UC Berkeley

This dissertation is comprised of three essays at the intersection of Development and Psychology and Economics. The essays jointly explore how health behavior is influenced by social image concerns. Starting from the empirical fact that individuals care about how they are perceived by others, the essays connect economic theory to real-world settings to experimentally test the strength of these preferences. The objective is to shed light on potential mechanisms that increase the demand for preventative health.

In my first chapter, I introduce Bénabou and Tirole’s theory of social signaling that motivates the randomized field experiments discussed in Chapters 2 and 3. I discuss how the theoretical framework maps into a static and dynamic decision making problem. For the static setting, I consider agents’ decision to take up a one time deworming treatment. For the dynamic setting, I look at agents’ sequential decision making when taking their children for different vaccinations across multiple periods. I investigate how take-up decisions change in the presence of social signaling concerns (i) as actions become more visible, (ii) as the cost of actions increases and (iii) as uncertainty in the form of future cost shocks become relevant. Using simulations I contrast the qualitative predictions of social signaling with and without uncertainty. In a first finding, I show that visibility in actions increases the probability of take up, conditional on individuals perceiving the action as socially desirable and valuing others’ perception of their type. Secondly, I show that the effect of cost increases on take-up decisions can be amplified or mitigated as reputational returns change. Third, incorporating uncertainty into decision making leads to less strong bunching predictions at signaling thresholds and more continuous shifts in the distribution of actions. Fourth, I lay out testable predictions for the underlying mechanisms of the model and its assumptions. Chapters 2 and 3 empirically test the qualitative predictions laid out in this first chapter.

In my second chapter, coauthor Karim Naguib and I ask the question: Can social image concerns motivate adults to internalize health externalities? In collaboration with the Kenyan Government, we implement a new community program that offers free deworming treatment to 200,000 adults and emphasizes the public good aspect of deworming. Importantly, we randomize the introduction of two types of social signals in the form of colorful bracelets and ink applied to the thumb. The bracelets and ink allow adults to signal that they contributed to protecting their community from worms. To separate social signaling preferences from reminder and learning effects, we offer free text messages to a random sub- set of adults. Further, we exogenously vary the travel distance to treatment locations. We find that (1) bracelets as signals increase deworming take-up by 24 percent, outperforming a material incentive; (2) the effects are not due to pure reminder or learning effects; (3) there is no detectable effect for the ink signal, which we attribute to its lower visibility; (4) adults are highly sensitive to distance and both signaling treatments have a larger impact on take-up at far distances. The latter finding is consistent with the theoretical prediction that signaling returns increase as signals become more informative. Detailed survey data on first and second-order beliefs shed light on the underlying mechanism: signals reduce information asymmetries, and adults are more likely to think that others have information about their deworming decision.

In my third chapter, I investigate social signaling in the context of childhood immunization in Sierra Leone. Despite high initial vaccine take-up, many parents do not complete the five immunizations that are required in a child’s first year of life. I introduce a durable signal - in the form of differently colored bracelets - which children receive upon vaccination, and implement a 22-month-long experiment in 120 public clinics. Informed by theory, the experimental design separately identifies social signaling from leading alternative mechanisms. In a first main finding, I show that individuals use signals to learn about others’ actions. Second, I find that the impact of signals varies significantly with the social desirability of the action. In particular, the signal has a weak effect when linked to a vaccine with low perceived benefits and a large, positive effect when linked to a vaccine with high perceived benefits. Of substantive policy importance, signals increase timely and complete vaccination at a cost of approximately 1 USD per child, with effects persisting 12 months after the roll out. Finally, I structurally estimate a dynamic discrete-choice model to quantify the value of social signaling.