Date of Degree
PhD (Doctor of Philosophy)
First Committee Member
Second Committee Member
Third Committee Member
Fourth Committee Member
My dissertation focuses on changes in health-related behavior in react to information-based intervention. The first chapter analyzes the results of a field experiment to investigate the effects of comparative information on the daily number of steps taken of adults. The second chapter further explores the effects using qualitative analysis. The third chapter intends to offer explanations in the mechanisms of the results from the first chapter.
My first chapter uncovers how patterns in the daily number of steps of adults are affected by information that compares one with unknown peers. I conducted a field experiment that used fitness trackers to collect daily and minute-by-minute data on the total number of steps an individual takes in a day. Participants were randomized into a group that was provided with comparison information and a group that did not receive such information. I examined whether individuals in the two groups behaved differently during and after the intervention period. I find no clear evidence of an aggregate impact of social norms on the daily number of steps taken. However, I find individuals who are not overweight or nor married or cohabiting are more likely to be influenced by social norms. Greater treatment effects are found among individuals whose number of steps that are at the tails of the distribution curve.
My second chapter reports the results of the textual data from the survey in the field experiment. I present dominant themes that emerged from answers to the open-ended essay questions in the survey. The results support that health concern, body image, appearance, psychological factors, peers and friends are major motives for being physically active. For participation in the study specifically, text messages that contain comparative information produced some improvement of the exercise level. However, participants also requested more interactions with peers, additional information provision, rewards for reaching goals. The results imply external incentives play a smaller role in promoting daily number of steps.
In the third chapter, I conduct a survey experimentation to test the effectiveness of informing descriptive social norms and types of text messages in predictions about health-related behaviors. First, I investigate if errors in beliefs about activity levels exist and I find no evidence of over- or under-confidence in one’s own activity levels. Further analysis provide preliminary evidence of negative effects of informedness in predictions about one’s own behavior. However, the intention-to-treat effects of comparative information are unclear. The data provide evidence in favor of the correlation between first-order personal beliefs, not higher-order normative beliefs, in predicting an increase number of steps taken in response to intervention with text messages.
Behavioral economics, Field experiment, Health economics
x, 106 pages
Includes bibliographical references (pages 6-70).
Copyright © 2019 Lianjun Li
Li, Lianjun. "The impacts of social comparison information on physical activity." PhD (Doctor of Philosophy) thesis, University of Iowa, 2019.