Divided Attention: What It Is and What Multitasking Costs

Divided attention is your ability to attend to two or more things at the same time, such as driving while talking or typing while listening on a call. It works well when at least one task is automatic, like walking. When both tasks need real thought, most people slow down or make more mistakes, because what feels like doing two things at once is often rapid switching between them. In one driving study, only 2.5% of people showed no cost at all.

Key Takeaways

Dividing your attention means handling two tasks at once. Selective attention means focusing on one thing and filtering out the rest; sustained attention means keeping that focus over time.
In general, people can perform only one cognitively demanding task at a time. With two hard tasks, “multitasking” is often fast switching, and switching between tasks costs time.
In a driving simulator study of 200 people, only 2.5% showed no drop in performance when they added a demanding second task.
Whether heavy media multitasking makes people more distractible is unsettled: an influential 2009 study found it, but later replications and a meta-analysis found little or no effect.

What is divided attention?

It is the capacity to process more than one source of information or carry out more than one task at the same moment. You use it when you cook while listening to a podcast, take notes while someone speaks, or drive while following directions. How well it works depends on how demanding each task is and how practiced you are at it.

An open psychology textbook from the City University of New York puts the limit plainly: “in general we can only perform one cognitively demanding task at a time.” Practiced, automatic skills are the exception. Walking needs almost no attention, so walking and talking is easy. Two thinking tasks, such as writing an email during a meeting, are another matter. Training can stretch the limit: the same chapter describes a classic 1976 study by Spelke and colleagues in which two participants were trained to take dictation while reading for comprehension.

Examples of divided attention

Example	Does it work?	Why
Walking while talking	Usually yes	Walking is automatic
Listening to music while cleaning	Usually yes	Cleaning needs little thought
Taking notes in a lecture	With practice	Listening and writing compete, but notes follow the talk
Driving while on a phone call	Often worse than people think	Both need attention, and lapses are dangerous
Writing an email during a meeting	Usually poorly	Both need active thought at once
Reading while someone talks to you	Usually poorly, without training	Both need attention to words

Divided vs selective vs sustained attention

The three are different jobs for the same limited attention. Divided attention spreads it across tasks, selective attention points it at one thing while ignoring the rest, and sustained attention holds it there over time. Most focused work needs selective and sustained attention more than the divided kind.

	Divided attention	Selective attention	Sustained attention
What it does	Handles two tasks at once	Focuses on one thing, filters out the rest	Keeps focus over a long stretch
Everyday example	Driving and talking	Following one voice in a noisy café	Reading a long report
Where it breaks	Two demanding tasks	Strong distractions	Long, monotonous tasks

When sustained attention fails, you zone out; we cover that in zoning out: why it happens and how to stop it.

Can people really multitask?

For two demanding tasks, almost nobody can without a cost. In a high-fidelity driving simulator, Watson and Strayer (2010) had 200 people drive while also doing a demanding memory-and-math task by ear. The vast majority did worse when they combined the two than when they did either one alone. Only 2.5% showed “absolutely no performance decrements”. The authors called them supertaskers.

What feels like multitasking is often switching. In four experiments, Rubinstein, Meyer and Evans (2001) found that alternating between tasks cost time compared with repeating the same task, that the cost grew with more complex rules, and that it shrank when there were clear cues about which task came next. Every switch from email to the report and back pays that cost again.

Does multitasking make you worse at focusing?

The evidence is mixed. In 2009, Ophir, Nass and Wagner found that heavy media multitaskers, people who often use several media at once, were more easily distracted by irrelevant information and, surprisingly, worse at task switching. That study is widely quoted. Later work was less clear. In two replication studies and a meta-analysis of 39 effect sizes, Wiradhany and Nieuwenstein (2017) found a weak link that became non-significant after correcting for small-study effects.

A 2018 review by Uncapher and Wagner (Wagner co-wrote the 2009 study) concluded that the balance of evidence points to poorer performance in heavier media multitaskers in some areas, especially sustained attention, while many studies find no difference, and the direction of cause is unknown. The fair summary: the costs of switching between tasks are well established; lasting damage from a multitasking habit is not.

When does dividing attention work?

Dividing attention works when at least one task is automatic or very easy, when the tasks use different senses or kinds of thinking, and when nothing important rides on a small error. It fails when both tasks are demanding, when both use language, or when a lapse is dangerous. Practice moves tasks toward automatic, so a combination that is hard at first can get easier.

How to reduce the cost of divided attention

You cut the cost by dividing your attention less often and switching more deliberately. Do demanding work one task at a time in protected blocks, batch small tasks together, and make each switch clear and planned instead of letting notifications decide. These are the practical steps that follow from the switching research.

Single-task the hard work. Give one demanding task a block of time with nothing else open. Single-tasking is the habit, and deep work is the longer version.
Batch the small stuff. Answer messages, file and approve things together, in one or two slots a day, instead of interleaving them with focused work.
Make switches explicit. Rubinstein’s study found that clear cues shrank the switching cost. Before you change tasks, write the next step of the one you are leaving and name the one you are starting.
Turn off notifications during focus blocks. Each alert invites a switch you did not choose.
Use a time box. A set block for one task makes it easier to say no to the second one. Our guide to timeboxing covers how.
Keep easy pairings. Music while cleaning or a walk during a call is fine; save your full attention for tasks that need it.

If you find yourself switching constantly because nothing holds your attention, monk mode is a stricter way to clear distractions for a set period.

How FocusBox helps you single-task

FocusBox is a productivity app for planning and focused work, on the web and on iPhone and iPad. It is built around working through one task at a time.

You give each task a duration, start its timer and work through your list one task at a time, which turns single-tasking into the default. Full screen mode shows only the task in front of you, and alarms mark the end of a focus block with a visual or visual-and-sound signal, so the switch to the next task happens when you planned it.

Frequently Asked Questions

What is an example of divided attention?

Driving while talking on the phone, taking notes during a lecture, or cooking while listening to a podcast are all examples. In each, attention is split across two tasks at once. It works best when one of them, like walking or simple chores, is automatic, and worst when both need real thought.

Is multitasking the same as divided attention?

They overlap. The first is the capacity to attend to two things at once; multitasking is the everyday name for trying. For two demanding tasks, research suggests most multitasking is actually rapid switching between them, and each switch costs time, especially when the tasks follow complex rules.

What is the difference between divided and selective attention?

The divided kind spreads your focus across two or more tasks at once. Selective attention points it at one thing and filters out everything else, like following one voice in a noisy room. Most focused work relies on selective attention, which is why distractions and notifications cost so much.

Are some people good at multitasking?

Very few. In a driving simulator study of 200 people doing a demanding second task, only 2.5% showed no drop in performance, and researchers called them supertaskers. Most people show a cost, and the switching that feels like multitasking still costs time.

Why is doing two things at once so hard?

Attention is limited, and two demanding tasks compete for the same resources. When both need active thought, the brain tends to switch between them rather than run them together. Practice helps mostly by making one task more automatic.