Bài đọc 4
Ask people whether they are good at multitasking and many will say yes, often with a certain pride. In a world of constant notifications, the ability to answer emails during a meeting while keeping an eye on the news seems not just useful but essential. Yet decades of research suggest that what most of us call multitasking is something rather different, and considerably less efficient, than we imagine.
For most tasks that require conscious attention, the brain does not truly work on two things at once. Instead, it switches rapidly between them. Each switch carries a cost. In a series of experiments published in 2001, the psychologists Joshua Rubinstein, David Meyer and Jeffrey Evans asked volunteers to move between different kinds of problems, such as solving sums and sorting shapes. Every time participants changed task, they lost time, and the losses grew larger as the tasks became more complex. A fraction of a second here and there may sound trivial, but across a working day of constant interruptions, the researchers argued, it could add up to a substantial share of productive time.
There are, admittedly, exceptions. Activities that have become largely automatic, such as walking, or folding laundry for someone who has done it thousands of times, can be combined with conversation without much difficulty. The problem arises when two activities compete for the same mental resources, as when we try to write a report while following a phone call.
Perhaps the most counterintuitive findings concern people who multitask the most. In a widely cited study from 2009, researchers at Stanford University compared students who reported using many forms of media at the same time with students who rarely did so. One might expect the heavy multitaskers to have become experts through practice. The opposite appeared to be true: they performed worse on tests measuring the ability to ignore irrelevant information, and, surprisingly, they were also slower at switching between tasks.
The study could not show whether heavy multitasking causes these difficulties or whether people who are easily distracted are simply drawn to it, and later research has produced mixed results. Nevertheless, the broader conclusion has held up well: our capacity for attention is limited, and dividing it has a price.
None of this means that we should abandon the modern workplace and retreat to a cabin in the woods. It does, however, suggest some modest changes. Grouping similar tasks together, turning off notifications for periods of focused work and treating attention as a resource to be managed, rather than an endless supply, may achieve more than any attempt to do everything at once. The irony is that those who are proudest of their multitasking may be the ones who would benefit most from doing less of it.