Dopamine is famous for being the pleasure causing chemical in our brain as it plays a critical role in motivational control, that is in giving our bodies the sensation of pleasure in response to certain stimuli or events. The traditional theory has been that dopamine, released by neurons in the brain when our bodies encounter beneficial or otherwise trained stimuli, helps to reinforce the pathways in the brain that lead to a reward. So, if you eat a good meal or get an unexpected bonus on your paycheck, leading to physiological benefits, your body releases dopamine to reinforce this behavior. This has often been interpreted as dopamine causing pleasure.
Scientists are now considering the role that dopamine plays in our bodies’ response to other stimuli, such as surprising, new, or negative events. Indeed, scientists have discovered that dopamine plays a large role in training us to avoid behavior that isn’t beneficial. For example, one study gave two groups of rats with different amounts of dopamine in their brains a small electric shock and provided means for them to learn how to avoid the shock. The study found that rats with higher amounts of dopamine learned much quicker how to avoid the shock suggesting that dopamine was helping train them to avoid the negative stimulus. This has led scientist to suggest that dopamine may have more to do with governing our expectations and motivating our behavior than causing pleasure.
Scientists stress that such revelations will be helpful in uncovering the roots of problems such as addiction and bad behavior, and ultimately for demonstrating that dopamine, and indeed pleasure itself, are much more complicated than we first thought.