Researchers in the US found that when they stopped the primates’ brain cells from receiving dopamine the animals worked harder with better results.
“Like many of us, monkeys normally slack off initially in working toward a distant goal,” said lead scientist Barry Richmond of the National Institute of Mental Health.
But when dopamine was blocked they became ‘extreme workaholics’.
“This was conspicuously out-of-character for these animals. Like people, they tend to procrastinate when they know they will have to do more work before getting a reward,” said Dr Richmond.
“The gene knockdown triggered a remarkable transformation in the simian work ethic.
“They work more efficiently - make fewer errors - as they get closer to being rewarded.”
The scientists used a new genetic technique to block the uptake of dopamine by brain cells.
Dopamine is a chemical which carries messages relating to rewards to the brain.
Seven rhesus monkeys were used in the trial.
When they pushed a lever in response to visual clues on a screen they were rewarded with water.
“Without the dopamine receptor, they consistently stayed on task and made few errors, because they could no longer learn to use visual cues to predict how their work was going to get them a reward,” Dr Richmond said.
But rather than planning to create a future generation of workaholics, Dr Richmond said the new research could be used to study mental illness.
“In this case, it’s worth noting that the ability to associate work with reward is disturbed in mental disorders, including schizophrenia, mood disorders and obsessive-compulsive disorder, so our finding of the pivotal role played by this gene and circuit may be of clinical interest,” he said.
“For example, people who are depressed often feel nothing is worth the work. People with obsessive-compulsive disorder work incessantly; even when they get rewarded they feel they must repeat the task.
“In mania, people will work feverishly for rewards that aren’t worth the trouble to most of us.”
The study was published in the Proceedings of the National Academy of Sciences.