Bringing Meaning to Numbers: The Impact of Evaluative Categories on Decisions

Journal of Experimental Psychology: Applied, Vol. 15, No. 3, pg. 213-227.

Ellen Peters, Nathan F. Dieckmann, Daniel Västfjäll, C. K. Mertz, Paul Slovic, Judith H. Hibbard

Decision makers are often quite poor at using numeric information in decisions. The results of 4 experiments demonstrate that a manipulation of evaluative meaning (i.e., the extent to which an attribute can be mapped onto a good/bad scale; this manipulation is accomplished through the addition of visual boundary lines and evaluative labels to a graphical format) has a robust influence in health judgments and choices and across diverse adult populations. The manipulation resulted in greater use of numeric quality-of-care information in judgments and less reliance on an irrelevant affective state among the less numerate. Recall results for provided quality-of-care numbers suggested that the manipulation did not influence depth of number processing with the exception of cost information that was not remembered as well. Results of a reaction-time paradigm revealed that feelings were more accessible than thoughts in the presence of the manipulation, suggesting that the effect may be due, at least in part, to an affective mechanism. Numeric information is often provided in decisions, but may not be usable by consumers without assistance from information providers. Implications for consumer decision making and the functions of affect are discussed.

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