Multitasking, What It is and Isn’t
The premise of multitasking has been around for decades. It’s a phrase we attribute to ourselves more and more with the advancement of technology. But, researchers are skeptical of any gain in productivity through split attention. There are countless tricks and delusions the brain plays on itself, and the appearance of multitasking is likely one of them.
We discuss our multitasking capability when we’re set on doing many things at once. Some of us believe we’re not cut out for it, others that they have a natural gift for accomplishing a lot at once. But decades of research says this isn’t exactly right. What we view as multitasking is actually the brain switching rapidly between streams of information. This gives the appearance we’re attending to two things at once, but that’s not accurate.
Cost Switching is the unconscious ability that allows us to shift from one task to another. It’s an evolutionary milestone that may attribute to humanities dominant rise. It allows us to change environments and adapt to new situations at phenomenal speeds. But, it’s not foolproof. Switching incurs cognitive costs that make it much less desirable for productive work and deep focus.
While we can move between two tasks quickly, it comes at the cost of productivity. Every time we refocus our brain has to reorient. It has to shift goals, track new inputs, and reframe context. While we’re able to shift focus in nanoseconds, each switch tacks on extra costs. These little costs add up over time and make it more difficult to get into the state of flow that characterizes sustained focus.
Similar cognitive actions require the same brains areas to function. This is the exact demand we make during multitasking. Our cognitive power starts to buckle. It can’t call on the same resource simultaneously, it must prioritize one before the other. But our brain has to work through several of these changes for each switch. And that demand adds up.
You can’t listen to two conversations at once, or respond through the phone and email at the same time. Just as you can’t listen to a lecture while notifications ring off on your phone. They all pull from the same communication base in the brain. Even seemingly different tasks compete for similar resources like decision making and self-control.
The only exception to this is for tasks ingrained in our subconscious. They take little mental activation to continue processing. When we talk or sing while driving, we’re demonstrating true multitasking. Though it is possible to be over occupied and fail to react in time. Only in ideal conditions are these activites safe enough to be better than focusing on a single action.
Media Multitaskers Suffer Most
In 2009, the Stanford Communication Lab conducted a series of experiments on multitasking. One hundred students went through a series of tests examining their cognitive ability. The research, led by Clifford Nass, Eyal Ophir, and Anthony Wagner, demonstrated alarming results for heavy media users.
According to the study high media multitaskers (HMM) suffer most from their media use. HMMs are worse at blocking out environmental distractions than low media multitaskers. Almost habitually, they absorb irrelevant information. HMMs were “suckers for irrelevancy”, Nass says.
Each new piece of information interrupts flow. Because they can’t block these interruptions they face a cognitive decline. And, that decline reduces the resources essential for selective-sustained focus.
In another experiment, participants held onto mental representations longer than instructed. Each participant had a string of letters shown to them. There task was to mark when a letter repeated, but only up to a certain extent. HMMs failed to discard irrelevant letters resulting in incorrect duplicate counts. As the amount of letters increased HMMs did worse.
Ophir characterized these results by saying, “The high multitaskers are always drawing from all the information in front of them. They can’t keep things separate in their minds.”
Not only were HMMs worse at blocking information from coming in, once they had it they couldn’t let it go.
The researchers hoped they’d see gains for HMMs in task switching. Again, they were let down. When given two sets of instructions and asked to change their focus at intervals they took longer to perform the task with no gain in accuracy. The studies authors attributed their declines to their inability to filter one set of rules for another.
At no point did heavy media multitasking prove useful to participants. It’s possible the tests didn’t measure every conceivable benefit. But it seems just as likely that there are no benefits to heavy media use. At least from my experience.
The Impact of Task Switching
To switch tasks the brain must make two distinct transitions . First it needs to shift goal orientation from one task to the other, then change the set of rules applied to the new task.
We do this frequently as we complete tasks, like cleaning your room then doing the laundry. And the switch is fast, done in several-tenths of a second. But, when you move between two objectives each switch carries those same burdens. As they add up your efficiency starts do decrease.
And, as demonstrated by Nass and his colleagues, the longer this goes on the worse the burden becomes. Instead of getting used to mental switches the cost compounds decreasing performance over time. Those declines even seem to extend to work you do in the future. Falsely believing that you’re able to multitask craters any hopes for true productivity.
Multitasking can certainly feel like a better use of time. After all knocking out two assignments at once feels better than one, but it’s likely you’d complete them more effectively one by one. David Meyer, who’s done significant research into multitasking, believes that, “mental blocks created by shifting tasks can cost as much as 40 percent of someone’s productivity time.” Even a tenth of that estimate is a startling. When you compound those effects throughout a month of year, the wasted time is staggering.
One Task at a Time
The myth of multitasking is pervasive and belief in it is incredibly tempting. As new technology allows us to do more in the moment it’s hard to resist the lure. After all, we experience no obvious drawback from working on everything at once. It feels effective, and that feeling is all that’s important.
But decades of research should have us rethink this belief. We can get more done and do it better, if we shift to a single stream of tasks.
Media Multitaskers Study – http://www.pnas.org/content/106/37/15583.short
Multitasking Undermines Efficiency – http://www.apa.org/monitor/oct01/multitask.aspx