Multitasking has spent decades being treated as a virtue. We admire people who can "juggle a lot" and quietly wonder whether we should be handling more at once ourselves. Parents watch their teenagers do homework with a phone in one hand and music changing every three minutes, and accept it — perhaps because it mirrors what they do at their own desks during the workday. The ability to manage multiple things simultaneously feels like a sign of competence, adaptability, and efficiency.

There is one significant problem with this picture: true multitasking, for the vast majority of tasks most of us actually perform, does not exist. What we call multitasking is almost always something else entirely — something the research has a more precise and considerably less flattering name for. It is called task switching, and it is not a skill. It is a habit with a measurable cost attached to it every single time it occurs.

"Task switching is not an efficient way to do two things. It is an inefficient way to do neither thing particularly well."

What Is Actually Happening in Your Brain

The human brain does not actually perform two cognitively demanding tasks at the same time. What it does — what feels like multitasking — is shift attention rapidly between tasks, allocating focus to one thing, then another, then back again. Each shift carries a cost. Cognitive scientists refer to this as the switch cost: the time and mental energy expended in disengaging from one task and reorienting to another.

The switch cost operates on two levels simultaneously. The first is goal shifting — the process of telling your brain to stop doing one thing and start doing another. The second is rule activation — retrieving the specific mental rules, context, and working memory relevant to the new task while suppressing those of the previous one. Both processes take time. Neither is instantaneous. And both must repeat, in full, every time a switch occurs.

Research from the American Psychological Association has found that even brief mental blocks created by task switching can cost as much as 40 percent of productive time. To put that in concrete terms: a homework assignment that should take one hour can easily stretch to two and a half hours when a teenager is toggling between the assignment, text messages, a social media feed, a changing playlist, and a snack — not because the assignment got harder, but because the brain is spending an enormous proportion of that time in the overhead of switching rather than in the work itself.

And crucially, the person doing the switching rarely perceives this. Task switching feels productive because activity is continuous. The sense of busyness is real even when the output is not.

Try It Right Now: A Two-Minute Exercise

Before going any further, I want to invite you to experience the switch cost directly rather than simply read about it. This exercise takes about two minutes and requires only a pen, a blank sheet of paper, and something to time yourself — a phone's stopwatch, or the second hand of a clock.

The Task Switching Exercise
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Round One — Focused Tasks. Start your timer. Write the following phrase in full on your paper: "Task switching is a thief" Then, immediately below it, write the numbers 1 through 21 in sequence: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Stop the timer the moment you write 21. Record your time.
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Round Two — Switching Tasks. Start your timer again. This time, write one letter from the phrase, then one number, then the next letter, then the next number — alternating the entire way through, until all letters and numbers are written: T 1 a 2 s 3 k 4 s 5 w 6 i 7 t 8 c 9 h 10 i 11 n 12 g 13   14 i 15 s 16   17 a 18   19 t 20 h 21 Stop the timer the moment you write 21. Record your time.
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Compare. How much longer did Round Two take? For most people, the switching round takes anywhere from 50 to 100 percent longer than the focused round — sometimes more. The letters and numbers were identical in both rounds. The only difference was the switching. That gap between your two times is the switch cost, made visible.

Most people who try this exercise are genuinely surprised by the margin. They knew the second round would be slower — the alternating pattern is harder to hold in mind — but they did not expect it to be that much slower. That surprise is useful. It is the gap between how we experience task switching (manageable, normal, fine) and what task switching is actually doing to our output (costly, cumulative, and entirely real).

What This Looks Like for Children and Teenagers

For children and teenagers, the consequences of habitual task switching during homework and studying are significant — and frequently misread by everyone involved.

A child sits down to complete an assignment that should reasonably take forty-five minutes. Two hours later, the assignment is still unfinished, the child is frustrated and exhausted, the parent is frustrated and confused, and the evening has been consumed. The conventional interpretation — that the child is unmotivated, avoidant, or struggling academically — may be entirely wrong. The more accurate interpretation, in many cases, is that the child spent the majority of those two hours in the cognitive overhead of switching between the assignment and their phone, their music, their group chat, and whatever else was within reach.

The frustration compounds the problem. When task switching makes work feel harder and take longer than it should, the association between the work and the feeling of difficulty strengthens. Homework begins to feel aversive before it has even started, because the child's experience of homework has consistently been one of effortful struggle — not because the material is beyond them, but because the conditions in which they have been attempting it have been working against them the entire time.

For teenagers in particular, the pull of the phone during homework is not simply a failure of willpower. The social stakes of adolescence are genuinely high. A text message left unanswered for an hour feels, in the moment, like a social risk. Social media generates a low-grade but persistent pull toward checking — the same dopaminergic reward loop discussed in last month's article on screen time. Understanding this does not excuse the behavior, but it does clarify that addressing it requires more than telling a teenager to try harder.

What This Looks Like for Adults

Adults tend to be somewhat more sophisticated in how they rationalize task switching. We call it "keeping multiple plates spinning." We describe ourselves as "responsive" when we answer emails as they arrive rather than in dedicated blocks. We take a degree of quiet pride in having a lot going on simultaneously.

The research does not share that pride. Studies on workplace productivity consistently find that workers who attempt to handle multiple cognitively demanding tasks concurrently — responding to messages while drafting documents, monitoring news while preparing reports, fielding calls while reviewing data — produce lower quality output, make more errors, and take longer to complete individual tasks than workers who tackle one thing at a time in focused blocks.

There is also an important distinction between tasks that genuinely can run in parallel and tasks that cannot. Listening to music while folding laundry does not produce a meaningful switch cost because folding laundry does not require the kind of sustained, rule-governed cognitive engagement that listening to music also requires. Drafting an email while listening to a podcast, on the other hand, does — and anyone who has read a sentence of their own writing and realized they have no idea what they just said has experienced the collision between two competing linguistic tasks in real time.

Practical Strategies for Reducing Task Switching

The goal, again, is not perfection. Interruptions happen, and certain roles genuinely require responsiveness. What follows are strategies drawn from the research and from clinical and practical experience that meaningfully reduce the switch cost without requiring conditions that real life cannot sustain.

For Children and Teenagers

  • Phone in another room during homework. Not face-down on the desk. Not silenced in a pocket. In another room. Research consistently finds that the mere visible presence of a smartphone reduces available cognitive capacity, even when the phone is not being actively used. The physical distance matters. A charging spot in the kitchen or hallway — established as a routine rather than a punishment — removes the temptation without requiring ongoing willpower to resist it.
  • One subject at a time, fully completed. Encourage children to finish one assignment before opening the next rather than working partially on several simultaneously. Partial completion keeps the previous task's mental context active, which increases the cognitive load when switching to the next subject. Completion provides a genuine clean break.
  • Work in defined time blocks with built-in breaks. Structured approaches like the Pomodoro technique — twenty-five minutes of focused work followed by a five-minute break — give children a predictable rhythm that makes sustained focus more achievable. Knowing a break is coming in twenty minutes reduces the urgency of any distraction that arises in the meantime. During the break, the phone is available. During the block, it is not.
  • Establish a consistent homework environment. The brain forms associations between physical environments and the mental states associated with them. A dedicated, consistently used homework space — cleared of unrelated items, with the same lighting and setup each time — becomes associated over time with the mental mode of focused work. This is a small structural intervention with a meaningful cumulative effect.
  • Name what is happening, without shame. Children and teenagers who understand why task switching makes their homework take longer are more motivated to address it than children who have simply been told to put the phone down. Doing the exercise above together, and talking through what the results mean, makes the abstract concrete and invites the child into the conversation as a participant rather than a subject of correction.

For Adults

  • Batch similar tasks together. Email, phone calls, administrative work, and creative or analytical work draw on different cognitive modes. Grouping tasks that require the same mode — handling all email in two defined windows per day rather than responding as each message arrives, for instance — dramatically reduces the number of mode shifts and the overhead each one carries.
  • Protect at least one block of uninterrupted time daily. Even ninety minutes of genuinely uninterrupted focus — notifications off, phone out of reach, a closed door if possible — produces a disproportionate amount of meaningful output relative to the same ninety minutes fragmented by interruptions. Identifying when in your day that block is most feasible and protecting it deliberately is one of the highest-return investments in productivity available to most adults.
  • Close unused tabs and applications. The digital environment mirrors the physical one. A screen crowded with open tabs, active notifications, and visible unread counts creates the cognitive equivalent of a cluttered desk — a persistent, low-level pull toward switching that requires ongoing effort to resist. Closing what is not currently needed is a small act with a real effect.
  • Give yourself permission to finish before responding. Much of adult task switching is driven by a felt obligation to respond immediately — to messages, to requests, to whatever just arrived. Giving yourself explicit permission to complete the thing you are currently doing before turning to what just arrived reframes responsiveness as a choice rather than a reflex. Very few things genuinely cannot wait thirty minutes.
  • Notice the rationalizations. The most common one is some version of "I work better with background noise / when I have a lot going on / under pressure." Sometimes this is true in a narrow sense — low-demand background stimulation like ambient music can support certain types of routine work. But when the "background" includes email, news, social media, and text messages, it is no longer background. Paying honest attention to output quality under different conditions, rather than relying on how the process feels, tends to be informative.

A Final Thought

The exercise at the center of this article takes about two minutes. The insight it produces, if you actually do it rather than simply read about it, tends to stick — because it converts an abstract claim about cognitive efficiency into a personal, tangible data point. You felt the switch cost. You watched it happen on paper.

That is the point. Task switching is not a moral failing, and the people who do it most — children with underdeveloped attentional systems navigating an environment engineered to pull at their focus, adults managing genuinely demanding professional and personal lives — are not lacking in effort or intelligence. They are operating in conditions that make sustained focus increasingly difficult, often without a clear picture of what those conditions are actually costing them.

The cost is real. It shows up in homework that takes three times as long as it should. It shows up in workdays that end with a feeling of exhausted busyness and very little to show for it. It shows up in the quiet frustration of feeling like you worked hard and somehow still fell short. Naming it accurately — not as multitasking, but as task switching, with a switch cost attached — is the beginning of being able to do something about it.

Disclaimer: This article is for informational purposes only and does not constitute clinical advice or establish a therapeutic relationship. If you have concerns about your child's focus, attention, or academic functioning, please consult a licensed mental health professional for guidance specific to your situation.