Teaching Tip Sheet: Motivated Reasoning

In an influential review, Ziva Kunda (1990) summarized several decades of research supporting the role of motivation in cognitive processes such as decision-making and attitude change. She claimed that motivation has been shown to affect reasoning in a number of paradigms, including:

• Cognitive dissonance reduction

• Beliefs about others on whom one's own outcomes depend

• Evaluation of scientific evidence related to one's own outcomes

Her analysis of this research led further to the conclusion that motivated reasoning is only possible when the individual is able to generate apparently reasonable justifications for the motivated belief; this happens, however, outside of the person's conscious awareness. This is achieved via bias in accessing, constructing, and evaluating beliefs.

In a recent study, Hart and Gerrard (1997) obtained support for these assertions in the context of college students' appraisals of risk of sexually transmitted disease (STD). In this study, male students were shown photographs and narrative descriptions of a series of female students and were asked to estimate the likelihood of contracting an STD as a result of having unprotected sex with each woman. In a baseline assessment, estimates were made in light of information concerning the number of sexual partners each woman had in the past, given as one, three or eight partners in the narrative, and her frequency of condom use. This information was relevant to actual risk and was included as a factor that could inform "rational" risk appraisals.

In a subsequent experimental trial, motivation was manipulated by varying the sexual attractiveness of the women appearing in the photographs. The assumption was that, when confronted with a potential (if hypothetical) sex partner, motivation to believe her to be low-risk for negative consequences would be affected by her sexual desirability. Another manipulation varied whether the participant was given sufficient information regarding the potential partner to enable justification of the motivated reasoning. This information, which described aspects of the woman's personality, was in fact irrelevant to actual risk. Each participant responded to nine stimuli, which were presented in counterbalanced order.

Results provided support for the existence of motivated reasoning in this important arena. Male students rated the attractive women as carrying less risk of STD infection compared to the less attractive women, but only when information enabling the construction of justifications for these judgments had been provided. This phenomenon may occur frequently in naturalistic environments and may contribute to infection by HIV and other STDs in the "real world." This study is important because it casts doubt on the utilitarian, "rational" models of behavioral decision making upon which most research in health promotion/disease prevention currently rests.

The instructor could conduct a small-scale replication of this study in the classroom, presenting the stimuli to the class and asking for their ratings, and then tabulating the results to present during the next class session.

Blanton, H., & Gerrard, M. (1997). Effect of sexual motivation on men's risk perception for sexually transmitted disease: There must be fifty ways to justify a lover. Health Psychology, 16(4), 374-379.

Kunda, Z. (1990). The case for motivated reasoning. Psychological Bulletin, 108(3), 480-498.