The Atlantic (Gift Article): The Secret to Success Is Monotasking. “Here’s the frightening part: We gravitate to a customary level of interruption. If you are disrupted by notifications all day, every day, then even if those external triggers magically disappear, you will unconsciously start interrupting yourself to maintain the rhythm of distraction you’re used to. That is why the mere presence of a smartphone on a desk or in a ­pocket—even if it is turned off—has been shown to impair performance on cognitive tests, particularly among people who are more phone dependent.”

Over the next 20 years, Mark studied work activity at large organizations such as Microsoft using increasingly sophisticated tools, including cameras and programs that recorded computer activity. In 2012, she found, office workers were switching tasks every ­75 seconds. By 2022, it was about every ­45 seconds. Multitasking is the act of distracting yourself. It comes with a cost even when tasks feel related, because it requires you to switch the “mental rules of the game,” as the cognitive scientist Daniel Willingham puts it. Even when people are allowed to switch between tasks at their own discretion, the more they switch, the longer everything takes. As Mark has written: “We find that in ­real‑world work, the more switches in attention a person makes, the lower is their end‑­of‑day assessed productivity.”