I recently had the chance to talk with Marty Fishbein, the author of the Theory of Reasoned Action (TRA) - one of the most frequently employed theories in health education and health behavior circles. We were attending the Health Communication Symposium where a poster he was an author of, “Towards an understanding of the role of normative influence on cancer-related behaviors,” had gotten my interest. It was several minutes before the official program began, and he offered to come back with me to the poster and talk about the findings and their implications for behavior change efforts.
The research looked at how various components of TRA could be used to predict people’s stated intentions to do six different cancer-related behaviors: get a colonoscopy, mammogram or PSA test (if it’s already recommended for someone of the person’s age), exercise at least 3X/week, eat 5 servings of fruits and vegetables a day, and go on a diet if they were overweight. As Marty explained it, the ‘injunctive norm’ variable in TRA has been shown to be a fairly good predictor of intentions to engage in screening behaviors, but pretty poor with intentions to do more complex behaviors such as exercising and eating. In this study, they decided to add another type of normative variable to the mix: ‘descriptive norms.’ And as you may have guessed, the descriptive norm variable turned out to be quite predictive of intentions to engage in the more complex behaviors while the injunctive norm maintained its superior predictive power with the screening behaviors. Here’s how they measured the two norms:
Injunctive norm: Do most people you know who are important to you think that you should or should not get/do …? [1 (definitely not) – 5 (definitely should)].
Descriptive norm: How many of the people most similar to you got…? How many of the people most important to you do …? [1 (none) – 4 (all or almost all)].
He drew the distinction between the two as the injunctive norm being one more psychological in nature whereas the subjective norm is more of a sociological construct. While he is still working out the theoretical implications for these findings, they did draw two practical implications from the work that social marketers and health communicators should keep in mind as they focus on different types of behavior change:
Very different communications will be necessary to increase the likelihood that people engage in screening behaviors than to increase the likelihood that they will engage in lifestyle behaviors.
Communications focusing on screening behaviors should emphasize injunctive norms while, depending upon the behavior, those addressing lifestyle behaviors should focus on perceived control, attitudes or subjective norms.
Take home: ‘Just do it because we think you should’ vs ‘Just do it because we do’ isn’t just a semantic exercise, but one with real consequences for the effectiveness of the behavior and social change enterprise.