By Daniel J. Levitin
Our cell phones have become Swiss Army knife–like appliances that include a dictionary, calculator, Web browser, e-mail client, Game Boy, appointment calendar, voice recorder, guitar tuner, weather forecaster, GPS, texter, tweeter, Facebook updater, and flashlight.
They’re more powerful and do more things than the most advanced computer at IBM corporate headquarters thirty years ago. And we use them all the time, part of a twenty-first-century mania for cramming everything we do into every single spare moment of downtime.
We text while we’re walking across the street, catch up on e-mail while standing in line, and while having lunch with friends, we surreptitiously check to see what our other friends are doing.
At the kitchen counter, cozy and secure in our domicile, we write our shopping lists on smartphones while we are listening to that wonderfully informative podcast on urban beekeeping.
When people think they’re multi-tasking, they’re actually just switching from one task to another very rapidly. And every time they do, there’s a cognitive cost in doing so.
So we’re not actually keeping a lot of balls in the air like an expert juggler; we’re more like a bad amateur plate spinner, frantically switching from one task to another, ignoring the one that is not right in front of us but worried it will come crashing down any minute. Even though we think we’re getting a lot done, ironically, multitasking makes us demonstrably less efficient.
Multitasking creates a dopamine-addiction feedback loop, effectively rewarding the brain for losing focus and for constantly searching for external stimulation. To make matters worse, the prefrontal cortex has a novelty bias, meaning that its attention can be easily hijacked by something new—the proverbial shiny objects we use to entice infants, puppies, and kittens.
The irony here for those of us who are trying to focus amid competing activities is clear: The very brain region we need to rely on for staying on task is easily distracted. We answer the phone, look up something on the Internet, check our e-mail, send an SMS, and each of these things tweaks the novelty-seeking, reward-seeking centers of the brain, causing a burst of endogenous opioids (no wonder it feels so good!), all to the detriment of our staying on task. It is the ultimate empty-caloried brain candy.
Instead of reaping the big rewards that come from sustained, focused effort, we instead reap empty rewards from completing a thousand little sugarcoated tasks.
There is an implicit expectation that you should be able to reach someone when it is convenient for you, regardless of whether it is convenient for them. This expectation is so ingrained that people in meetings routinely answer their cell phones to say, “I’m sorry, I can’t talk now, I’m in a meeting.”
Just a decade or two ago, those same people would have let a landline on their desk go unanswered during a meeting, so different were the expectations for reachability.
Just having the opportunity to multitask is detrimental to cognitive performance.
Glenn Wilson of Gresham College, London, calls it infomania. His research found that being in a situation where you are trying toconcentrate on a task, and an e-mail is sitting unread in your inbox, can reduce your effective IQ by 10 points.
Without the distraction of TV, the information goes into the hippocampus, where it is organized and categorized in a variety of ways, making it easier to retrieve it. MIT’s Earl Miller adds, “People can’t do [multitasking] very well, and when they say they can, they’re deluding themselves.” And itturns out the brain is very good at this deluding business.
Then there are the metabolic costs of switching itself. And the kind of rapid, continual shifting we do with multitasking causes the brain to burn through fuel so quickly that we feel exhausted and disoriented after even a short time. We’ve literally depleted the nutrients in our brain.
This leads to compromises in both cognitive and physical performance. Among other things, repeated task switching leads to anxiety, which raises levels of the stress hormone cortisol in the brain, which in turn can lead to aggressive and impulsive behaviors. By contrast, staying on task is controlled by the anterior cingulate and the striatum, and once we engage the central executive mode, staying in that state uses less energy than multitasking and actually reduces the brain’s need for glucose.
To make matters worse, lots of multitasking requires decision-making: Do I answer this text message or ignore it? How do I respond to this? How do I file this e-mail? Do I continue what I’m working on now or take a break? It turns out that decision-making is also very hard on your neural resources and that little decisions appear to take up as much energy as big ones. One of the first things we lose is impulse control.
This rapidly spirals into a depleted state in which, after making lots of insignificant decisions, we can end up making truly bad decisions about something important. Why would anyone want to add to their daily weight of information processing by trying to multitask?