What makes attitudes change, and do they predict behaviour?

Whether an attitude changes depends on four things.

1. The existing attitude: extreme, central and complex attitudes resist change. Congruent change (making a positive attitude more positive, or a negative one more negative) is easier than incongruent change (turning a positive attitude negative).

Using fear in a message works only up to a point: too much fear makes people turn off, deny the danger, and ignore the message.

2. The source: a source with high credibility (expertise, trustworthiness) and attractiveness changes attitudes more.

3. The message:

• Just enough information: too little is unconvincing; too much is confusing.
• Rational or emotional appeal: 'a pressure cooker saves cooking gas' is a rational appeal; showing a happy family enjoying a meal is an emotional one.
• Appeals to motives: health, beauty, saving money.
• Mode of transmission: face-to-face is usually more effective than letters and pamphlets.

4. The target (the person to be persuaded): their persuasibility, their prejudices, their self-esteem (people with high self-esteem are less easily changed), and their intelligence.

Do attitudes predict behaviour? Only under some conditions. In the 1930s, Richard LaPiere travelled across the US with a Chinese couple, at a time of strong prejudice against Chinese people. They were refused service only once in over 250 places. Yet when LaPiere later wrote asking whether these places would serve Chinese guests, most said no. Their attitudes did not match their behaviour.

Sometimes it works the other way: behaviour shapes attitude, as in the dissonance experiment.

So who says what to whom matters.