Risk taking, frame of reference, and characterization of victim groups in AIDS treatment decisions

Abstract

Subjects' frame of reference was manipulated in a hypothetical medical decision-making task patterned after Tversky and Kahneman's (1981) "Asian disease task". Subjects in the positive framing condition received an option of definitely saving one-third of the lives of potential victims of a new outbreak of AIDS and an option with a one-third probability of saving all lives and a two-thirds probability of saving no lives. Equivalent options in the negative framing condition were one where two-thirds would die and one where there is one-third probability no one would die and two-thirds probability that all would die. Characteristics of the potential groups of victims were also manipulated. Results for the more desirable victim group, hemophiliacs, displayed the usual preference reversal with changing frame of reference: risk-averse choices when considering "lives saved" and risk-seeking choices when considering "lives lost". This was not the case for the less desirable groups, e.g., intravenous drug users. These results were replicated in a forced-choice variant of the task. Analogous results were obtained when comparing risk-taking for "ingroup" and "outgroup" members. Results were discussed in terms of differences in the subjective value functions for "lives saved" and "lives lost" for the different groups. An independent scaling procedure supported the hypothesized differences in value functions.