Page 33 - Media Effects Advances in Theory and Research

22 ZILLMANN

assessments, such as incidence proportions and rates of change of occur-
rences. They may convey data that are collected in adherence to the princi-
ples of science. Information of this kind has been labeled base-rate informa-
tion. It is generally considered to be less partial and hence more veridical
than the information provided by selective exemplar aggregations. On
occasion, such information gives impetus to news reports. On other occa-
sions, it is furnished to correct likely misperceptions presumed to result
from biased exemplification. More often than not, however, base-rate infor-
mation is simply not reported, often because it is not known. In such cases,
the perception of phenomena hinges entirely on the provision of exemplars.
Irrespective of the reasons for including base-rate information in the
projection of phenomena, the issue of misperception from exposure to
admixtures of selective exemplification and potentially more reliable
base-rate information is defined by the reception of these messages. How
will recipients process the information? Will they base their perception of
issues primarily on the display of exemplars? This can be expected on
grounds of the built-in heuristics that ensured the survival of the species.
Or will recipients absorb the comparatively abstract base-rate informa-
tion, process it carefully, and use it to correct false impressions invited by
inappropriate exemplar aggregations? Those who believe in the careful
digestion of news reports may expect that base-rate information does
have this power to put exemplars in their place as mere illustrations,
thereby depriving them of undue influence. On the other hand, the pro-
cessing of less concrete, more abstract information may be considered
evolutionarily too vernal to be capable of overpowering the impressions
based on the deep-rooted mechanisms of extrapolating tacit knowledge
about a population of events from a handful of actually known ones. Of
particular interest are the delayed consequences of the provision of con-
crete versus abstract information. Are incidence rates and the like as well
retained as concrete events, especially concrete events associated with
strong emotions? If not, should it not be expected that the influence of
base-rate information on the perception of issues will diminish more
rapidly than that of exemplification, ultimately allowing the exemplar
influence to become increasingly dominant?
These are some of the questions that exemplification theory addresses
and that the reported experimental work seeks to answer.

DEFINITIONAL CLARIFICATION

Exemplars describe events. Not all events are exemplars, however. A sin-
gular event that does not share any features with other events is, by defi-
nition, not a member of a population of like events. Unique events, there-
fore, stand for themselves only and do not exemplify anything.