YOUR BRAIN IS NOT A BROWSER WITH 47 TABS

We treat multitasking as a skill. Job descriptions ask for it. We wear it like a badge. And somewhere along the way, someone told you the price: multitasking lowers your IQ. It makes you dumber. You've seen the stat. You may have quoted it.

It's junk.

The stat you've been quoting is junk science

The "multitasking drops your IQ" figure traces to a single 2005 experiment run for Hewlett-Packard by psychologist Glenn Wilson — eight participants, never peer-reviewed, released as a PR press note and nothing more. The media inflated it into neuroscience. Wilson himself later disowned it, saying it proved next to nothing. And what it measured wasn't a loss of IQ — it was temporary distraction while phones buzzed and email pinged. Switch the noise off and the "lost points" come back.

So no, multitasking isn't quietly lowering your IQ.

The real finding is worse.

What the actual research shows

In 2009, Ophir, Nass and Wagner ran the study that matters (Cognitive Control in Media Multitaskers, PNAS 2009). They compared chronically heavy media multitaskers against light ones. The heavy multitaskers were worse at the thing that actually defines focus: filtering. More susceptible to irrelevant stimuli. Larger switch costs moving between tasks. Worse at ignoring information that didn't matter.

One caveat, stated honestly: the study is correlational. It shows heavy multitaskers are worse at filtering — it does not prove the multitasking caused it. The arrow could run either way. But the association is real, measured, and replicated — which is exactly what the IQ myth never was.

Your brain is not a browser

Here is why this is worse than an IQ hit. IQ is a score. Filtering is a faculty.

A browser with 47 tabs open isn't running 47 streams of attention — it's one processor thrashing, swapping context in and out until everything slows down. Your brain does the same. It does not parallel-process knowledge work; it serial-switches, and every switch carries a cognitive cost that accumulates the way unquestioned process does — invisibly, until throughput falls off a cliff.

The cost isn't IQ points you get back after a nap. It's the slow erosion of the one skill deep work is built on: the ability to decide what to ignore.

Close the tabs

Your brain is not storage, and it is not a browser. Stop holding 40 open loops in your head and 40 tabs on your screen.

→ One window. One objective. Zero notifications. → If you wouldn't let a stranger walk into your office and scream in your face, don't let a push notification do it. → Treat attention as finite, because it is.

Close the tabs. Then close the rest.