Using data from a field experiment in Kenya, we document that providing individuals with simple informal savings technologies can substantially increase investment in preventative health and reduce vulnerability to health shocks. Simply providing a safe place to keep money was sufficient to increase health savings by 66 percent. Adding an earmarking feature was only helpful when funds were put toward emergencies, or for individuals that are frequently taxed by friends and relatives. Group-based savings and credit schemes had very large effects.

Coping with Political Instability: Micro Evidence from Kenya's 2007 Election Crisis by Pascaline Dupas and Jonathan Robinson. Published in volume 100, issue 2, pages 120-24 of American Economic Review, May 2010

We model farmers as facing small fixed costs of purchasing fertilizer and assume some are stochastically present biased and not fully sophisticated about this bias. Such farmers may procrastinate, postponing fertilizer purchases until later periods, when they may be too impatient to purchase fertilizer. Consistent with the model, many farmers in Western Kenya fail to take advantage of apparently profitable fertilizer investments, but they do invest in response to small, time-limited discounts on the cost of acquiring fertilizer (free delivery) just after harvest. Calibration suggests that this policy can yield higher welfare than either laissez-faire policies or heavy subsidies.

How High Are Rates of Return to Fertilizer? Evidence from Field Experiments in Kenya by Esther Duflo, Michael Kremer and Jonathan Robinson. Published in volume 98, issue 2, pages 482-88 of American Economic Review, May 2008

Many subjects in lab experiments exhibit small-stakes risk aversion, consistent with loss aversion. Those with greater math skills are less likely to show small-stakes risk aversion. We argue that departures from expected utility maximization may help explain why many firms in developing countries leave high expected return investments unexploited. We show that among a sample of Kenyan shopkeepers, inventories are negatively associated with small-stakes risk aversion and positively associated with math skills.