Attitudes are our positive or negative evaluations of an attitude object. Our attitudes are based on the ABCs of affect, behavior, and cognition. Some attitudes are more important than others because they are more useful to us and thus have more impact on our daily lives. The importance of an attitude, as assessed by how quickly it comes to mind, is known as attitude strength.

The affective, behavioral, and cognitive components of attitudes normally line up or match—this is the idea of attitude consistency. Because of this consistency, our attitudes (as assessed on self-report measures) normally predict our behavior.

We may be able to change attitudes by using persuasive communicators who deliver persuasive messages to message recipients. In general, persuasion will be greater when the communicator appeals to our self-interest. Thus attractive, trustworthy, and expert communicators, who present their messages confidently and fairly and who do not appear to be influenced by situational forces, are most effective.

Persuasive messages may be processed either spontaneously or thoughtfully. In some cases, the spontaneous and emotional processing of messages may be effective because the positive or negative affect makes the message more salient, causing it to grab our attention. We are more willing and able to process information thoughtfully when the information allows us to meet underlying goals—for instance, when the message is personally relevant to us. We also process more thoughtfully when we have the ability and motivation to do so.

We may be able to help people develop a resistance to persuasion by reminding them that a persuasive message will be coming and having them practice how they will respond to influence attempts. These techniques are called forewarning and inoculation, respectively. Persuasion attempts may sometimes create reactance and thus be ineffective.

Self-perception occurs when individuals use their own behavior to help them determine their attitudes toward an attitude object. That is, we may use our own behavior as a guide to help us determine our own thoughts and feelings, based on the assumption that our thoughts and feelings should be consistent with our behaviors.

When the social situation actually causes a behavior but the individual does not realize that the social situation was the cause, we call the phenomenon insufficient justification. Overjustification occurs when we view our behavior as caused by the situation, leading us to discount the extent to which our behavior was actually caused by our own interest in it.

The discomfort that occurs when we behave in ways that we see as inappropriate, such as when we fail to live up to our own expectations, is called cognitive dissonance. Dissonance can be reduced by changing behavior, by convincing ourselves that the behavior was not so negative, or by creating new consonant cognitions.

Persuaders may use principles of attitude-behavior consistency to create attitude change, for instance, through techniques such as the foot-in-the-door technique, the low-ball technique, and the bait-and-switch technique.