This paper by Eric Bonsang, Thomas Dohmen, Arnaud Dupuy and Andries de Grip (Maastricht University, ROA) reviews the psychological, medical, and economic literature on the causes and consequences of cognitive aging. From the evidence provided in the literature on cognitive aging and the relationship between age, cognition, training, and productivity they derive a way to better frame the limits within which potential policy interventions that aim to improve the employability of aging workers might work and hence derive better policy interventions that improve the development and utilization of cognitive resources among aging workers.