Humans are social animals. We affect each other’s thoughts and actions, and how we do so is the topic of this chapter. This research area is called social psychology—the scientific study of how we influence one another’s behavior and thinking. To understand what is meant by such social influence, we’ll consider two real-world incidents in which social forces influenced behavior, and then, later in the chapter, we’ll return to each incident to see how social psychologists explain them.

The first incident is the brutal murder of Kitty Genovese in New York City in 1964 (briefly discussed in Chapter 1). Kitty Genovese was returning home from work late one night, when she was attacked in front of her apartment building. The attack was a prolonged one over a half-hour period in which the attacker left and came back more than once. Kitty screamed for help and struggled with the knife-wielding attacker, but no help was forthcoming. Some apartment residents saw the attack, and others heard her screams and pleas for help. Exactly how many residents witnessed the attack is not clear. Initially reported as 38 in The New York Times report, more recent analysis of the available archival evidence indicates that the number was somewhat less (Manning, Levine, & Collins, 2007). The struggle between Kitty and her attacker continued for 35 minutes before he finally fatally stabbed her. Her cries for help went unanswered. Someone finally called the police after the attacker had left, but it was too late. What social forces kept these people from acting sooner, so that Kitty Genovese’s life might have been spared? Media accounts blamed apathy created by a big-city culture (Rosenthal, 1964). Social psychological researchers, however, provide a very different explanation. We will describe this explanation in the section on social influence, when we discuss bystander intervention.

Kitty Genovese

The New York Times Photo Archives/Redux

The second incident occurred in 1978, when over 900 people who were members of Reverend Jim Jones’s Peoples Temple religious cult in Jonestown, Guyana (South America), committed mass suicide by drinking cyanide-laced Kool-Aid (though some sources say it was Flavor-Aid, a drink mix similar to Kool-Aid). These were Americans who had moved with Jones from San Francisco to Jonestown in 1977. Jonestown parents not only drank the poisoned Kool-Aid, but they also gave it to their infant children to drink. Strangely, the mass suicide occurred in a fairly orderly fashion as one person after another drank the poison. Hundreds of people went into convulsions and died within minutes. What social forces made so few of these people willing to disobey Reverend Jones’s command for this unified act of mass suicide? We will return to this question in the social influence section, when we discuss obedience.

What if you had been one of those people who witnessed Kitty Genovese’s murder? Would you have intervened or called the police? If you are like most people, you probably think that you would have done so. However, none of the witnesses to the attack did so until it was too late. Similarly, most people would probably say that they would not have drunk the poison at Jonestown. However, the vast majority did so. Why is there this discrepancy between what we say we would do and what we actually do? Social psychologists would say that when we just think about what our behavior would be in such a situation, we are not subject to the social forces that are operating in the actual situation. If you’re in the situation, however, social forces are operating and may guide your behavior in a different way. In summary, situational social forces greatly influence our behavior and thinking. Keep this in mind as we discuss various types of social influence and social thinking.