How many different things are you trying to do right now? Reading this blog post while listening to a podcast, posting on Instagram and checking email? It’s easy to think you’ll be more productive by doing lots of things at once. But it turns out for almost all of us, effective multitasking is an illusion.

A different take on driving and texting. Photo by Michiel Gransjean via Flickr.

You’re not really multitasking

With the possible exception of texting while driving, you probably think multitasking is something to aspire to. But the reality is, trying to do multiple things at once actually slows you down and leads to more mistakes. We are simply no good at trying to engage with more than one decision-making process at a time.

In fact, experts tell us even the term multitasking is wrong: we should call it task switching. Researchers suggest we may lose up to 40% of our productivity by trying to multitask. What feels like multitasking is actually rapid switching between tasks and the time it takes to switch between tasks all adds up.

Think it only takes a few seconds to jump between email and the report you urgently need to write? No big deal unless you are switching every time you get a new email notification. And how long does it take you to get to the point where you are writing effectively again? Research shows it takes an average of 23 minutes. In some cases, study volunteers never got back into the flow of writing.

In another study, volunteers were asked to memorise either a 7-digit or single-digit number while eating. Those who had the more challenging memory task were less aware of the flavour of the food they were eating. At the same time, they ate more of both the sweet and salty food on offer.

Some tasks are easier than others

If multitasking is so hard, perhaps you’re wondering why you can read this blog, eat your lunch and listen to music all at once.

How easy it is to juggle tasks depends on how engaged your prefrontal cortex is during the activity. Natural behaviours like walking, talking and eating don’t take a lot of brain effort so we can do those things at the same time as paying attention to something else.

Having said that, talking on your mobile while driving increases your risk of having an accident four-fold. It’s been shown to be equivalent to driving with a blood alcohol reading of about 0.08.

When 56,000 people were observed approaching an intersection in their cars, those who were talking on their mobiles were ten times less likely to actually stop at the stop sign.

Even walking at the same time as talking on your mobile takes up most of your brain’s attention. Only one quarter of people doing both noticed a clown on a unicycle ride past them who had been planted there by researchers.

And as soon as there are multiple tasks which require thinking, it becomes clear our brains simply aren’t wired for multitasking.

There are supertaskers among us

But all is not lost. Research has uncovered a small proportion of the population — about two percent — who have extraordinary multitasking abilities. Imagine simultaneously doing a driving test, solving complex maths problems and doing memory tests on your phone.

People who can easily do that have been called supertaskers and they have brains that actually become less active the more tasks they are trying to do at once. And that’s not all. Supertaskers do better, not worse, at each individual task the more simultaneous tasks they are doing.

The irony is that as soon as we hear that supertaskers exist, 90% of us decide we belong in that 2%! But research has shown that the people who multitask the most and are the most confident in their multitasking abilities tend to actually be the worst at it.

The cost of multitasking

Assuming like me, you are not a supertasker, it’s worth considering what our attempts at multitasking cost us.

Research suggests the more we attempt to multitask, the more we are training ourselves not to focus. We are effectively teaching ourselves that something unknown – an unread email or the next notification – is always more worthy of our attention than whatever task we are meant to be working on.

We sacrifice focus in order to ensure we don’t miss any unexpected surprises, but in the process we lose our ability to block out distractions. And that means we’re not very good at getting stuff done.

As Cal Newport says in his excellent book Deep Work,

Efforts to deepen your focus will struggle if you don’t simultaneously wean your mind from a dependence on distraction.

Links and stuff

• Think you might be a supertasker? Take this test to find out
• Read this story without distraction (can you?)
• Multitasking between devices is associated with poorer attention and memory