emotion

Emotion is the brain's strategy to adapt to uncertainties encountered in the interaction with the environment. The behavior of the dopaminergic system, which responds to the contingencies (co-existence of predictable and unpredictable events) is one of the best examples.

References
Onzo, A. and Mogi, K. (2005) Dynamics of betting behavior under flat reward condition. International Journal of Neural Systems 15, 93-99.