A trait conceptualization of reward-reactivity

The Appetitive Motivation Scale (AMS; Jackson & Smillie, 2004) represents a recent attempt to conceptualize individual differences in the functioning of Gray's (1981) Behavioral Activation/Approach System (BAS). In this paper we subject the AMS to psychometric scrutiny via factor analysis, item response theory (IRT) analysis, and concurrent construct validation. In Study 1 (N = 1,366 university students, 53% male), results from factor analysis (FA) and IRT led to the removal of several problematic items from the scale. The revised AMS was shown to have improved unidimensional structure and item properties. In Study 2 (N = 122 university students, 20% male), correlational data and factor analysis indicated that the revised AMS was: (1) highly related to the original scale along with various BAS-related measures, and (2) more strongly related to a reward-reactivity factor than an impulsivity factor, relative to other putative BAS measures. We conclude that the improved AMS is a promising tool for future research