This article provides a critical discussion of the potential contributions behavioral economics makes to the idea of a Basic Income Guarantee (BIG). Behavioral economics suggests that the consequences of a basic income may be significantly different from the ones predicted by the Standard Economic Model. Three topics from this literature are analyzed and linked to the BIG idea: Prospect Theory, Motivation Crowding Theory, and Conspicuous Consumption. The article argues that a basic income may be efficiency enhancing under some conditions, but at the same time incentives related to positional concerns may increase wasteful expenditure following its implementation.