Most supermarket workers claim that mistakes are made because they are bored, often leading them to drink at the end of their shift, according to a new study.
The repetitive and routine nature of their work often causes them to lose concentration and daydream, research by an occupational psychologist found.
Dr Sandi Mann, of the University of Central Lancashire, suggested that employers should consider screening job applicants to see if they were prone to boredom before offering them jobs which involved a high level of routine.
A survey of more than 100 employees of a leading supermarket chain, including drivers and check-out staff, found that two-thirds believed the boredom of their job was likely to lead them to make mistakes.
"These mistakes could be dangerous or could be costing the customer money if they are made in pricing or at the till," Dr Mann said at the British Psychological Society's occupational psychology conference in Stratford upon Avon.
One in four supermarket workers questioned said they were likely to turn to drink to relieve boredom, while almost half said being bored caused them to become stressed.
"It looks as though boredom is the new stress," said Dr Mann, adding that some people had a "boredom prone" personality and were more likely to experience chronic boredom in the workplace.