Interactions between framing effects and outcome type: Aspiration levels and utility functions.

摘要

The usefulness of a utility function-based explanation and an aspiration level-based explanation for interactions between framing effects and outcome type was examined. A utility function-based explanation explains outcome type effects through differences in the shape of the utility function, with more nonlinear functions for more valuable outcome types. An aspiration level-based explanation predicts higher aspiration levels for more valuable outcome types, and different aspiration levels adopted in the positive and negative frame. In Experiment 1, participants presented with scenarios about animal and human life were found to more readily show framing effects for humans than animals, but this interaction was dependent on whether participants were given a caring manipulation (pictures of the victims) prior to addressing the scenario, and on the size of the group at risk. In Experiments 2a and 2b, utility functions were plotted for human and animal life, and televisions. More participants produced nonlinear utility functions when presented with pictures, for both human life and animal life, and these functions were more nonlinear at a group level than those produced for the less valuable outcome type (televisions). However, no significant differences were found between functions for animal and human life. In Experiment 3, an aspiration level was introduced prior to plotting utility functions for participants. Introducing an aspiration level had a large effect on risk preferences for gains and losses, producing risk-seeking for gains and risk-aversion for losses in the area of the function surrounding the aspiration level. In a follow-up study, aspiration levels were shown to be higher for human life than animal life, but not significantly different between the positive and negative frames. Based on these findings, I concluded that a combination of the utility function explanation and the aspiration level explanation was necessary to account for the findings of Experiment 1 and those in past studies: Aspiration levels are formed according to the type of outcome at stake (higher aspiration levels for more valuable outcomes), and the shape of the utility function establishes the risk preferences, which then competes with aspiration level to determine choice.