Some of the most famous—and most discussed—studies ever conducted are Stanley Milgram's obedience studies.
Briefly, under the guise of a learning study, an experimenter instructed participants to administer increasingly powerful electric shocks to a learner when a mistake was made on a memory task. In reality, no shocks were delivered and the learner was really an actor. Participants were instructed to start with a 15-volt shock on the first mistake and were instructed to increase the voltage in 15-volt increments for each successive mistake. Participants could hear the actors (‘learner') vocal protests and demands to be set free through the wall that separated the participant and the actor. If the participant expressed reluctance to give a shock, the experimenter (dressed in a lab coat) would verbally prod the participant to continue. The study continued until either the participant refused to continue or the participant pressed the strongest voltage lever (450 volts) three times. Disturbingly, 65% of all participants in this original version of the study continued to administer shocks to the highest level.*
The paper below addresses two critical questions (based on a limited reproduction of Milgram's experiment) that remained unanswered: (1) the participants explanations for why they continued; and (2) how participants responded to the experimenter's prods.
(1) The research supports the notion that a sense of personal responsibility contributed to the participants' decision to continue or end the procedure. “The vast majority of participants who ended the procedure early spontaneously expressed during the experimental session a sense of personal responsibility for harming the learner. In contrast, very few participants who continued the procedure to the end indicated that they felt personally responsible for harming the learner….this higher level of concern did not translate into resisting the experimenter’s instructions.“
(2)”Two answers can be suggested from the social psychological literature. First, some researchers have argued that the use of small incremental steps contributed to the high rates of obedience in Milgram’s studies. By starting with a mild 15-volt shock and proceeding at 15-volt increments, participants were placed in a kind of ‘‘foot-in-the-door’’ situation. That is, pressing the first switch increased the chances of pressing the second switch, and so on. Researchers find that the foot-in-the-door effect can be explained in part by changes in self-perception. After completing the initial task, participants come to think of themselves as the kind of person who agrees with these kinds of tasks. In a similar way, Milgram’s obedient participants may have come to see themselves as the kind of person who presses the shock switches or who does what the experimenter says. However, the same process suggests that resisting the first prod should make it easier for participants to resist the second prod, which makes it easier to resist the next prod, and so on. Each statement of resistance allows the participant to see himself or herself as the kind of person who says no to these kinds of instructions.“
Second, “the participants’ resistance to the final prod also may have been enhanced by a reactance effect. Briefly, reactance theory posits that individuals are motivated to maintain a sense of personal freedom and that perceived efforts to reduce that freedom lead people to reassert their sense of control.“
Source: In Their Own Words: Explaining Obedience to Authority Through an Examination of Participants Comments (pdf)