Some of us have a continuous drive to work hard and to earn money, others are slackers. Why? According to new research, there’s a biological explanation. Go-getter or slacker? It may depend on the brain chemical dopamine.
”Past studies in rats have shown that dopamine is crucial for reward motivation. But this study provides new information about how dopamine determines individual differences in the behaviour of human reward-seekers,” said lead author Micheal Treadway of the Vanderbilt University.
Treadway and his team asked participants to perform a variety of button-pushing tasks, to determine their willingness to work for a monetary reward. Positron emission tomography (PET) brain scans were used to measure dopamine activity in different parts of the brain.
The researchers found that people willing to work hard to earn rewards had higher release of dopamine – a “feel-good” neurotransmitter – in areas of the brain known to play an important role in reward and motivation: the striatum and ventromedial prefrontal cortex. People who weren’t keen to work, however, had higher levels of dopamine in part of the brain that plays a role in emotion and risk perception, called the anterior insula.
The researchers were surprised to find that those with increased dopamine activity in the insula were the least likely to expend effort on the task. “These results show for the first time that increased dopamine in the insula is associated with decreased motivation,” said Treadway.
The fact that dopamine has opposite effects in different brain regions complicates the picture for treatments of conditions such as attention-deficit disorder, depression and schizophrenia.
Photo: slworking2 / Flickr