There exists ample evidence documenting the role of a "placebo" (often a sugar pill) in improving objective outcomes in medical trials, including a smaller literature identifying beliefs as the channel through which this effect operates (Malani, 2006; Kamenica et al, 2013; Benedetti et al, 2005). In this paper I plan to test whether a congruent effect exists in the social sciences. That is, do recipients of government interventions or research treatments experience better outcomes if they have more positive beliefs about the efficacy of the treatment they are receiving? To identify the role of beliefs in determining treatment efficacy, I am partnering with a non-profit organization, Wholesome Wave, to run an experiment in which I measure the impact of exogenous changes in beliefs. Wholesome Wave provides fruit and vegetable gift cards to low-income individuals in the United States to encourage healthy eating. I plan to introduce an intervention in a new Wholesome Wave program in Corpus Christi, TX in which participants will be asked to set a goal for the amount they want to spend on fruits and vegetables. I will randomly assign individuals to receive either optimistic or no information about the efficacy of goal setting. My primary outcome of interest is the impact of this exogenous variation in beliefs on subsequent goal achievement, measured through card expenditures. In the event that beliefs do indeed affect treatment efficacy, such a finding would allow researchers to better understand the generalizability of observed treatment effects and also provide a tool for policymakers looking for a cost-effective means of improving intervention outcomes.