A former McKinsey partner thinks she's identified the biggest mistake we make at work

Juggling demands in the modern workplace can be hard, whether you are dealing with a continuous flow of emails or colleagues seeking help.

But an economist and former McKinsey partner might have discovered the biggest obstacle to productivity at work.

Caroline Webb said the culprit is multitasking.

Webb shared her discovery at a conference by the Royal Society for the Encouragement of Art, Manufactures and Commerce (RSA) in a presentation called “How to have a good day”.

“Our conscious brain can only do one thing at a time,” she said.

Webb asked the audience to recite a series of numbers (1, 2, 3, 4) as fast as they could to prove her point. Then, she told them to do the same with letters. The audience performed both tasks without difficulty. But when the speaker asked them to switch from letters to numbers (A, 1, B ,2 ) most gave up on the task in the middle of it.

“Multitasking makes you do between two to four times as many mistakes and slows you down even beyond that.”

When we think we are multitasking our brain is only processing a fraction of what is happening. It is actually switching its attention from email, to website, to colleagues to thoughts on lunch, according to Webb.

“You are losing some time and mental energy in that switch, so you are slower and more error prone when you multitask,” she said.

Single tasking is the way our brain really wants to work, according to Webb, whose own firm Sevenshift shows clients how to use behavioural science to boost their professional effectiveness.

Webb suggested workers should do these four things:

First chose the most important task of the day. Then put your phone on aeroplane mode while you do it. These two simple things will help you stay focused on your most important assignment of the day, according to Webb.

A pair of headphones is also a great tool for cutting out disruptive noise but it also signals to your colleagues that you are focusing and do not want to be disturbed, Webb suggested.

Going away from your desk to think without the distraction of the computer can also help you to prioritize and save time.

Webb said that the tool that has helped the most was a timer that she put on her desk to count down the minutes she was able to stay offline.

Starting at 5 minutes she managed to build it up to 90 minutes without checking her emails. She finally put it back to 45 minutes as she understood her team could not cope with her being offline for more than an hour.

“Single tasking magically gives you back time in the day. Look for a chance to do it whether you can. Be kind to yourself, start small,” Webb said.