Assessment of the Predictors and Moderators of Health Behavior Change

This study will investigate three interventions-values clarification, planning, or combined (values clarification + planning)-for increasing goal-consistent health behavior (e.g., exercise or dieting). The investigators will also examine how intervention effects differ based on various psychological and neuropsychological factors, to better understand how interventions can be tailored to specific individuals. The investigators hypothesize a) that the combined intervention will increase goal-consistent exercise behavior more than the other interventions; and b) that individuals scoring higher on self-concordance or goal-commitment will benefit more from planning, whereas those with more positive expectancies or scoring higher on neuropsychological measures (e.g., working memory) will benefit more from values clarification.

The study will be a repeated measures design examining the between-subjects effect of intervention condition (values clarification, planning, and combined) on self-reported health goal progress and related outcomes at 1-week and 4-week follow-up, relative to baseline. Based on this design, participants will first be instructed to generate a health-related goal on which they want to make progress over the course of the next month (following procedures adapted from Little, 1993, and Sheldon \& Kasser, 1998; see details below). Participants will then be randomly assigned (using a random number table) to one of three intervention conditions: (1) values clarification, (2) planning, and (3) combined (values clarification + planning). All conditions are described in more detail below. Fifty-three participants will be randomized to each condition. Questionnaire measures assessing a variety of psychological variables as well as neuropsychological measures will be modeled as between-subject predictor and/or moderator variables of goal-consistent health behavior. Additionally, differences in self-concordance, goal commitment, and expectancies of success will be modeled as potential moderator and/or mediator variables.