Jonah Lehrer profiles the neurotransmitter:
The caricature of dopamine as the chemical of hedonism and pleasure - it's what drives us to enjoy sex, drugs and rock and roll - was always mostly misleading. While dopamine does predict the arrival of rewards, the neurotransmitter is much more important that. Many dopamine researchers, for instance, refer to the chemical as our "neural currency," since it allows us to quickly assign a value to the multitudes of things and ideas in the outside world. (In other words, dopamine is the price tag of sensory information.) When we see something we want - and it doesn't matter if it's a chocolate cupcake or a glass of water - the mere sight of the object triggers a wave of emotional desire, which motivates us to act. (Emotion and motivation share the same Latin root, movere, which means "to move.") The world is full of possibilities, and it is our dopaminergic feelings that help us choose between them.