Example
An example of a scenario involving these various effects is as follows: A woman goes to her doctor with a problem. The doctor diagnoses with certainty, and then clearly explains the diagnosis and the expected route towards recovery. If he does this convincingly, calming her, removing fear and instilling hope, she will likely, through the positive expectancy, experience the placebo effect, aiding in her recovery.
On the other hand, if her doctor had had little time for her, was uncertain about the diagnosis, and had given her a prescription, combined with a message along the lines of, "this may help sometimes", and added a message about possible horrible side effects (combined, say, with the patient having talked to a neighbor who also speaks along the same lines about the horrible side effects), then the chance of negative subject-expectancy, or nocebo, becomes quite large.
A placebo is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets, inert injections, sham surgery, and other procedures.
In the case of uncertainty, expectation is what is considered the most likely to happen. An expectation, which is a belief that is centered on the future, may or may not be realistic. A less advantageous result gives rise to the emotion of disappointment. If something happens that is not at all expected, it is a surprise. An expectation about the behavior or performance of another person, expressed to that person, may have the nature of a strong request, or an order; this kind of expectation is called a social norm. The degree to which something is expected to be true can be expressed using fuzzy logic. Anticipation is the emotion corresponding to expectation.
In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expectations, observer's effect on the participants, observer bias, confirmation bias, and other sources. A blind can be imposed on any participant of an experiment, including subjects, researchers, technicians, data analysts, and evaluators. In some cases, while blinding would be useful, it is impossible or unethical. For example, it is not possible to blind a patient to their treatment in a physical therapy intervention. A good clinical protocol ensures that blinding is as effective as possible within ethical and practical constraints.
The Pygmalion effect, or Rosenthal effect, is a psychological phenomenon in which high expectations lead to improved performance in a given area. The effect is named for the Greek myth of Pygmalion, the sculptor who fell so much in love with the perfectly beautiful statue he created that the statue came to life. The psychologists Robert Rosenthal and Lenore Jacobson, in their book Pygmalion in the Classroom, borrowed something of the myth by advancing the idea that teachers' expectations of their students affect the students' performance, a view that has been called into question as a result of later research findings.
Prognosis is a medical term for predicting the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen or remain stable over time; expectations of quality of life, such as the ability to carry out daily activities; the potential for complications and associated health issues; and the likelihood of survival. A prognosis is made on the basis of the normal course of the diagnosed disease, the individual's physical and mental condition, the available treatments, and additional factors. A complete prognosis includes the expected duration, function, and description of the course of the disease, such as progressive decline, intermittent crisis, or sudden, unpredictable crisis.
The observer-expectancy effect is a form of reactivity in which a researcher's cognitive bias causes them to subconsciously influence the participants of an experiment. Confirmation bias can lead to the experimenter interpreting results incorrectly because of the tendency to look for information that conforms to their hypothesis, and overlook information that argues against it. It is a significant threat to a study's internal validity, and is therefore typically controlled using a double-blind experimental design.
A nocebo effect is said to occur when negative expectations of the patient regarding a treatment cause the treatment to have a more negative effect than it otherwise would have. For example, when a patient anticipates a side effect of a medication, they can experience that effect even if the "medication" is actually an inert substance. The complementary concept, the placebo effect, is said to occur when positive expectations improve an outcome. The nocebo effect is also said to occur in someone who falls ill owing to the erroneous belief that they were exposed to a toxin i.e. SARS-CoV-2 vaccine adulterants, or to a physical phenomenon they believe is harmful, such as EM radiation.
An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. The term complication is similar to adverse effect, but the latter is typically used in pharmacological contexts, or when the negative effect is expected or common. If the negative effect results from an unsuitable or incorrect dosage or procedure, this is called a medical error and not an adverse effect. Adverse effects are sometimes referred to as "iatrogenic" because they are generated by a physician/treatment. Some adverse effects occur only when starting, increasing or discontinuing a treatment. Adverse effects can also be caused by placebo treatments . Using a drug or other medical intervention which is contraindicated may increase the risk of adverse effects. Adverse effects may cause complications of a disease or procedure and negatively affect its prognosis. They may also lead to non-compliance with a treatment regimen. Adverse effects of medical treatment resulted in 142,000 deaths in 2013 up from 94,000 deaths in 1990 globally.
A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements. Scientific controls are a part of the scientific method.
The two-factor theory of emotion states that emotion is based on two factors: physiological arousal and cognitive label. The theory was created by researchers Stanley Schachter and Jerome E. Singer. According to the theory, when an emotion is felt, a physiological arousal occurs and the person uses the immediate environment to search for emotional cues to label the physiological arousal. This can sometimes cause misinterpretations of emotions based on the body's physiological state. When the brain does not know why it feels an emotion it relies on external stimulation for cues on how to label the emotion.
In social research, particularly in psychology, the term demand characteristic refers to an experimental artifact where participants form an interpretation of the experiment's purpose and subconsciously change their behavior to fit that interpretation. Typically, demand characteristics are considered an extraneous variable, exerting an effect on behavior other than that intended by the experimenter. Pioneering research was conducted on demand characteristics by Martin Orne.
A glossary of terms used in clinical research.
Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed to have no real effect. Placebos are most commonly used in blinded trials, where subjects do not know whether they are receiving real or placebo treatment. Often, there is also a further "natural history" group that does not receive any treatment at all.
The word placebo was used in a medicinal context in the late 18th century to describe a "commonplace method or medicine" and in 1811 it was defined as "any medicine adapted more to please than to benefit the patient". Although this definition contained a derogatory implication, it did not necessarily imply that the remedy had no effect.
Irving Kirsch is an American psychologist and academic. He is the Associate Director of the Program in Placebo Studies and a lecturer in medicine at the Harvard Medical School and Beth Israel Deaconess Medical Center. He is also professor emeritus of psychology at the Universities of Hull and Plymouth in the United Kingdom, and the University of Connecticut in the United States. Kirsch is a leading researcher within the field of placebo studies who is noted for his work on placebo effects, antidepressants, expectancy, and hypnosis. He is the originator of response expectancy theory, and his analyses of clinical trials of antidepressants have influenced official treatment guidelines in the United Kingdom. He is the author of the 2009 book The Emperor's New Drugs, which argued most antidepressant medication is effective primarily due to placebo effects.
In the design of experiments, a between-group design is an experiment that has two or more groups of subjects each being tested by a different testing factor simultaneously. This design is usually used in place of, or in some cases in conjunction with, the within-subject design, which applies the same variations of conditions to each subject to observe the reactions. The simplest between-group design occurs with two groups; one is generally regarded as the treatment group, which receives the ‘special’ treatment, and the control group, which receives no variable treatment and is used as a reference The between-group design is widely used in psychological, economic, and sociological experiments, as well as in several other fields in the natural or social sciences.
The Golem effect is a psychological phenomenon in which lower expectations placed upon individuals either by supervisors or the individual themselves lead to poorer performance by the individual. This effect is mostly seen and studied in educational and organizational environments. It is a form of self-fulfilling prophecy.
Fabrizio Benedetti is professor of physiology and neuroscience at the University of Turin Medical School in Turin, Italy and a researcher in the field of placebo studies. He is known for his research into the placebo and nocebo effects.
Placebo analgesia occurs when the administration of placebos leads to pain relief. Because placebos by definition lack active ingredients, the effect of placebo analgesia is considered to result from the patient's belief that they are receiving an analgesic drug or other medical intervention. It has been shown that, in some cases, the endogenous opioid system is critical for mediating placebo analgesia, as evidenced by the ability of such analgesia to be reduced by the opioid antagonist naloxone. However, it is also possible for placebo analgesia to be mediated by non-opioid mechanisms, in which case it would not be affected by naloxone. Other research has indicated that the human spinal cord, prefrontal cortex, and rostral anterior cingulate cortex also play a role in placebo analgesia.
Alia Joy Crum is an American psychologist who is the principal investigator of the Stanford Mind and Body Lab.
