Why do we take risks?  Why do we gamble?  A brilliant piece of research reported in this week's Science describes a newly found population of dopaminergic neurons that appear to reward uncertainty; the activity of these neurons increases as the delivery of reward becomes less certain. 

The authors propose that the activation of these dopamine neurons by uncertainty mobilizes attention, motivates risk-seeking behavior, and promotes learning about relationships between stimuli and consequences. 

This new information is sure to add another piece of the puzzle for the decision theorists who continue to strive to integrate emotional and cognitive influences on choice and human behavior, a truly important and complex endeavour.