In most theories of risk judgment the multiplicative combination of probabilities and payoffs is assumed. However, some authors argue and have shown empirically that risk judgment is represented by an additive combination of probability and utility. In these studies, information about probability was presented differently from information about payoffs. This, in turn, could encourage subjects to consider separately each dimension leading to their additive combination in risk judgments. Thus, here it is tested whether the empirical support for an additive combination of probability and utility could result from the way in which information about payoffs and probability was presented. Three different graphic forms of stimuli presentation were used (Experiment 1) and the easiness of information processing about either dimension was controlled (Experiment 2). In general, it has been found that information display affects the strength of main effects of utility and probability on risk rates. However, the results indicate that information display affects neither value of risk rates nor the pattern by which information is combined.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.