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There is no denying that some people possess a certain joie du travail. They are not only at work early on a Monday morning, but they’ve brewed a pot of coffee and have solved the copy machines problems all before the boss has arrived. But they don’t stop there…. They are ready to tackle all the major projects, make all the necessary phone calls, and shoot off all the e-mails without pausing for a second to consider the rewards or lack thereof for their extra work. Why is it that some individuals have an unstoppable drive and unwavering motivation? A new study published May 2 in the Journal of Neuroscience suggests a chemical explanation for the go-getter – dopamine.
How did they do the study?
A team of scientists at Vanderbilt University studied 25 healthy volunteers between the ages 18-29 to determine their willingness to work for a cash reward. First the participants were asked to choose a button-pushing task ranging from easy to difficult. An easy task equated to a reward of $1 while the harder tasks earned up to $4. After making their task selections, they were given the reward probability of high, medium, or low. Participants then performed each task for about 30 seconds over the course of 20 minutes. Using the positron emission tomography (PET scan) brain mapping technique, the researchers recorded brain activity associated with the willingness to work for a reward.
What did they find?
The researchers found that those willing to work hard for a reward had higher amounts of dopamine in the striatum and ventromedial prefrontal cortex area of the brain, known for its role in reward and motivation. Conversely, those less willing to work hard showed high levels of dopamine in the anterior insula area of the brain—the part that plays a role in risk perception and emotion. While the effects of dopamine on the perception of reward motivation was known, the amount of dopamine in the anterior insula came as a surprise. This new finding reveals how dopamine can determine differences among people in the drive for reward and suggests that higher levels of dopamine in this area of the brain is tied to a lower desire to work, despite a potential monetary reward.
So what’s the significance?
The unexpected finding indicates that not only does the presence of dopamine matter in terms of how motivated someone is, but also so does where the dopamine is in the brain. This could complicate the current use of psychotropic medications that are designed to affect dopamine levels for the treatment of ADD, depression, and schizophrenia. The effectiveness of these medications is now called into question, since they merely increase dopamine levels without targeting where in the brain the chemical would be most effective. Ultimately, this research could lead to more effective treatments because it illustrates the need to guide dopamine to specific areas of the brain.