Dopamine levels influence decision making.

From BBC:

Dopamine, a chemical with a key role in setting people's moods, could have a much wider-ranging impact on their everyday lives, research suggests.

Experiments show that altering levels of the chemical in the brain influences the decisions people make.

One expert said the results showed the relative importance of "gut feeling" over analytical decision making.

The Current Biology study could help understand how expectation of pleasure can go awry, for example in addiction.

It follows previous research by the University College London team, which, using imaging techniques, detected a signal in the brain linked to how much someone enjoyed an experience. They found that signal could in turn predict the choices a person made.

With the suspicion that the signal was dopamine, the researchers set up a study to test how people make complex decisions when their dopamine system has been tampered with.