The use of mobile phones in poverty reduction and development has ignited much interest over the past decade. To take advantage of the rapid expansion of mobile phones in developing countries, businesses, government agencies and non-governmental organisations are increasingly turning their...

This paper asks whether population growth is conducive to the sustainability of cooperation. A simple model is developed in which farmers who live around a circular lake engage in trade with their adjacent neighbors. The payoffs from this activity are governed by a prisoner’s dilemma “rule...