Even tiny interruptions can derail your train of thought and increase mistakes, new research shows. Short interruptions—such as the few seconds it takes to silence that buzzing smart phone—have a surprisingly large effect on one’s ability to accurately complete a task, according to new research.
The study, in which 300 people performed a sequence-based procedure on a computer, found that interruptions of about three seconds doubled the error rate.
Brief interruptions are ubiquitous in today’s society, from text messages to a work colleague poking his head in the door and interrupting an important conversation. But the ensuing errors can be disastrous for professionals such as airplane mechanics and emergency room doctors, says Erik Altmann, lead researcher on the study and associate professor of psychology at Michigan State University.
“What this means is that our health and safety is, on some level, contingent on whether the people looking after it have been interrupted,” says Altmann.
The study, published in Journal of Experimental Psychology: General, is one of the first to examine brief interruptions of relatively difficult tasks.
Study participants were asked to perform a series of tasks in order, such as identifying with a keystroke whether a letter was closer to the start or the end of the alphabet. Even without interruptions a small number of errors in sequence were made.
Sometimes participants were interrupted and told to type two letters—which took 2.8 seconds—before returning to the task. When this happened, they were twice as likely to mess up the sequence.
Altmann says he was surprised that such short interruptions had a large effect. The interruptions lasted no longer than each step of the main task, he noted, so the time factor likely wasn’t the cause of the errors.
“So why did the error rate go up?” Altmann asks. “The answer is that the participants had to shift their attention from one task to another. Even momentary interruptions can seem jarring when they occur during a process that takes considerable thought.”
One potential solution, particularly when errors would be costly, is to design an environment that protects against interruptions. “So before you enter this critical phase: All cell phones off at the very least,” Altmann says.
Gregory Trafton of the Naval Research Laboratory and Zach Hambrick of Michigan State are co-authors of the study, which was funded by the US Navy’s Office of Naval Research.