You Gotta Know These Psychological Experiments and Studies
- Ivan Pavlov’s classical conditioning experiments (1901) were among the first to study the ways in which unrelated unconditioned and neutral stimuli could be linked together through repetition to produce a conditioned response. Pavlov, who studied the digestive tracts of dogs (work that won him the 1904 Nobel Prize in Physiology or Medicine), noticed that his canine subjects began to salivate as soon as they saw the lab assistant who normally fed them, which he called “psychic secretion.” Pavlov designed an experiment in which dogs heard the sound of a metronome (commonly misidentified as a bell) and were then presented with food. With repetition, the neutral stimulus of the metronome became linked to the unconditioned stimulus of food and the unconditioned response of salivation to produce the conditioned response of salivating at the sound of the metronome.
- The Little Albert experiment (1920) was carried out by psychologist John Watson, with assistance from Rosalie Rayner, to test if it was possible to intentionally condition fear in an otherwise normal child. Watson initially exposed an infant test subject (identified by the pseudonym “Albert”) to numerous white, fluffy stimuli, such as a rat, a rabbit, and wool; the infant displayed no fear of these items. Watson then began to expose the infant to a white rat, while banging a bar with a hammer to create a loud, scary noise whenever the infant interacted with the rat. Eventually, Albert began to react with distress when exposed to any white fluffy stimuli, including a Santa Claus mask. The experiment has been heavily criticized on both ethical grounds (for the infliction of trauma on an infant) and on procedural grounds (as one child identified as potentially being “Little Albert” may have been born with serious cognitive impairment).
- The Skinner box (first used ca. 1930) was an apparatus developed by psychologist B. F. Skinner during his time as a graduate student at Harvard to explore the effects of operant conditioning, in which a behavior may be increased or decreased through the use of reinforcement or punishment, respectively. The design of the Skinner box is similar to the puzzle box developed earlier by Edward Thorndike. The most basic Skinner box consists of a small chamber, into which an animal is introduced, and a lever (or button, or other apparatus), which Skinner called a “manipulandum.” The manipulandum can deliver food, turn off an electrified floor, or in some other way affect the environment inside the box positively or negatively. The animal’s interaction with the lever allows researchers to observe changes in behavior in response to repeated reinforcements or punishments.
- The Clark doll experiment (1940) studied the perception of race in children. Mamie Phipps Clark and Kenneth Clark were a married team of psychologists and the first African Americans to receive doctorates in psychology at Columbia University. In a series of studies, they presented children across the country—from all races—with dolls that were identical except for skin color and hairstyle. They then asked the children to identify the “nice doll,” the “bad doll,” and other questions involving subjective judgments. The results of the study indicated that children of all races showed a preference for the white doll, indicating that racism in American society created an inherent sense of inferiority in Black children even by the age of five. The Clark’s research was cited by the Supreme Court in its decision in Brown v. Board of Education ordering the desegregation of schools.
- The first Asch conformity experiment (1951) was designed and run by Solomon Asch at Swarthmore College in an attempt to see whether individuals would conform to the thinking of a group of peers in a situation in which the group was clearly wrong. Participants in the experiment were paired with seven other people—all of whom were in on the plan. The groups were shown a “base” line, then were shown three other lines, and were asked to pick which of the three other lines was the same length as the “base” line. On pre-planned trials, the seven confederates each intentionally picked a line that was clearly a different length than the “base” line. In nearly 40 percent of these trials, the subject of the experiment also gave an incorrect answer, likely to conform with the answer provided by the others.
- The Milgram obedience experiment (1961) (often just called the “Milgram experiment”) was carried out at Yale University by psychologist Stanley Milgram. Milgram was inspired to conduct the experiment by the high-profile trial of Adolf Eichmann, who claimed the Nazis carrying out the Holocaust did it because they were merely “following orders.” In Milgram’s experiment, the subject was led to believe they were administering electric shocks to a “learner” (who was assisting in running the experiment) to punish the learner for making mistakes. Subjects were ordered to increase the voltage to dangerously high levels as the experiment continued, as the learner screamed in pain and pleaded with them to stop; if they stopped to question whether the experiment was safe, they were told to continue. Over 60 percent of participants eventually administered shocks so powerful that they would have killed the learner had they been real.
- The Bobo doll experiment (1961) was carried out by Albert Bandura at Stanford University, who wanted to study the effect of watching an adult model on the behavior of children. Children in the experiment observed an adult interacting with a “Bobo doll,” a large self-righting toy designed to look like a clown. In some cases, the adult either completely ignored the doll; in other cases, the adult was highly aggressive toward the doll, to the extent of throwing it, hitting it with a mallet, and yelling at it. Bandura found that children who observed an adult acting aggressively toward the doll were far more likely to act aggressively towards the doll themselves, as compared to children who watched a model ignoring the doll. The experiment provided support for the idea of social learning theory, which holds that behaviors may be learned by observing models.
- The original Small-World experiment (1966–1967) was carried out by Stanley Milgram (who also carried out the obedience experiment) to examine the interconnectedness of Americans. Milgram mailed a number of people in Nebraska and Kansas a package, and asked them to send it to a target in Boston. If they knew the individual in Boston, they could send it directly to the target; if they did not, they were instructed to send it to a personal acquaintance who they believed would be most likely to know the person in Boston. This process continued until the package reached the final person in Boston. The experiment showed that, of the packages that did make their way to Boston, they typically did so in five or six steps, leading to the coining of the phrase “six degrees of separation.” The experiment was an important early study of social networks.
- Martin Seligman’s learned helplessness experiments (1967) were instrumental in identifying that individuals who believe they are powerless to stop a harmful stimulus will eventually stop trying to avoid it at all. Seligman divided a number of dogs into three groups: one group which received no electric shocks, one group that received electric shocks but could stop them by pressing a lever, and one group which was led to believe they had no control over when the shocks stopped or started. Each group of dogs was then placed into a new situation where they were given shocks but presented an easy means of escape. While the first two groups of dogs each quickly escaped from the shocks, the third group—those given no control over the initial shocks—made no attempt at escape. The experiment had major implications for the understanding and treatment of clinical depression via therapy.
- The Stanford prison experiment (1971) was designed by Philip Zimbardo to study the effects of power dynamics in custodial situations. Participants—college students at Stanford University—were randomly assigned to be “guards” or “prisoners” for a two-week period; the guards were instructed to refer to the prisoners only by their number, not their name. Although the experience was designed to be structured, by the second day prisoners had begun to rebel against the guards, and guards (including one nicknamed “John Wayne”) began to implement sadistic practices designed to degrade, humiliate, and dehumanize inmates. The experiment was stopped after only six days when Christina Maslach, a psychology graduate student, raised ethical objections. Zimbardo later analyzed the experiment in a book which compared the events of the Stanford prison to the abuses at Abu Ghraib. Many aspects of the experiment and its legitimacy have been questioned or disputed by contemporary researchers and experiment participants.
This article was contributed by NAQT member Jason Thompson.