Both thoughtful and spontaneous messages can be effective, but it is important to know which is likely to be better in which situation and for which people. When we can motivate people to process our message carefully and thoughtfully, then we are going to be able to present our strong and persuasive arguments with the expectation that our audience will attend to them. If we can get the listener to process these strong arguments thoughtfully, then the attitude change will likely be strong and long lasting. On the other hand, when we expect our listeners to process only spontaneously—for instance, if they don’t care too much about our message or if they are busy doing other things—then we do not need to worry so much about the content of the message itself; even a weak (but interesting) message can be effective in this case. Successful advertisers tailor their messages to fit the expected characteristics of their audiences.
In addition to being motivated to process the message, we must also have the ability to do so. If the message is too complex to understand, we may rely on spontaneous cues, such as the perceived trustworthiness or expertise of the communicator (Hafer, Reynolds, & Obertynski, 1996), and ignore the content of the message. When experts are used to attempt to persuade people—for instance, in complex jury trials—the messages that these experts give may be very difficult to understand. In these cases, the jury members may rely on the perceived expertise of the communicator rather than his or her message, being persuaded in a relatively spontaneous way. In other cases, we may not be able to process the information thoughtfully because we are distracted or tired—in these cases even weak messages can be effective, again because we process them spontaneously (Petty, Wells & Brock, 1976).
Petty, Cacioppo, and Goldman (1981) showed how different motivations may lead to either spontaneous or thoughtful processing. In their research, college students heard a message suggesting that the administration at their college was proposing to institute a new comprehensive exam that all students would need to pass in order to graduate, and then rated the degree to which they were favorable toward the idea. The researchers manipulated three independent variables:
- Message strength.The message contained either strong arguments (persuasive data and statistics about the positive effects of the exams at other universities) or weak arguments (relying only on individual quotations and personal opinions).
- Source expertise.The message was supposedly prepared either by an expert source (the Carnegie Commission on Higher Education, which was chaired by a professor of education at Princeton University) or by a nonexpert source (a class at a local high school).
- Personal relevance.The students were told either that the new exam would begin before they graduated (high personal relevance) or that it would not begin until after they had already graduated (low personal relevance).
As you can see in Figure 4.8, Petty and his colleagues found two interaction effects. The top panel of the figure shows that the students in the high personal relevance condition (left side) were not particularly influenced by the expertise of the source, whereas the students in the low personal relevance condition (right side) were. On the other hand, as you can see in the bottom panel, the students who were in the high personal relevance condition (left side) were strongly influenced by the quality of the argument, but the low personal involvement students (right side) were not.
These findings fit with the idea that when the issue was important, the students engaged in thoughtful processing of the message itself. When the message was largely irrelevant, they simply used the expertise of the source without bothering to think about the message.
Because both thoughtful and spontaneous approaches can be successful, advertising campaigns, such as those used by Apple, carefully make use of both spontaneous and thoughtful messages. For example, the ad may showcase the new and useful features of a device like the iPad amid scenes of happy, creative, or productive people and an inspiring soundtrack.