Gloria Mark, professor in the department of informatics at the University of California, Irvine, says that when people are interrupted, it typically takes 23 minutes and 15 seconds to return to their work, and most people will do two intervening tasks before going back to their original project. This switching leads to a build up of stress, she says, and so little wonder people who have high rates of neuroticism, impulsivity, and are susceptible to stress tend to switch tasks more than others.