Randomly select a group of people to listen to a speaker's administrative ethics speech to a large group of highly attentive listeners  Then randomly select another group of people to listen to the same content of the speaker's speech to a small group of less attentive listeners
If the second group listened to the speaker's first speech, they would make very different judgments
 The former group believes that the speaker is thoughtful and confident; The latter group believed that his expression was vague and lengthy