
Switching Tasks
What many people might call “multitasking” may actually be something psychologists call “rapid task-switching.”
And then there’s the cost that comes with task-switching. There’s a delay when you switch from one thing to another, and sometimes a temporary drop in performance.
An hour spent on one thing followed by an hour on another is fine. The task-switching cost is much less than the time you’re spending on each task. But if you’re switching tasks every few minutes, or every few seconds, the cognitive cost of switching from one task to the other interferes with performance.
Calculating the Cost
For some tasks, such as identifying the gender of a face, and then switching to identifying the facial expression, the switch only takes only about 200 milliseconds. But even this small cost can reduce productivity by 40 percent if you try to study while watching a movie.These results, and others like it, come from the field of cognitive psychology, where researchers study volunteers in a controlled laboratory setting, usually doing rapid-response tasks on a computer.
But how well do these findings translate to the real world?
In offices, people get interrupted repeatedly throughout the day. Your work on a budget might be disrupted by a coworker who wants to tell you about their kids.

The cognitive psychologists are doing very controlled laboratory studies, where you’re doing fairly simple tasks with simple stimuli. The task in those experiments often involves simply attending to another aspect of what you’re looking at (such as gender vs. facial expression of faces). But you can see how this is a very different situation from getting a phone call in the middle of writing a report.
Practical Advice
The negative effect of multitasking is real, but it’s particularly problematic because people don’t realize these negative effects are happening. Interruptions and doing many things at once generally make us less productive.The advice is simple: When doing something that requires thinking, don’t do anything else.
To remain focused—but at the same time cover a lot of ground—try structuring your day into half-hour chunks. Work on something different just about every half-hour.
