关键词: 跨期选择, 延迟折扣, 维度间差异比较

Abstract: Previous studies have concentrated on intertemporal choice with monetary outcomes and only a few of research investigated that with non-monetary outcomes. These studies found that people show goods-specific discounting rates. In daily life, people often make decisions among commodities of different qualities of same kind that occurs at different times, which is scarcely investigated. Based on the multi-attribute theory and the attribute-based intertemporal theory, the present study proposes that individuals are more patient when facing commodities of different qualities than facing monetary outcomes. This is because that the difference perceptions between these different quality commodities are greater than that of corresponding monetary outcomes. Further more, we suppose that the psychological process of intertemporal choice with different quality commodities is based on the dimensional difference-comparing process, which is the same as those with monetary outcomes. Three experiments were performed to test these hypotheses and all were conducted with between-subjects designs. In experiment 1, participants (322 adults, 118 men) were shown 4 paired options with one sooner-smaller outcomes (SS) and the other later-larger outcomes (LL). Half of the participants indicated their preference for monetary outcomes (money condition) and the other half the different corresponding commodities of same kind (quality condition). This was to examine whether individuals are more patient in the quality condition than in the money condition. Experiment 2 was to test whether the perceived difference between these different quality commodities are greater than that of corresponding monetary outcomes. Participants (428 adults, 196 men) were randomly assigned to two conditions and firstly made choice between SS and LL, then they were asked to indicate their perceived difference on the outcome dimensions. Experiment 3 was to figure out whether one’s preference was mediated by the dimensional difference-comparing process. Participants (424 adults, 194 men) were asked to indicate their preferences and to compare the differences on the delay dimension with that on the outcome dimension. The results of Experiment 1 and Experiment 2 showed that more individuals preferred later but larger outcomes in quality condition (vs. money condition) in intertemporal choice. In other words, they tend to be more patient in quality condition (vs. money condition) in intertemporal choice. Furthermore, compared with money condition, individuals felt greater perceived difference on the outcome dimension in quality condition. And this perceived difference on the outcome dimension mediated the preferences between two conditions. The results of Experiment 3 showed the perceived difference between the outcome dimension and the delay dimension is larger in quality condition than in money condition, to be specific, participants felt the outcome dimension is larger than that on the delay dimension in quality condition, which mediates the choice results. To be a conclusion, the results of the three experiments show that individuals are more patient when facing different quality commodities of the same kind than when facing monetary outcomes. The reason of which is when facing with quality commodities outcomes, participants felt greater perceived difference on the outcome dimension than monetary outcomes. Furthermore, this study finds that the psychological process of intertemporal choice of quality outcome is consistent with that of monetary outcome, it also follows the dimensional difference-comparing process. These findings enrich the research of intertemporal choice and have significant implications for attribute-based intertemporal choice models.

Key words: intertemporal choice, delay discounting, dimensional difference-comparing process