The field of social psychology is growing rapidly and is having an increasingly important influence on how we think about human behavior. Newspapers, magazines, websites, and other media frequently report the findings of social psychologists, and the results of social psychological research are influencing decisions in a wide variety of areas. Let’s begin with a short history of the field of social psychology and then turn to a review of the basic principles of the science of social psychology.

The History of Social Psychology

The science of social psychology began when scientists first started to systematically and formally measure the thoughts, feelings, and behaviors of human beings (Kruglanski & Stroebe, 2011). The earliest social psychology experiments on group behavior were conducted before 1900 (Triplett, 1898), and the first social psychology textbooks were published in 1908 (McDougall, 1908/2003; Ross, 1908/1974). During the 1940s and 1950s, the social psychologists Kurt Lewin and Leon Festinger refined the experimental approach to studying behavior, creating social psychology as a rigorous scientific discipline. Lewin is sometimes known as “the father of social psychology” because he initially developed many of the important ideas of the discipline, including a focus on the dynamic interactions among people. In 1954, Festinger edited an influential book called Research Methods in the Behavioral Sciences, in which he and other social psychologists stressed the need to measure variables and to use laboratory experiments to systematically test research hypotheses about social behavior. He also noted that it might be necessary in these experiments to deceive the participants about the true nature of the research.

Social psychology was energized by researchers who attempted to understand how the German dictator Adolf Hitler could have produced such extreme obedience and horrendous behaviors in his followers during the World War II. The studies on conformity conducted by Muzafir Sherif (1936) and Solomon Asch (1952), as well as those on obedience by Stanley Milgram (1974), showed the importance of conformity pressures in social groups and how people in authority could create obedience, even to the extent of leading people to cause severe harm to others. Philip Zimbardo, in his well-known “prison study” (Haney, Banks, & Zimbardo, 1973), found that the interactions of male college students who were recruited to play the roles of guards and prisoners in a simulated prison became so violent that the study had to be terminated early.

Social psychology quickly expanded to study other topics. John Darley and Bibb Latané (1968) developed a model that helped explain when people do and do not help others in need, and Leonard Berkowitz (1974) pioneered the study of human aggression. Meanwhile, other social psychologists, including Irving Janis (1972), focused on group behavior, studying why intelligent people sometimes made decisions that led to disastrous results when they worked together. Still other social psychologists, including Gordon Allport and Muzafir Sherif, focused on intergroup relations, with the goal of understanding and potentially reducing the occurrence of stereotyping, prejudice, and discrimination. Social psychologists gave their opinions in the 1954 Brown v. Board of Education U.S. Supreme Court case that helped end racial segregation in American public schools, and social psychologists still frequently serve as expert witnesses on these and other topics (Fiske, Bersoff, Borgida, Deaux, & Heilman, 1991). In recent years insights from social psychology have even been used to design anti-violence programs in societies that have experienced genocide (Staub, Pearlman, & Bilali, 2010).

The latter part of the 20th century saw an expansion of social psychology into the field of attitudes, with a particular emphasis on cognitive processes. During this time, social psychologists developed the first formal models of persuasion, with the goal of understanding how advertisers and other people could present their messages to make them most effective (Eagly & Chaiken, 1993; Hovland, Janis, & Kelley, 1963). These approaches to attitudes focused on the cognitive processes that people use when evaluating messages and on the relationship between attitudes and behavior. Leon Festinger’s important cognitive dissonance theory was developed during this time and became a model for later research (Festinger, 1957).

In the 1970s and 1980s, social psychology became even more cognitive in orientation as social psychologists used advances in cognitive psychology, which were themselves based largely on advances in computer technology, to inform the field (Fiske & Taylor, 2008). The focus of these researchers, including Alice Eagly, Susan Fiske, E. Tory Higgins, Richard Nisbett, Lee Ross, Shelley Taylor, and many others, was on social cognition—an understanding of how our knowledge about our social worlds develops through experience and the influence of these knowledge structures on memory, information processing, attitudes, and judgment. Furthermore, the extent to which humans’ decision making could be flawed due to both cognitive and motivational processes was documented (Kahneman, Slovic, & Tversky, 1982).

In the 21st century, the field of social psychology has been expanding into still other areas. Examples that we consider in this book include an interest in how social situations influence our health and happiness, the important roles of evolutionary experiences and cultures on our behavior, and the field of social neuroscience—the study of how our social behavior both influences and is influenced by the activities of our brain (Lieberman, 2010). Social psychologists continue to seek new ways to measure and understand social behavior, and the field continues to evolve. We cannot predict where social psychology will be directed in the future, but we have no doubt that it will still be alive and vibrant.

The Person and the Social Situation

Social psychology is the study of the dynamic relationship between individuals and the people around them. Each of us is different, and our individual characteristics, including our personality traits, desires, motivations, and emotions, have an important impact on our social behavior. But our behavior is also profoundly influenced by the social situation—the people with whom we interact every day. These people include our friends and family, our classmates, our religious groups, the people we see on TV or read about or interact with online, as well as people we think about, remember, or even imagine.

Social psychologists believe that human behavior is determined by both a person’s characteristics and the social situation. They also believe that the social situation is frequently a stronger influence on behavior than are a person’s characteristics.

Social psychology is largely the study of the social situation. Our social situations create social influence—the process through which other people change our thoughts, feelings, and behaviors and through which we change theirs. Maybe you can already see how social influence affected Raoul Wallenberg’s choices and how he in turn influenced others around him.

Kurt Lewin formalized the joint influence of person variables and situational variables, which is known as the person-situation interaction, in an important equation:

Behavior = f (person, social situation).

Lewin’s equation indicates that the behavior of a given person at any given time is a function of (depends on) both the characteristics of the person and the influence of the social situation.

Evolutionary Adaptation and Human Characteristics

In Lewin’s equation, person refers to the characteristics of the individual human being. People are born with skills that allow them to successfully interact with others in their social world. Newborns are able to recognize faces and to respond to human voices, young children learn language and develop friendships with other children, adolescents become interested in sex and are destined to fall in love, most adults marry and have children, and most people usually get along with others.

People have these particular characteristics because we have all been similarly shaped through human evolution. The genetic code that defines human beings has provided us with specialized social skills that are important to survival. Just as keen eyesight, physical strength, and resistance to disease helped our ancestors survive, so too did the tendency to engage in social behaviors. We quickly make judgments about other people, help other people who are in need, and enjoy working together in social groups because these behaviors helped our ancestors to adapt and were passed along on their genes to the next generation (Ackerman & Kenrick, 2008; Barrett & Kurzban, 2006; Pinker, 2002). Our extraordinary social skills are primarily due to our large brains and the social intelligence that they provide us with (Herrmann, Call, Hernández-Lloreda, Hare, & Tomasello, 2007).

The assumption that human nature, including much of our social behavior, is determined largely by our evolutionary past is known as evolutionary adaptation (Buss & Kenrick, 1998; Workman & Reader, 2008). In evolutionary theory, fitness refers to the extent to which having a given characteristic helps the individual organism to survive and to reproduce at a higher rate than do other members of the species who do not have the characteristic. Fitter organisms pass on their genes more successfully to later generations, making the characteristics that produce fitness more likely to become part of the organisms’ nature than are characteristics that do not produce fitness. For example, it has been argued that the emotion of jealousy has survived over time in men because men who experience jealousy are more fit than men who do not. According to this idea, the experience of jealousy leads men to protect their mates and guard against rivals, which increases their reproductive success (Buss, 2000).

Although our biological makeup prepares us to be human beings, it is important to remember that our genes do not really determine who we are. Rather, genes provide us with our human characteristics, and these characteristics give us the tendency to behave in a “human” way. And yet each human being is different from every other human being.

Evolutionary adaption has provided us with two fundamental motivations that guide us and help us lead productive and effective lives. One of these motivations relates to the self—the motivation to protect and enhance the self and the people who are psychologically close to us; the other relates to the social situation—the motivation to affiliate with, accept, and be accepted by others. We will refer to these two motivations as self-concern and other-concern, respectively.

Self-Concern

The most basic tendency of all living organisms, and the focus of the first human motivation, is the desire to protect and enhance our own life and the lives of the people who are close to us. Humans are motivated to find food and water, to obtain adequate shelter, and to protect themselves from danger. Doing so is necessary because we can survive only if we are able to meet these fundamental goals.

The desire to maintain and enhance the self also leads us to do the same for our relatives—those people who are genetically related to us. Human beings, like other animals, exhibit kin selection—strategies that favor the reproductive success of one’s relatives, sometimes even at a cost to the individual’s own survival. According to evolutionary principles, kin selection occurs because behaviors that enhance the fitness of relatives, even if they lower the fitness of the individual himself or herself, may nevertheless increase the survival of the group as a whole.