Exercise as the sum of our choices between behavioral alternatives: The Decisional Preferences in Exercising (DPEX) test.

Exercising can be theorized as the result of choosing one behavior over alternative behaviors. The Decisional Preferences in Exercising (DPEX) test is a computerized, easy-to-use, publicly available (open source Python code: https://osf.io/ahbjr/) and highly adaptive research tool based on this rationale. In the DPEX, participants are asked to choose between two images by pressing a key on the computer keyboard, one showing a physical exercise and the other showing a non-exercise behavioral alternative in a series of trials. Combinations are randomly assembled from two definable pools of stimuli trial-per-trial. The test can be scored either based on a crossed random effects model (facilitating the use of different stimulus material in different studies without compromising the comparability of test scores) or with a simple proportion score. Data from diverse study samples (N = 451) showed strong correlations of DPEX scores with past and future exercise behavior (r = 0.42 and 0.47 respectively) as well as with affective experiences with exercise (e.g., 'pleasure-displeasure': r = 0.47). DPEX test scores discriminated between exercisers and non-exercisers according to receiver operating curve (ROC) analysis. The DPEX may be used to examine research questions derived from dual process theories, the effects of psychological states on behavioral choices can be tested, or the effects of behavior change interventions can be evaluated. The DPEX helps to avoid common method bias in the assessment of exercise behavior, for example, when psychological variables are measured with questionnaires.