Page 173 - Media Effects Advances in Theory and Research

162 PETTY, PRIESTER, BRIÑOL

the maximum probability of achieving all six steps (exposure, attention,
6
interest, comprehension, learning, and yielding), would be .6 , or only 5%.
In addition, it is important to consider the fact that any one input vari-
able can have different effects on the different output steps. For example,
Hyman and Sheatsley (1947) noted that in the political domain, the
knowledge and interest of a message recipient was positively related to
exposure to political messages (i.e., the chronic “know-nothings” are
more difficult to reach in a political campaign), but negatively related to
attitude change (i.e., high interest and knowledge tends to produce assim-
ilation of messages to one’s original point of view). In a cogent analysis of
this point, McGuire (1968) noted that several variables might have oppo-
site effects on the steps involving reception of information (e.g., exposure,
attention, comprehension, acquisition, memory) versus acceptance of
(yielding to) the information. For example, the intelligence of the message
recipient is related positively to reception processes, but negatively
related to yielding. The joint action of reception and yielding processes
implies that people of moderate intelligence should be easier to persuade
than people of low or high intelligence, as this maximizes both reception
and yielding (see also Rholes & Wood, 1992).

Additional Issues for the Communication/Persuasion Matrix Model.
Although McGuire’s input/output matrix model serves as a very useful
way to think about the steps involved in producing attitude and behavior
change via the mass media or other means, it is important to appreciate a
number of things that the model does not address. First, it is now clear
that some of the steps in the postulated information processing sequence
may be completely independent of each other, rather than sequential. For
example, although a person’s ability to learn and recall new information
(e.g., facts about a political candidate) was often thought to be an impor-
tant causal determinant of and prerequisite to attitude and behavior
change (e.g., favoring and voting for a candidate), little empirical evidence
has accumulated to support the view that message learning is a necessary
step for persuasion (Greenwald, 1968; McGuire, 1985; Petty & Cacioppo,
1981). Rather, the existing evidence shows that message comprehension
and learning can occur in the absence of attitude change and that a per-
son’s attitudes can change without learning the specific information in the
communication. That is, a person might be able to comprehend all of
the intended information perfectly, but not be persuaded either because
the information is counterargued or seen as personally irrelevant. On the
other hand, a person might get the information all wrong (scoring zero on
a knowledge or recall test), but think about it in a manner that produces
the intended change. That is, misunderstanding the message can some-
times produce more change than correct understanding.