According to the Society of Personality and Social Psychologists, social psychologists attempt to answer the same ancient questions that personality psychologists and, before them, philosophers have struggled with since Plato: How did we become who we are? And why do we think about, act toward and treat each other as we do? However, if philosophy was concerned with the nature of the good life and personality psychology with an individual's internal motivations, social psychologists explore the social aspects of human behavior and motivation, whether it is fidelity or infidelity, prejudice or generosity of soul, courage or cowardice.
Experimental social psychology attempts to answer these questions by isolating elements within a laboratory setting. According to the authors of Experiments with People, a compilations of essays about important experiments in social psychology, "[The word experiment] refers to the random assignment of … human participants -- to different groups (conditions) where these groups are treated identically except in one or a few crucial respects (the independent variable[s]). The impact of these independent variables on how participants think or act (the dependent variables) is then assessed -- did the manipulation have an effect? Experiments have a unique advantage in that they allow causal inferences (i.e., X causes Y) to be made with confidence. They also permit alternative explanations for a phenomenon to be efficiently ruled out. … Indeed, when the findings of social psychological studies come in, the pitfalls of commonsense are often shockingly exposed."
Norman Triplett is considered the founder of experimental social psychology. In 1897–98, he published an article showing that being paced significantly increased the speed of competitive cyclists, a finding he replicated when monitoring other motor tasks. In short, how individuals act is influenced by being watched, as well as by the response of watchers to the performance. The importance of such observations to factory managers and advertisers in an industrializing economy is obvious: Profit depends upon demand for goods, yet increased production soon outstripped any rational need for material goods, especially if the material goods were well made.
However, social psychology has been used for far more important ends than manipulating people into making more, so others can consume more. Perhaps the most famous social psychology experiment of all time was Dr. Stanley Milgram's 1963 study of American obedience to orders. Milgram had initially believed that the Holocaust could be explained by cultural differences between Americans and Germans. He decided to test this hypothesis by constructing an experiment in which American men (the subjects of the experiment) would supposedly apply electrical shocks to other American men (research associates themselves) for failing to learn adequately. He believed that few of the subjects would apply the electrical shocks, and of those who did, few would apply intense shocks. Milgram's hypothesis was profoundly wrong: In his initial experiment, not one participant stopped administering electric shocks before reaching 300 volts, and nearly two-thirds administered what they believed were extreme shocks.
Out of Milgram's disturbing results grew a great many experiments into social psychology that were concerned not only with willing submission to abusive authority, but also hidden prejudices and stereotypes about men and women, race and religion. Other social psychology experiments have investigated how and the degree to which our beliefs influence our perceptions of objective reality or how our perceptions of another person's ability are influenced by that individual's appearance. (These experiments typically control for pervasive social prejudices about race and sex). In addition, more social psychology experiments have studied whom people are more likely to help when they are alone with someone in distress than when more bystanders are present at the scene.
The Society of Experimental Social Psychology publishes The Journal of Experimental Social Psychiatry, which covers a wide variety of subjects of interest to experimental social psychology, from the effect of color (specifically red or blue) on behavior to the impact of testosterone on subjects engaged in negotiations and retaliation. However, the journal tends to focus on issues involving some aspect of human inequality. Examples include studies showing increasing Caucasian-American support for social equality when that equality is presented as a moral ideal to live up to rather than an owed obligation, stressing women's appearances literally dehumanizes them and the male tendency to overestimate social support for aggression.