Page 190 - Media Effects Advances in Theory and Research

7. MASS MEDIA ATTITUDE CHANGE 179

message containing a set of strong arguments in favor of phosphate deter-
gents. All participants were told to think about the message and to list
the thoughts that came to mind. Because the message was composed of
convincing arguments, recipients generated mostly favorable thoughts
toward the proposal. After receiving the message, but just prior to report-
ing their attitudes, participants were led to believe that the message was
written either by a government environmental agency (high credibility)
or by the detergent manufacturer (low credibility source). The credibility
of the source could not affect the nature of the thoughts elicited because
this manipulation followed message processing. However, the manipula-
tion affected the confidence that participants reported in the validity of
their thoughts. That is, more confidence was reported when the message
was said to have come from a high rather than a low credibility source.
Because the arguments were strong and the thoughts mostly favorable,
relying on these thoughts produced more favorable attitudes.
Under high-elaboration conditions, the role that source factors play
depends on a number of factors. First, the source factor can serve as a
message argument if it contains information central to the merits of the
object. Otherwise, the source factor can either bias the direction of the
thoughts or affect a person’s confidence in the thoughts that are gener-
ated. The former role is more likely when the source information precedes
the message where it can influence thought generation, but if the source
information comes after the message, the latter role is more likely.
Finally, if people were made aware of the potentially biasing impact of
source factors (either on information processing or on judgment), they
might attempt to correct for this influence. For example, in one study
Petty, Wegener, and White (1998) found that highly likable sources pro-
duced less persuasion than dislikable sources when participants tried to
correct for this potential bias. This reversed effect of liking was a result of
“overcorrection” (i.e., people overestimating the effect of source likability
on their judgments; see also Wegener & Petty, 1995).

Multiple Roles for Message Factors. As we noted earlier, the mere
number of arguments in a message can serve as a peripheral cue when
people are either unmotivated or unable to think about the information.
When motivation and ability are high, however, the informational items
in a message are not simply counted as cues, but instead the information
is processed for its cogency. When the number of items in a message
serves as a cue (low-elaboration conditions), adding weak reasons in sup-
port of a position enhances persuasion, but when the items in a message
serve as arguments, adding weak reasons reduces persuasion (Aaker &
Maheswaran, 1997; Alba & Marmorstein, 1987; Friedrich, Fetherston-
haugh, Casey, & Gallagher, 1996; Petty & Cacioppo, 1984a).