Modeling effort decisions with behavioral decision theory: Toward an individual differences model of expectancy theory

Abstract

Using behavioral decision theory, this paper describes four experiments which tested the multiplicative force model from V. H. Vroom's (1964, Work and Motivation, New York: Wiley) Expectancy Theory. In the first two experiments, the academic course effort decisions of 68 graduate students were examined using a decision-making exercise involving 24 hypothetical courses. Each course was described in terms of three instrumentalities and one expectancy (0, .4, or .8 in the first experiment, and 0, .2, or .6 in the second experiment). Using two different decision-making exercises, the last two experiments captured the decisions of 89 high school and undergraduate students concerning the exertion of effort to get 24 hypothetical jobs. For the third experiment, each job was described in terms of three instrumentalities and one expectancy (.05, .50, or .95). For the fourth experiment, each job was described in terms of four instrumentalities and one expectancy (0, .3, or .6). In each of the four experiments, the instrumentalities and expectancies were presented using factorial designs in order to increase the level of experimental control and to provide a sufficient number of decisions for each subject to facilitate individual within-person analyses of the data. Vroom's multiplicative force model was supported by only a minority of the subjects; a majority supported an additive model. It is hypothesized that the two different models are attributable to individual differences in cognitive processing of probabilistic information. This research demonstrates the theoretical, analytic, and psychometric advantages of the behavioral decision theory modeling approach to testing Expectancy Theory.