Can Teens Really Do It All?

Editor’s Note: The author would like to thank her colleague Jennifer Brakeman with whom she collaborated extensively on this article.

We hear it in our classes all the time: students tell us that they can handle Instant Messaging, iTunes, and cell-phone calls and texts while they do their homework, even as they complain about the eight hours it takes them to get the work done. Many adults as well as young people are so addicted to their electronic devices that they are sure that they can text while driving, listen in class while tapping to the beat, and so on, even though cell-phone-related traffic fatalities have risen dramatically and attention to learning has declined. Daniel (not his real name), for example, is an energetic, smart, high school junior at the independent school where I teach. He was a student in my AP U.S. History class recently. We were talking about study habits, distractions, and time spent doing homework one day, and Daniel excitedly said, “I have to listen to rock and roll on my iPod while I’m studying! It’s the only way I can focus!’” Nothing could convince Daniel that the music he listened to as “background” was interfering with his learning. Yet, his understanding of the material lacked depth, and his grades showed it.

Many adults and students today think of themselves as excellent multitaskers — switching from task to task or from task to play in a nanosecond. Yet the pings and tweets our devices emit interrupt us in ways that are more problematic than we think. One of the powerful myths in our culture today is that multitasking is efficient for work or for learning. Research, however, tells a different story. Among adults who spend time multitasking at work or home, more and more people report having difficulty concentrating on a single complex task for an extended period of time. More people, in fact, wonder if their memories are eroding. And more people report having difficulty actually reading a book or a long article online.

The costs of media multitasking are considerable. They include a decrease in executive function (such as the ability to prioritize tasks and figure out what information is most valuable), a decrease in the ability to focus on complex tasks, a decrease in long-term memory, and an increase in stress. When we jump from task to task, quickly scan for information, and shift constantly between work and play, we neither learn things in depth nor retain long-term memories about what we have learned, at least not in a way that we do when we single task. And when we learn while multitasking, we are less able to work creatively with what we know, to problem solve “outside the box.”

Understanding the neurological and psychological bases for these assertions, which are backed by an already substantial and ever-increasing body of research, should help us to take appropriate action in the school and home setting. Research is now showing us that some popular beliefs, such as the notion that multitasking is efficient, or that so-called “digital natives” have developed brains that are wired for multitasking, or that multitasking actually means doing more than one thing simultaneously, are largely misguided. It is also showing us that adolescents are actually less equipped to manage multitasking than adults are, in spite of what they tell us and what we seem to observe in terms of their facility with computers, cell phones, and online worlds.

Importantly, when it comes to education, this is a BOTH-AND conversation. We need to — and can — teach the skills that are necessary to manage large amounts of information: an imperative in the information-rich environment in which we live. We also need to — and can — cultivate the single-focus skills that are necessary for deep learning, creative thinking, and problem solving moving forward. If schools and families fail to take action by applying this research to making better choices and developing better practices to manage the information- and distraction-rich world that we inhabit, our failure to do so will be to the detriment of young people in our care.

Learning, Memory, and Executive Function

It is helpful to understand some basic brain structure and function in order to appreciate the impact of rapid information processing and media multitasking on the brain.

In short, one could say that everything that involves consciousness also involves the cerebral cortex, the outside “peel” of the brain. Everything we experience involves this “peel,” but not everything we experience is remembered, and memory is highly individualized. In understanding memories, think of short-term memory, working memory, and long-term memory (all located in different parts of the cerebral cortex) as having different jobs that are dynamically intertwined. What happens in short-term and working memory dictates what ultimately gets lodged in long-term memory, and what we know is what resides in our long-term memory. It is what is important to us, what we care about, what we have repeatedly done (our habits). It is what sticks with us from our education. It’s not just book learning, but also social-emotional knowing and physico-spatial knowing. Each person’s long-term memory, his or her knowledge of himself or herself and of the world, is unique. It is essentially a person’s identity. We are our memories.

While our long-term memory’s potential is vast, and the information available to us from the outside world is infinite, the human brain quickly goes into cognitive overload when its working memory is overtaxed. Working memory temporarily holds things in your “mind” while other parts of your brain sift through short-term memories, long-term memories, the environment, and so on, looking for connections. Researchers estimate that most people can hold from three to seven things in mind at once, a tiny desktop compared with the expanses of the outside world and of our long-term memory. Once that limit is exceeded, errors occur, things fall off the mind’s desktop: items are forgotten, priority is confused, meaning is lost or fragmented.

As neuroscientist John Medina explains in Brain Rules, memories can be altered or erased and overwritten while they are in the process of becoming long-term memories. When we jump and skitter through the Internet, when we multitask in any way, we create at best fragmented long-term memories — often just vague impressions — because working memory is frequently being overloaded and overwritten. If we bombard our working memory with information from a slew of disconnected sources, it is not able to connect them to one another or to bases in long-term memory. Under too much pressure, new information never becomes part of our long-term memory.

Another dynamic relationship exists among memory, the emotional center of the brain (known as the amygdala), and the brain’s “CEO,” housed in the dorsolateral prefrontal cortex. The latter part of the brain has the uniquely human capabilities that we call the executive functions: our judgment, the ability to set priorities, to choose a “go” versus a “no-go” action, to distinguish junk from useful information. This part of the brain is not fully developed until humans are in their mid to late twenties, and during development it can be more easily overridden by the emotional center of the brain. The brain’s “CEO” looks for connections between information in working memory and long-term memory in order to assess a situation and make decisions. Young people, with more active amygdalas, are more likely to make impulsive decisions than older people, whose “CEO” can override the emotional pull of a situation.

We want young people to create solid mind maps, a process that demands manageable cognitive loads, not environments full of distraction. We want to cultivate skills of good judgment in young people — the ability to set priorities, to distinguish fluff and distraction from useful and important information. We want to cultivate creativity. We want to encourage the development of healthy brains and bodies, which requires sleep, time outdoors, healthy food, and exercise. All of these things require us to understand, among other things, the limited benefits and substantial costs of multitasking with technology.

The Cognitive Costs of Distracting Multitasking

Distracting multitasking, as opposed to the experience of “flow,” is a process of managing interruption1. It is what we experience most of the time, and while it is entertaining, it is neither efficient nor helpful for learning. Most of the time, multitasking means that we are managing and prioritizing multiple unrelated inputs. An example of distracting multitasking is a student listening to popular music on her iPod while she does her Biology homework in a room with the TV on. The whole time, she is repeatedly interrupted by cell phone texts.

People are under the illusion that they literally do things simultaneously when they work and play with multiple interfaces. In fact, however, the brain cannot actually do multiple things simultaneously. Rather, it switches gears, which takes time, reduces accuracy, and inhibits creative thought. In many cases, it is simply less efficient than working on tasks sequentially.

Multitaskers are constantly shifting focus and activities (“I want to do this now instead of that”) and activating different brain rules (“I’m turning off the rules for having a social conversation and turning on the rules for analyzing an Excel spreadsheet”). But each shift takes several tenths of a second — which can add up when people switch back and forth repeatedly between tasks. “Whether [we] toggle between browsing the Web and using other computer programs, talk on cell phones while driving, [we]… are rapidly switching between tasks all the time,” explain researchers from the FAA and the University of Michigan. These researchers studied patterns in the amounts of time lost when people switched repeatedly between two tasks of varying complexity and familiarity, such as solving math problems or classifying geometric objects. The researchers measured subjects’ speed of performance as a function of whether the tasks were familiar or unfamiliar, simple or complex. The measurements revealed that, for all types of tasks, subjects lost time when they had to switch from one task to another, and the amount of lost time increased with the complexity of the tasks.

Given that American cell phone users averaged over 357 text messages per month in 2009, it’s no wonder students who text report spending six, seven, or eight hours doing their homework whereas students who don’t text get the job done in a fraction of the time.

A second impact of multitasking is forgetfulness. Studies of office workers have consistently found that once workers who are multitasking go away from a task, they forget what they were doing before the interruption. They become further distracted by what journalist Clive Thompson calls the “technological equivalent of shiny objects.” In one study, a team of researchers used software on volunteers’ computers that virtually shadowed them all day. On average, they juggled eight different windows at the same time, and they would spend barely 20 seconds looking at one window before flipping to another. When they were interrupted, people literally forgot what they were doing. It typically took them 25 minutes to get back to the original task.

Even more concerning, multitasking to manage distractions adversely affects the brain’s ability to think creatively about what it is learning because it shifts the learning process at the neurological level away from the frontal cortex to a part of the brain that cannot infer. Participants in a 2006 UCLA study revealed this when they performed a simulated weather-prediction activity, which was essentially a memorization and classification exercise. In one round of the experiment, participants learned without any distractions. In a second round, they performed the task while keeping a mental count of high-pitch beeps.

While the distraction of the beeps did not reduce the accuracy of the rote portion of the experiment — people could memorize and classify either way — it did reduce the participants’ “flexible knowledge” about the task during a follow-up session. On the task they learned with the distraction, participants could not extrapolate — that is, could not predict patterns that were not the direct result of memorization. The brain scans performed on participants suggest that the learning actually took place in a different part of the brain, in the striatum instead of the medial temporal lobe. The medial temporal lobe, made up of the amygdala and the hippocampus, is essential to memory formation and learning. The striatum is thought to be a more primitive part of the brain that registers information. This result demonstrates a reduced capacity to make inferences from memorized information. In real life, this means that students like Daniel, who love to listen to rock music while studying, are learning less effectively than students who study without distractions, even though students like Daniel think they are learning, because they can still memorize and classify. This may explain the resistance multitasking students have to being told their learning is less effective when it is constantly interrupted. As the UCLA researchers concluded, however, “learning facts and concepts will be worse if you learn them while you’re distracted.”

Certain types of interruptions, study breaks, and distractions affect memory more than others. This is important to educators who seek to help young people develop study habits — and study breaks — that maximize learning. In a 2006 study at the Brain Imaging and Analysis Center at Duke University, subjects looked at a photo of a face for a few seconds, and then were shown distracting images for a few seconds each. Some distractors were designed to be the visual equivalent of white noise, others were “neutral,” similar in facial content to the original face, but boring in content, and still others were designed to elicit emotions such as fear and anxiety. The subjects were then shown a photo of a face and asked whether they recognized it as the original photo they had seen. When the distractor was scrambled, the recall was good; when the distractor was neutral (boring faces), recall dropped; but when the distractor was faces with emotional content, the recall was worse still. This correlated with MRI evidence showing decreased activation of the part of the brain (DLPFC) where working memory is located, and increased activation of the emotional center of the brain (amygdala).

In practical terms, this means that if the distraction is similar to the task (faces to faces, words to words, etc.), working memory is impaired. And if the distraction is emotionally charged and similar to the task, then the performance declines even more. What do young people favor in their study breaks? Following gossip on Facebook and texting, the more emotionally dramatic the gossip the better — precisely those activities that inhibit the consolidation of memories from their studies, which most of the time are text-based.

Does that mean that people shouldn’t take breaks from their work and studying? On the contrary: the brain does need breaks — and sleep — to consolidate learning and memory. Breaks that rest the tired part of the brain do help strengthen memory traces. But study breaks (distractions) that add more load to the tired part of the brain are time-consuming, stress-provoking, and actually impair learning and memory. Therefore, a student could listen to music as a study break from math or English homework, or get some exercise to increase circulation to the brain. But she should turn off her cell phone and Facebook account until the homework is finished — or better yet, until the weekend.

Why Adolescents Are Less Effective Multitaskers Than Adults

Contrary to popular belief, adolescents are actually less effective multitaskers than adults are. There are two basic reasons for this.

First, the part of the brain that can override impulses is not yet fully developed. The brain continues to physically develop into early adulthood, and the prefrontal cortex, the area of the executive function, is one of the areas that is the last to develop — in young men, this process is not complete until they are in their late 20s. Because their prefrontal cortex is not yet fully developed, adolescents are, among other things, more responsive to emotional stimuli, and less able to override emotional reactions, than adults are. In other words, “just saying no” to an impulse is harder for teenagers than it is for adults because the part of the brain that does that is neither fully developed on a cellular level or well trained on a behavioral level. Many studies have demonstrated this.

The second reason adolescents are less effective multitaskers than adults is that their fluid intelligence is less developed. In recently completed research at the Institute for the Future of the Mind at Oxford University, a group of 18- to 21-year-olds and a group of 35- to 39-year-olds were given 90 seconds to translate images into numbers, using a simple code. The younger group actually did 10 percent better than the adults when not interrupted. But when both groups were interrupted by a phone call, a text message, or an instant message, the older group matched the younger group in speed and accuracy. The reason for this is that the older people think more slowly, but they have a faster fluid intelligence, so they are better able to block out interruptions and choose what to focus on, said one of the lead researchers on the project.

What is “fluid intelligence?” It means that older brains are more efficient than younger brains, because neural pathways that are repeatedly traced are strengthened both through pruning, in which the unused pathways wither away and the repeatedly used ones grow, and through myelination. In myelination, the neural pathways that are repeatedly used develop sheaths, sort of like electrical insulation, that speed the travel of information down those pathways and discourage alternate routes. This is essentially what fluid intelligence is: adults have practiced certain tasks, behaviors, and ways of thinking, and they can easily access these pathways. Adolescents are still developing those pathways.

A third reason some adolescents are less effective multitaskers than adults is that, according to recent research, “heavy media multitaskers are less able to prioritize and sift information than light media multitaskers are.” A 2009 study of multitaskers’ abilities showed that “heavy media multitaskers are more susceptible to interference from irrelevant environmental stimuli and from irrelevant representations in memory. This led to the surprising result that heavy media multitaskers performed worse on a test of task-switching ability, likely due to reduced ability to filter out interference from the irrelevant task set.” Speed and switching has come at the cost of executive function (judgment), and heavy media multitaskers are becoming wired in this way.

What We Can Do

In sum, key parts of the brain are all dynamically connected in learning, memory, and executive function. Therefore:
  • working memory needs to be protected from overload in order to have time to find and make meaningful connections with existing long-term memories stored in the peel of the brain;
  • short-term memories need to be revisited over time in order to become long-term memories, or they will fragment, fade, or distort;
  • learners need to care about what they learn, but not too much, because chronically overstimulated amygdalas actually inhibit memory formation;
  • the focusing, priority-setting, and decision-making parts of the brain need to be cultivated as they develop (they will wire as they fire), which happens from childhood and continues throughout life.
  • The Internet and the way we use our information devices interfere with optimal brain function and development in ways that we can address.
  • Every teacher and every parent should understand the challenges of cognitive overload.
  • Unless multiple inputs are carefully choreographed to complement one another, they will interfere with memory and learning. In other words, a screen of text with clickable links is less helpful to learning than a screen or a page with no links or other distractions.
  • Banish the teacher complaint “I taught the material; the students didn’t learn it!” Given our knowledge of both how the brain functions and how cultural behavior interferes with the ability of the brain to learn, we need to do more than focus on content. We need to help students develop healthy patterns of learning.
  • Banish the demand for ever-more accelerated course “coverage.” What’s the point of “covering” information if it does not become part of a young person’s mind map? Anxiety over standardized tests and college placement drive the movement for more coverage, but brain research tells us that deep learning requires deep explorations and contemplation of subjects. Depth is better than width.
  • Activate the amygdala, but not too much! A chronically overstimulated child will be suffering from stress that will numb the brain, not optimize it.
  • Help young people develop their executive functions, knowing full well that the part of the brain that supports good decision-making is still under construction. Why else would young people think it a good idea to chase one another at high speeds on the highway, play blow-pong, or post party videos on YouTube?
In addition to helping young people become intelligent users of their devices and effective filters of infinite information, schools and families should cultivate the ability to switch gears from multi-focus to single focus, knowing that each has important benefits and different costs. Schools and families should set aside time for loosely structured creativity, which offers the opportunity for flow — the optimal state of learning — and encourages focus. They should emphasize the value of sticking with a hard problem and resisting distractions: this, neuroscientists know, is when humans can access their most creative minds. Schools and families can live in the 21st century and make enthusiastic yet discerning decisions about how we use our devices, access information, and manage our time and priorities so that we fire and wire our brains in ways that will be most productive and creative in the future.


1. Synthesizing multitasking, a process of higher-order brain functioning that is sometimes associated with a state called “flow,” is highly desirable but rarely experienced. In this type of multitasking, a person is managing and processing multiple related inputs to solve a complex problem. An example of synthesizing multitasking is a student working on a research project with multiple media inputs such as text, screen, documentary stills, recordings, an outline, and multiple drafts.
Karen Bradley

Karen Bradley, tech enthusiast, teaches ethics and comparative politics at Head-Royce School (California).