 75/139 (54%) of the physicians considered placebo interventions to be effective only in patients with subjective symptoms, 116/139 (73%) indicated that individual traits of patients were decisive factors in the effectiveness of placebo interventions, and 103/159 (65%) thought that the expectations of patients were of importance. A total of 128/170 (75%) respondents thought that the mechanism of placebo effects was purely psychological. Conclusion: The use and prescription of placebo interventions seemed to be very common among Polish primary care physicians studied and they generally had positive attitudes towards their use and effectiveness

Pain rewarded: hyperalgesic and allodynic effect of operant conditioning in healthy humans : protocol for a systematic review and meta-analysis

Background: "pain rewarded" is a hypothesis wherein acute pain sufferers are exposed to reinforcers and punishers from their environment that shape their behaviour, i.e. pain responses. Such a point of view has been taken for granted by many clinicians and researchers although existing evidence has not yet been systematically summarized. This planned systematic review and meta-analysis is aiming to summarize the research findings on pain modulation (hyperalgesic effect) and pain elicitation (allodynic effect) resulting from operant conditioning procedures in healthy humans. Methods: the systematic review will be performed by searching for articles indexed in PubMed database, Cochrane Register of Controlled Trials (Central), Web of Science™, ScienceDirect, Ebsco database, PsycInfo, Medline, PsycArticles and cinahl. Studies will be included if they investigate healthy humans, exposed to modulation or elicitation of a pain experience induced by operant conditioning. Studies will be screened for eligibility and risk of bias by two independent assessors. Narrative and meta-analytical syntheses are planned. Discussion: data will be pooled and analyzed qualitatively and quantitatively (if possible) in order to advance the understanding of pain mechanisms, especially the development of chronic pain. This systematic review will guide the planning of future experiments and research by summarizing important technical details of conditioning procedures in healthy humans

Memory of dental pain induced by tooth restoration

The aims of the study were to assess the memory of dental pain induced by tooth restoration and to investigate the factors that influence the memory of pain. Two dimensions of pain, i.e., pain intensity and pain unpleasantness, were measured twice: immediately after dental treatment and at 6 or 12 weeks follow up. Regardless of the length of the recall delay, mean pain was recalled accurately, but mean pain unpleasantness was underestimated. However, underestimation of pain intensity and unpleasantness at the follow-up was observed only in the subjects who reported more intense and unpleasant pain immediately after dental treatment. Moreover, those who underestimated pain intensity and/or unpleasantness had higher scores on dental anxiety and reported more state anxiety and less positive affect before dental treatmen

The effect of the type and colour of placebo stimuli on placebo effects induced by observational learning

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

Can placebo administered in the guise of caffeine reduce the misinformation effect?

Research suggests that placebo can reduce the misinformation effect. We aimed to examine for the first time whether placebo administered in the guise of caffeine can reduce the misinformation effect. One hundred and twentythree healthy volunteers were randomly assigned to four groups in a 2 Placebo (Present, Not Present) × 2 Narrative (Misleading, Correct) study design. Participants from placebo groups drank 100 ml of placebo solution. They were told that it was water mixed with caffeine which could positively influence their memory. After three minutes, they watched a short movie clip as an original event and read a narrative with misleading details or correct details as a postevent information; they then completed a 22 -item, two -alternative forced -choice questionnaire. The results reveal that the misinformation effect occurred. Although participants in the placebo with misinformation group scored better than participants who did not drink placebo and read the narrative containing misleading details, the difference was not statistically significant. Thus, it is concluded that placebo might not be enough to reduce the misinformation effect when it is administered in the guise of caffeine

„Ameryki już mam dosyć”. Wielka Wystawa Światowa w Chicago (1893) w świetle listu Walerego Brochockiego do Marii Faleńskiej

The article is an editorial study of the letter by a painter (now forgotten) Walery Brochocki to the Warsaw translator, writer and journalist, Maria Faleńska, sent from Chicago in the summer of 1893 – with a preceding editorial that outlines the situation of the letter and comments on its content in more detail. The material comes from the correspondence of Maria née Trębicki Faleńska from 1856–1895, preserved in the collection of the National Library in Warsaw (reference number 5904, item 1, 3 cards written on both sides).The letter is worth publishing primarily due to the interesting circumstances it relates to. Brochocki belonged to a three-person committee of delegates escorting selected works of Polish artists to the Great World Exhibition organized on the occasion of the 400th anniversary of the discovery of America by Christopher Columbus (World’s Columbian Exposition). Written in a snappy language, the document contains references to significant (though perhaps not first-class) figures of that time (e.g. son of Helena Modrzejewska, engineer Ralph Modjeski) and the nature of social relations at that time (especially among the Polish diaspora), and a very critical tone of comments about the city of Chicago and the organization of the exhibition itself. When confronted with other sources, it proves the author’s keen observation sense. Brochocki presents himself as a dignified “Varsovian”, a distanced guest from the Old Continent, who describes with interest, but rather unfavorably, the American reality of the late 19th century.Artykuł jest opracowaniem edytorskim listu malarza Walerego Brochockiego do warszawskiej tłumaczki, pisarki i publicystki, Marii Faleńskiej, wysłanego latem 1893 roku z Chicago – z poprzedzającym artykułem wstępnym, który zarysowuje sytuację powstania listu i szerzej komentuje jego treść. Materiał pochodzi z korespondencji Marii z Trębickich Faleńskiej z lat 1856–1895, zachowanej w zbiorach Biblioteki Narodowej w Warszawie (sygn. 5904, poz. 1, 3 karty zapisane obustronnie). Wybrany list wart jest opublikowania przede wszystkim z uwagi na interesujące okoliczności, których dotyczy. Brochocki należał bowiem do trzyosobowego komitetu delegatów eskortujących wybrane prace polskich artystów na Wielką Wystawę Światową zorganizowaną z okazji 400 rocznicy odkrycia Ameryki przez Kolumba (World’s Columbian Exposition). Napisany żywym językiem dokument zawiera wzmianki o znaczących (choć może nie pierwszorzędnych) postaciach tamtej epoki (np. syn Heleny Modrzejewskiej, inżynier Ralph Modjeski) i charakterze ówczesnych relacji towarzyskich (zwłaszcza wśród Polonii), zaś bardzo krytyczny ton uwag na temat miasta Chicago oraz organizacji samej wystawy po skonfrontowaniu z innymi źródłami dowodzi bystrego zmysłu obserwacyjnego autora. Brochocki prezentuje się tu jako pełen godności „warszawiak”, zdystansowany gość ze Starego Kontynentu, który z zaciekawieniem, choć raczej niepochlebnie, opisuje amerykańską rzeczywistość końca XIX wieku