Coffee is known to have a `stimulant` effect on work-shy people but evokes opposite result on hard workers, making them slack off, suggests a new study.
The study found that caffeine and other stimulants such as amphetamines don't actually raise motivation levels.
People who are already motivated could well feel the urge to slack off and the only ones who benefit from the drink would be slackers.
"Every day, millions of people use stimulants to wake up, stay alert and increase their productivity - from truckers driving all night to students cramming for exams," the Daily Mail quoted Jay Hosking, a PhD candidate in the University of British Columbia's Department of Psychology, who led the study, as saying.
"These findings suggest that some stimulants may actually have an opposite effect for people who naturally favour the difficult tasks of life that come with greater rewards," Hosking said.
The researchers explored the impacts of stimulants on rats.
With "busy" rats, who were more willing to solve the laboratory puzzles presented to them, coffee and amphetamines made them less active. But with lazier specimens, the opposite was true.
The "slacker" rats that typically avoided challenges worked significantly harder when given amphetamines, while "worker" rats that typically embraced challenges were less motivated by caffeine or amphetamine.
The study was published in the scientific journal Nature's Neuropsychopharmacology.