From the late 1950s, the so-called cognitive revolution became prominent among psychologists. Following this trend, Stanley Schachter and Jerome Singer proposed that there are cognitive factors that influence the varied states of emotions, moods and feelings. They took account of the physiological-based theories such as the James-Lange Theory and the Cannon-Bard Theory, and came with a conclusion that the various visceral or physiological patterns do not match the wide variety of emotional states of individuals. The theory was formally introduced by Schachter and Singer in 1962.
The framework above shows the sequence from the stimulating event to the emergence of emotions. When an individual encounters a stimulating event, perception and interpretation of the stimulus follows. After perception and interpretation of the sensory information, the processed information is divided into two: stimulus and the context of the event, which is a specific cognitive label. The information about the stimulus triggers a general autonomic arousal. In addition to the general autonomic arousal, the cognitive label causes a particular emotion to be experienced. Once an emotion is experienced, feedback occurs.
In 1962, Schachter and Singer conducted a study to test their theory. The research included 184 male college students as participants who were told that a vitamin compound called Suproxin would be injected to them. However, the injection was not Suproxin; rather, it is composed of either 0.5 mL of epinephrine (experiment group) or 0.5 mL of saline solution as placebo (control group). Then, the researchers divided the subjects into three conditions: (1) Informed condition (participants know the potential side effects of the injection), (2) Ignorant condition (participants do not know the potential side effects), and (3) Misinformed condition (participants know of the side effects being fabricated). Then, the participants encountered paired stooges whose roles were to act in either euphoric or angry manner. The variable being manipulated was the “cognitive circumstance”. The measurement of emotions was done via two processes: semi-private index (one-way mirror assessment) and public index (Likert scale self-report).
The result of the study was that the subjects under the Ignorant condition and Misinformed condition revealed considerably and consistently higher scores on both euphoric and angry conditions as compared to participants under the Placebo condition and the Informed condition. This proved the original hypothesis of Schachter and Singer, that is, cognitive labelling (informed, ignorant or misinformed) together with general autonomic arousal (euphoric or angry) lead to the emergence of emotions.