Abstract: In the field of decision theory, the tension between normative and descriptive theories has been a constant object of debate. The criterions used to evaluate normative and descriptive theories, however, differ from each other. This study sought a consistent criterion to evaluate both normative and descriptive decision theories and thus to explore the “true” rule of decision making. We hypothesized that (1) individuals would experience more positive emotions and show more acceptance when making decision according to their own rule (“true” rule) than according to a pseudo-rule; (2) the greater number of the same decision derived from decision makers’ own rule (“true” rule) and the imposed rule, the more positive emotions and acceptance would be reported.
To test these hypotheses, the expected value theory (normative theory) and the equate-to-differentiate the-ory (descriptive theory) were selected as two candidates of imposed rule. One hundred and twenty college stu-dents were asked to make risky choices according to their own rule (self-rule condition) and according to the two imposed rules (imposed rule condition), expected value rule and equate-to-differentiate rule, respectively. In the self-rule condition, participants rated their emotions after making choices according to their own rule. In the imposed rule condition, participants rated their emotions and acceptances of the two imposed rules after making choice according to the imposed rules. The order of the two imposed rules was counterbalanced across participants. We used the McNemar test to compare the decisions made under the self-rule condition and the imposed rule condition, and repeated measured ANOVAs to test the differences on emotion and acceptance ratings between the self-rule and the imposed rule conditions.
The results revealed that (1) participants reported more positive emotion when making choices according to their own rules than to imposed rules; (2) the greater number of the same decisions derived from the imposed and “true” rules, the more acceptance and positive emotion reported by the participants; (3) equate-to-differentiate rule is more likely to be consistent with decision makers’ true rule than expected value rule. These findings supported our hypotheses.
As a new attempt to test normative and descriptive theories, the experiencing of imposed rule would possi-bly help us to better understand what the decision makers’ true rule is. Considering that expectation rule is deemed as the soul of the dominant normative theories of decision-making under risk, our findings suggested that normative theories might fail to capture the nature of individuals’ risky choice. In contrast, descriptive theories (e.g., the equate-to-differentiate theory) seem to provide a better explanation to understand the actual mechanism of decision making under risk.

Key words: normative theory, descriptive theory, Expected Value theory, Equate-to-differentiate theory, imposed rule