How Social Are Humans?
The chapter begins with Baumeister and Leary's need to belong theory that states that the need for interpersonal attachments is a fundamental motive that has evolved for adaptive purposes. This theory is supported by the finding that people feel anxious when they face exclusion from their social groups (social exclusion theory). It is hypothesized that we have evolved cheater detectors that are especially sensitive to violations in social exchanges. Thus, although individuals may be motivated to act selfishly for short-term gain, they are inhibited by the possibility of being detected and facing long-term social punishment and rejection. Additional supporting evidence of the need to belong is seen in Stanley Schachter's classic affiliation study. Research participants faced with an anxiety-producing situation chose to affiliate with other anxious participants. This led to Schachter's often-quoted line that “misery loves miserable company.”

What Information Is Contained in Nonverbal Behavior?
The advantages of living with others resulted in the need to communicate. We are adept at forming immediate impressions of others through both verbal and nonverbal information. Nonverbal information is communicated through facial expressions, gait, posture, gestures, and vocal cues. However, despite our facility with these channels of data, we are poor at detecting deception. This leads to the interesting proposal that deception is a prerequisite for harmonious human interaction. Finally, although we appear to be innately predisposed to communicating nonverbally, the form of one's body language can vary widely between cultures as seen in the regulation of personal space and gestures.

How Do People Manage Their Public Impressions?
The need to belong also influences how we want to be seen by others. We want to be viewed as competent and contributing members who would be desirable to the group. Therefore, we have developed a number of strategies for positive self-presentation. One must be careful with impression management techniques because they can easily backfire, particularly among people who know us well. Individuals who are high in the trait of self-monitoring are especially likely to monitor and regulate their public image.

Table 14.1: Self-Presentation Strategies
Strategy	Process/Goal
Ingratiation	convincing others that you are likable
Self-promotion	showing one's competence and aptitude to gain others' respect
Exemplification	convincing others that you are, by example, a morally virtuous person
Intimidation	demonstrating importance and power over others through words and actions
Supplication	stressing one's weaknesses to elicit sympathy and assistance

When Does Social Power Influence Others?
Because groups are so important to us, they exert a powerful influence over our behavior. In fact, the power of social situations is much greater than most people believe, and individuals will often act in ways that greatly contradict their personal standards. The processes of social facilitation, social loafing, and deindividuation show how groups can influence individual behavior, sometimes in dangerous ways. Groups can make terrible decisions, such as in the case of the launching the space shuttle Challenger; thus it is necessary for individuals to understand the tendency toward group polarization.

Individuals conform to social norms, even when there may be obvious reasons not to do so. Those aware of strategies of social influence may use the techniques of foot in the door, door in the face, and low balling to gain compliance. A rather frightening demonstration of the power of social influence was provided by Stanley Milgram's classic studies on obedience to authority. He showed that one can get others to engage in horrible, antisocial acts simply through the power of the social context and by being insistent.

When Do People Harm or Help Others?
In the next section, the authors present data from psychological science on when individuals are likely to harm or help others. Aggression, behavior intended to harm someone else, is related to frontal lobe dysfunction and low levels of serotonin. It also stems from frustration and situations that elicit negative affect. Although men are more physically aggressive than women, they show similar levels of verbal aggression. Societal factors such as a culture of honor also can factor into displays of aggression. On the other side, humans engage in amazingly prosocial and altruistic acts. This is particularly evident when the person in need is a relative. Surprisingly, having more people around when in need does not increase your chances of getting help (bystander intervention effect) due to a diffusion of responsibility and fear of making social blunders.

What Determines the Quality of Relationships?
The final section of the chapter looks at the factors that influence some of our most critical social decisions—the choice of friends and relationship partners. These choices are affected by variables such as proximity, similarity, and physical attractiveness. The controversial sexual strategies theory suggests that men and women differ on mating strategies based on what is evolutionarily adaptive for them. Therefore, men may seek women who look as if they could bear healthy children, whereas women search for mates who have the resources necessary to nurture offspring.

Our society places a great emphasis on love and a distinction is made between the intense longing of passionate love and the long-term commitment of companionate love. Divorce statistics indicate that making love last is a difficult proposition. Relationships are challenged by the fading of passion, jealousy from extramarital affairs, and maladaptive strategies for coping with conflict. Happy couples explain their partner's behavior through partner-enhancing attributions, but unhappy couples make distress-maintaining attributions.