Olivia Farrell, founder of Arkansas Business Publishing Group, has often warned about the "friction" that is an unavoidable part of multitasking. No matter how many skills you have or how many tasks you can master, there is a drag — a loss of time and productivity — when you switch between tasks. And the more often you switch, the more friction you create and more productivity that is lost.

Farrell may have made this conclusion based on her intuition or her skills of observation, both of which contributed to her status as a member of both the University of Arkansas' Business Hall of Fame and the Arkansas Women's Hall of Fame. But scientific studies say she's dead-on.

In some cases, multitasking can be low-stress and deliberate: listening to a podcast while driving or watching TV while on a treadmill. But even in these happiness-enhancing examples, it's easy to see the limits of multitasking. Listening to a podcast while driving is one thing; searching your phone app for another podcast to listen to while behind the wheel is quite another. Multitasking can easily morph into distraction, and you despise other drivers you suspect of multitasking. 

In other cases, multitasking does not refer to doing two or more things simultaneously. It can more accurately be described as task switching, the term used by engineering researchers from Northwestern State University of Louisiana and counterparts at King Saud University in Saudi Arabia. This refers to "moving from one task to another in a planned manner within an assigned period." 

You can probably think of a dozen examples: seating guests at a restaurant and then taking their drink orders; cycling loads of laundry from washer to dryer while working from home; taking a lunch break at the same time every day, even if it means finishing a particular task afterward. 

The important word in task switching is planned. Planned multitasking creates a certain amount of friction, but planning for a change in tasks is also, subconsciously or not, planning for the friction that comes with it. If you know you are going to be entirely too focused on work, you don't start the laundry until afterward.

The Louisiana and Saudi researchers noted that managing task-switching in the workplace has been studied for at least a century, since the first efficiency experts began striking fear into the hearts of workers. The earliest studies sought to maximize productivity by determining the most efficient order to perform distinct tasks on a production line, while recent studies have considered more individualized approaches to the task-switching necessary in modern workplaces. 

Then there is the third category of multitasking, the dreaded task interruption. Yes, an interruption can occasionally be welcome, especially when the primary task is arduous or frustrating. But the friction of an interruption is the most taxing for all the reasons it's different from task switching. "Unlike task switching, interruptions force a person to move from one task to another in an unplanned manner," the researchers wrote.

They identified both external and internal interruptions, giving alerts and notifications as common examples of the former, which have, of course, multiplied with our use of electronic communications devices. Edward R. Sykes, writing for the International Journal of Information Management in 2010, pointed out that humans "are generally very good at negotiating when is an appropriate time to interrupt another person…. Unfortunately, computers and computer systems … are not as sophisticated as people's reasoning abilities."

The Louisiana and Saudi researchers said internal interruptions are "related to internal decisions to stop an ongoing task to attend another, due to personal thought processes or choices, also called self-interruption." The language may be dryly academic, but the situation is familiar: Your own brain can pull you off-task as easily as any phone call or text message. (A considerable amount of that has happened during the writing of this article.) 

From his research, Sykes concluded that:

Multitasking is less efficient. He compared a multitasking person with a computer in which multiple apps are running at the same time, putting a drain on the central processing unit. Except, "for a human to switch tasks is even more involved and complicated" because "the mental requirement and sometimes physical requirement can be very high."

Multitasking is more complicated. Changing tasks requires "a degree of overhead in terms of management and mental awareness." Not only do multitaskers feel additional stress, but they are more likely to make errors.

Multitasking can be self-directed. Sometimes multitasking, whether planned task switching or task interruption, is imposed on us. We have no choice. But in many cases, "the user has a choice to switch a task or to remain focused on the current task."

Sykes compiled research from multiple sources and included several practical tools for avoiding the friction of multitasking, starting with recognizing the costs — financial and psychological — associated with changing tasks.

• When task switching can be planned, do it. This is especially important in "high cognitive load tasks," the work that requires close attention and concentration. You may already do this intuitively, scheduling a demanding task when you expect to have a large block of uninterrupted time.

• Wherever possible, reduce the potential for office distractions. "For example," Sykes wrote, "a cluttered desk with stacks of paper or walls with numerous posters should be avoided."

• A system for ranking the significance of notifications should be adopted. For instance, you might filter out emails from all but the most important senders and deal with them at a set time.

• Take steps to minimize office noise, especially voices since conversations can be especially distracting. Individual offices are ideal, but artificial white noise can also be helpful. 


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