12.4 SUMMARY

• Survival and reproduction require scarce resources, and aggression and cooperation are two ways to get them.
• Aggression often results from negative affect. The likelihood that people will aggress when they feel negative affect is determined both by biological factors (such as testosterone level) and cultural factors (such as geography).
• Cooperation is beneficial but risky, and one strategy for reducing its risks is to form groups whose members are biased in favor of each other. Unfortunately, groups often decide and behave badly.
• Both biology and culture tend to make the costs of reproduction higher for women than for men, which is one reason why women tend to be choosier when selecting potential mates.
• Attraction is determined by situational factors (such as proximity), physical factors (such as symmetry), and psychological factors (such as similarity).
• People weigh the costs and benefits of their relationships and tend to dissolve them when they think they can or should do better, when they and their partners have very different cost– benefit ratios, or when they have little invested in the relationship.

• People are motivated to experience pleasure and avoid pain (the hedonic motive), and thus can be influenced by rewards and punishments, although these can sometimes backfire.
• People are motivated to attain the approval of others (the approval motive) and thus can be influenced by social norms, such as the norm of reciprocity. People often look to the behavior of others to determine what’s normative, and they often end up conforming or obeying, sometimes with disastrous results.
• People are motivated to know what is true (the accuracy motive) and thus can be influenced by other people’s behaviors and communications. This motivation also causes them to seek consistency among their attitudes, beliefs, and actions.

• People make inferences about others based on the categories to which they belong (stereotyping). This method can lead them to misjudge others because stereotypes can be inaccurate, overused, self-perpetuating, and unconscious and automatic.
• People make inferences about others based on others’ behaviors. This method can lead to misjudgments because people tend to attribute actions to dispositions even when they should attribute them to situations.