Self-determination and functional persuasion to encourage physical activity

Abstract

This research advances a novel approach to promoting physical activity, based on the principle of functional matching in persuasion, and the self-concordance (SC) of people's motivations for physical activity. We propose that SC establishes a positive or negative orientation toward the challenge inherent in physical activity, and that the maximum yield of participation will be achieved by communications that appeal to each orientation. In two studies, we compared how messages emphasizing challenge versus available social support would influence recipients’ self-reported practices of physical activity and attitudes toward a physical activity setting. As hypothesized, these messages had differential effects for recipients whose pursuit of physical activity varied in SC, such that favorable outcomes were more reliably associated with challenge-oriented messages among respondents higher in SC versus support-oriented messages among respondents lower in SC. The findings suggest the merits of using self-regulatory, compared with object- or personality-based, constructs and measures to indicate psychological functions of ongoing health-related behaviors.

Keywords:

• Self-determination theory
• attitude functions
• functional matching
• physical activity
• health promotion
• health-related behaviors

Acknowledgments

Study 2 was reported in the second author's undergraduate honors thesis, under the first author's supervision. Both studies were presented at the 2001 annual convention of the Society for Personality and Social Psychology. The authors are grateful to the Max Bell Foundation, University of Manitoba, and the Winnipeg Foundation for grants in support of the evaluation research project that provided data for the secondary analysis in Study 1. We thank Neal Feigenson and Jacquie Vorauer for comments on an earlier version of this article.

Notes

¹The respondents who did not identify physical activity as their most important goal undoubtedly included many who were seriously pursuing physical activity, nonetheless, as a means of achieving their primary goal. For example, 73 (15%) respondents identified weight loss, and 116 (24%) identified improving/maintaining general health or both physical and mental health, as their primary goal. The distribution of SC among respondents with a primary physical activity goal was virtually the same as among respondents as a whole.

²The median split procedure is discouraged because it effectively discards information that is contained in a continuous scale. We performed a regression analysis of physical activity, in which respondents’ continuously scaled SC and recalled frequency of receiving communications of each type were entered together on step 1, followed by product terms representing the SC × communication interactions on step 2. The step 1 findings revealed small but significant positive associations with physical activity for respondents’ SC, β = 0.16, p = 0.01, and recalled frequency of receiving both challenging and clearly supportive communications, βs = 0.18 and 0.14, ps < 0.01 and 0.05, respectively. Distantly supportive recalled communications were significantly negatively associated with physical activity overall, β = −0.14, p < 0.05. None of the product terms entered on step 2 was significantly associated with physical activity. We judged these interaction findings to be inconclusive, owing to the low statistical power of this type of analysis in field, as opposed to experimental, research (Cohen, 1988; Jaccard, Turrisi & Wan, 1990; McClelland & Judd, 1993). Because observations made in the field will tend to cluster near the center of the joint distribution of the predictor variables, even a large sample is apt to include relatively few cases that can clearly separate interactions from their component main effects.