If you’ve ever seen the television show Gilmore Girls, you know that Rory Gilmore is a textbook overachiever. She sets her sights on Harvard at a young age, she finishes all of her weekend homework by Saturday so that she can devote Sundays to extra credit, and she has every detail of her life planned out for the next five decades. Why are some people overachievers and/or go-getters willing to work hard to reap future rewards, while others are perfectly content to settle and slack off?
According to a recent study, the degree of motivation people exhibit may be determined by levels of dopamine in the brain.
Dopamine is a neurotransmitter that has several different functions. It regulates movement and emotional responses; it’s also linked with the reward system of the brain. When dopamine is released in certain regions of the brain, people experience pleasure and satisfaction. These feelings of enjoyment motivate people to seek out and perform certain activities. Eating food releases dopamine, as does using technology.
While dopamine’s role in the brain’s pleasure and reward system is well established, this new study shows it may play a role in people’s motivation and work ethic as well.
The study sets out to determine how hard people were willing to work for a monetary reward. It looked at 25 participants ranging in age from 18 to 29. The participants were able to choose between playing an easy button-pushing task in which they would earn $1 or a more difficult task where they could earn up to $4. Some people chose to work harder and perform the difficult task for the bigger reward, while others stuck to the easy task and reaped a smaller reward.
Why did some opt for the more difficult task? The answer lies in the brain. Researchers imaged the brains of the participants and found that those who selected the harder task had high dopamine levels in two areas of the brain: the striatum and the ventromedial prefrontal cortex, both of which are linked to reward and motivation. This was expected.
What was not expected was the discovery that those who opted for the less difficult task had a higher release of dopamine in the anterior insula, a region of the brain involved with emotion, meaning that they were focused more intently on the cost of the exercise (incessant button pushing and consequent pinky-finger pain) than the rewards.
Both sets of participants had high dopamine levels—albeit in different brain areas. This finding shows that dopamine can have opposing effects in different brain regions; simply put, dopamine does different things in different parts of the brain.
The implications of this study go far beyond explaining the factors behind individual motivation and drive: the opposing effects of dopamine complicate the issue of medications used to treat depression, ADHD, and schizophrenia. The prevailing assumption is that these drugs, which alter dopamine, impact brain regions in the same way, but as this study shows, dopamine does not have a standard, uniform effect.
The results of the study may provide valuable information that can be used to improve the treatment of mental health disorders. It also may help establish an objective method for diagnosing problems such as depression, ADHD, or schizophrenia.
Co-author of the study, David Zald, PhD, remarked, “Right now our diagnoses for these disorders is often fuzzy and based on subjective self-report of symptoms. Imagine how valuable it would be if we had an objective test that could tell whether a patient was suffering from a deficit or abnormality in an underlying neural system. With objective measures we could treat the underlying conditions instead of the symptoms.”
Olivia Roat is a reporter for GoStrengths.com