The human brain switches its attention constantly because it can’t focus on two things at once.
asserted
it → switch → things
Multitasking works until a task needs concentration.
asserted
task → work → concentration
Two tasks can run simultaneously, unless they need the same part of the brain or body.
asserted
they → run → brain
Walking and chewing gum, for example, can be done at the same time because they use different body parts and don’t require a lot of concentration.
asserted
they → chew → concentration
But texting and driving both need the same pair of eyes.
asserted
texting → drive → eyes
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And the front of the brain, which handles focus, does one thing at a time, so tasks that need it take turns.
asserted
that → handle → turns
This is when multitasking takes a toll.
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multitasking → take → toll
It’s called switch cost, when the brain takes a moment or two to recover from switching between information competing for attention,
Reading while someone talks to you can feel like doing two things at once.
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talks → call → things
But John Paul Minda, a psychology professor at Western University, said much of what people call multitasking comes down to the brain switching between sources of information.
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brain → say → information
And there is always some cost to that, he said.
asserted
he → be → that
The human brain takes in lots of things at once, “because we don’t know what the important information is until we’ve processed it,” he said.
asserted
he → take → it
“The idea of jumping around is just something that your brain does whether you want it to or not.”
asserted
it → jump → that
People who multitask a lot and think they are good at it are actually worse at it when they need to focus on two things.
asserted
they → multitask → things
That’s because “you’re kind of used to shifting your attention really quickly,” Minda said.
asserted
Minda → ’ → attention
Each shift takes “a few seconds or half a second” to recover, he said.
asserted
he → take → seconds
Can you get better with practice?
asserted
you → get → practice
Maximilian Riesenhuber, a professor of neuroscience at Georgetown University Medical Center, said some multitasking comes naturally and others, like tying your shoes while you talk, can become automatic with practice.
asserted
you → say → practice
“You can walk and chew gum, right?
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You → walk → gum
I mean, some things we can do naturally in parallel.”
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we → mean → parallel
Riesenhuber, along with Patrick Cox, an assistant professor of psychology at Lehigh University, led a study published this year in the Journal of Cognitive Neuroscience that tested whether practice could make a new task automatic.
uncertain
task → lead → Neuroscience
The 11 people in the test practiced sorting pictures of cars into two groups on a phone app, more than 30,000 times over five to 10 weeks.
asserted
people → practice → weeks
Brain scans were taken before and after the test.
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scans → take → test
Before the study, Riesenhuber said the accepted view was that practice made people better at switching between tasks, while the prefrontal cortex, at the very front of the brain, kept doing the work.
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cortex → say → work
After the test, the scans showed the sorting-cars task had moved to the temporal cortex, a region he said “does a lot for vision.”
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he → show → vision
“You kind of build a little program,” Riesenhuber said, “and then you send it to the other part of your brain, and then that takes over for that task.”
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that → build → task
Cox called the finding “a proof of concept” in an email to National Post.
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Cox → call → Post
Once trained, he wrote, some participants sorted the cars just as well with a second task added as they did without the additional task.
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they → train → task
But practice won’t make texting and driving work together any easier, Riesenhuber said, because you can only look at one thing at a time.
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you → make → time
“I don’t want people to think, oh yeah, I do texting and driving a lot and that’s going to work,” he said.
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he → want → texting
“I mean it’s just not going to work because you look at different places.
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you → mean → places
How many other tasks can be combined with training “is an exciting open research question,” Cox wrote.
asserted
Cox → combine → training
A pharmacist who is constantly being interrupted with calls could fill the prescription incorrectly.
uncertain
who → interrupt → prescription
“It is common for people to multitask, but this is at-risk behaviour as it increases the risk of error,” Natalie Borden, CEO of the Institute for Safe Medication Practices Canada, said in an email to National Post.
asserted
Borden → multitask → Post
The organization analyzes reports of medication incidents, including near misses.
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organization → analyze → misses
Pharmacies in participating provinces reported more than 27,600 medication incidents last year, an increase of six per cent over the year before.
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Pharmacies → participate → year
Environmental, staffing and workflow problems were the top contributing factors in 2024 and 2025, with interruptions “a large proportion of that,” Borden wrote.
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Borden → contribute → that
She called the problem “a system issue, and not an individual practitioner issue,” since frequent interruptions and unpredictable workloads are “not within the control of individual staff members.”
asserted
interruptions → call → members
Checking a phone at dinner or during a movie is multitasking.
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Checking → check → movie
Minda said people handle quick shifts of attention well but struggle to stay focused on one thing, “because your brain is always looking for the next thing.”
asserted
brain → say → thing
One lab test of multitasking has people remember strings of letters while solving simple math problems.
asserted
people → have → problems
…and 13 more, not listed.
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