Tell Me a Story About Healthy Snacking and I Will Follow: Comparing the Effectiveness of Self-Generated Versus Message-Aided Implementation Intentions on Promoting Healthy Snacking Habits Among College Students

Abstract

In the context of healthy snacking, this study examines whether the quality of mental imagery determines the effectiveness of combining the implementation intention (II) intervention with mental imagery. This study further explores whether providing narrative healthy snacking scenarios prior to forming an II enhances people’s mental imagery experience when they are not motivated to snack healthfully. A 2 × 2 factorial design was employed to test the main effect of providing healthy snacking scenarios prior to II formation, and whether such effect depends on people’s motivation level. The results from the experiment (N =148) showed significant main as well as interaction effects of the manipulation (with vs. without reading healthy snacking scenarios prior to II formation) and motivation level on ease and vividness of mental imagery. The regression model with the experiment and follow-up survey data (n = 128) showed a significant relationship between ease of mental imagery and actual snacking behavior after controlling for habit strength. The findings suggest that adding a narrative message to the II intervention can be useful, especially when the intervention involves mental imagery and invites less motivated people.

Notes

¹ Although the present study did not involve a strict manipulation checking process, we content-analyzed participants’ implementation plans and deleted cases that did not follow the instruction. For example, four cases in the message-aided condition were deleted as they came up with their own implementation plan instead of resembling the healthy snacking stories provided by the researcher.

² The first pilot test was conducted to identify situations associated with college students’ snack consumption behaviors and healthy snacks that they are likely to try in future. The second pilot test was then conducted to test feasibility and vividness of narrative stories developed. Four stories with the highest scores were selected for the main experiment. More information including actual scenarios is available from the corresponding author.

³ Participants were asked to treat one portion as equal to the size of a tennis ball.

⁴ More information about the snack category is available from the corresponding author.

⁵ There was no significant difference in the amount of healthful and unhealthful snack consumption between the high motivation group and low motivation group (t _high = .141, p _high = .89; t _low = -.141, p _low = .89).

⁶ VIP stands for Variable Importance in the Projection.