D. Vanknippenberg et al., IN-GROUP PROTOTYPICALITY AND PERSUASION - DETERMINANTS OF HEURISTIC AND SYSTEMATIC MESSAGE PROCESSING, British journal of social psychology, 33, 1994, pp. 289-300
Self-categorization theory (Turner, Hogg, Oakes, Reicher & Wetherell,
1987) proposes that identification with a social group will elicit a t
endency to conform to in-group norms. Following this proposition, we a
rgue that the extent to which persuasive ingroup communication is perc
eived to reflect in-group norms, that is, is prototypical, will affect
attitudes. Attitudes are predicted to be more affected by exposure to
prototypical messages. Moreover, it is argued that prototypicality mi
ght both instigate systematic message processing and function as a heu
ristic cue. Whether systematic processing will occur was hypothesized
to be dependent on the availability of cues enabling heuristic process
ing. A study was designed in which subjects were exposed to a persuasi
ve message from either a prototypical or an non-prototypical in-group
source. In half of the conditions, subjects were informed about the op
inion of the source before message exposure (which would enable heuris
tic processing). Quality of the message (i.e. strong vs. weak argument
s) and position advocated by the message were experimentally varied. I
t was predicted that prototypicality would elicit conformity to in-gro
up norms, but that it would only instigate systematic processing when
subjects had no foreknowledge about the source opinion. Results suppor
ted these predictions.