The True Cost of Multi-tasking

Picture of a sunset over water
My view last week “off the grid”

I spent last week “off the grid” on an island in Lake Michigan.  No internet, no email, no cell phones. It was different, interesting, and strange. I was actually glad to get back to the grid. But the experience made me think. The major difference for me was that I stopped “multi-tasking”.

Task switching, not multi-tasking —  A while ago I wrote a post about multi-tasking, and the research at Stanford that shows that even younger people aren’t good at multi-tasking.  But the term multi-tasking is actually a misnomer. People can’t actually do more than one task at a time. Instead we switch tasks. So the term that is used in the research is “task switching”.

Task switching is “expensive” — There has been a lot of research on task switching. Here’s what we know from the research:

  • It takes more time to get tasks completed if you switch between them than if you do them one at a time.
  • You make more errors when you switch than if you do one task at a time.
  • If the tasks are complex then these time and error penalties increase.
  • Each task switch might waste only 1/10th of a second, but if you do a lot of switching in a day it can add up to a loss of 40% of your productivity.
  • Task switching involves several parts of your brain: Brain scans during task switching show activity in four major areas: the pre-frontal cortex is involved in shifting and focusing your attention, and selecting which task to do when. The posterior parietal lobe activates rules for each task you switch to, the anterior cingulate gyrus monitors errors, and the pre-motor cortex is preparing for you to move in some way.
Does having more communication channels encourage task switching? When I was off the grid I found that I started doing one task at a time. I would do one thing for several minutes, and in many cases several hours. I believe that being online encourages task switching. When you can go from email to chat to texting to twitter to phone to facebook you switch tasks more. When I was off the grid all my channels were gone. So instead I spent time with one task and with one program. One day I worked in IPhoto for 3 hours straight.
Additional costs– One last insight from my week off the grid: I was much less agitated. It’s my hypothesis that task switching not only wastes time and increases errors. Task switching causes fatigue, exhaustion and agitation.
Less task switching = more happiness? — Now that I am back on the grid I wonder if I can break the task switching addiction and improve my mood, energy, happiness, productivity, and error rate? Can I beat the task switching habit?
What do you think? Have you been able to do less task switching? Have you tried?
And for those of you who like to check out the research:

Meyer, D. E., Evans, J. E., Lauber, E. J., Gmeindl, L., Rubinstein, J., Junck, L., & Koeppe, R. A. (1998). The role of dorsolateral prefrontal cortex for executive cognitive processes in task switching. Journal of Cognitive Neuroscience, 1998, Vol. 10.

10 Best Posts of 2009

It’s that time of year — so here is my list of the 10 best posts from my blog in 2009. I chose the 10 that I believe have had the greatest impact/most thought provoking/most interest from my readers.

#1: Dopamine Makes You Addicted to Seeking Information — I thought this was an interesting post when I wrote it, but it surprised me how quickly it took off virally; more than any other post I’ve written!

#2: Eyetracking — 7 Traps to Avoid — Another surprise to me how popular this post was.

#3: 7 Steps to Successful Web Site Redesign — I think Jacek Utko has an important view of the world.

#4: Your Attention is Riveted By Pictures of People — If people knew how important this is I think they’d change the pictures they put at their web site.

#5: Web Site User Experience Anatomy — Not one of my posts, but a guest post by Craig Tomlin, and an interesting way to think about web sites. Continue reading “10 Best Posts of 2009”

7 Strategies to Replace Multi-Tasking

In a previous blog I talked about the research that shows that multi-tasking is not effective. (See 100 Things You Should Know About People: #7 — People Can’t Multi-Task) So if multi-tasking is not effective what should you do? How do you effectively cope with all the input and distractions you have in your life, especially at work?

1: Remember the 80/20 rule — I’m sure you’ve heard about the 80/20 rule. The context here is that 20% of the work you do gives 80% of the impact and effectiveness. We often make the mistake of thinking that being busy means being effective. And the busier we get the more multi-tasking we end up doing. According to the research that means we are getting less effective the “busier” we get. Focus on identifying the 20% of your tasks that are really effective.

2: Implement “batch processing” — Do you sit at your desk with your email open and then get sucked into reading and answering emails all day long every time they come in? This encourages multi-tasking. Instead, try batch processing your emails. Decide on certain times of the day (in the morning, at noon, in the late afternoon, for example) that you are going to check and deal with email. Some people (Timothy Ferriss, for example, author of The 4-Hour Workweek) say that you can get really radical with this idea. Ferriss advocates that you check email once a day or less! If you are like me, that radical an idea is probably not feasible, but experiment with this idea of batch processing. You can use this not only for email, but for anything that is usually a distraction for you, such as making phone calls, checking voicemail, etc. If you do batch processing you can then eliminate that task as a multi-tasking distractor during the other parts of your day. Continue reading “7 Strategies to Replace Multi-Tasking”

100 Things You Should Know About People: #7 — You Actually Can't Multi-Task

I know it’s popular to think that you are multi-tasking, but the research is clear that people actually can’t multi-task, with one specific exception.

One thing at a time — For many years the psychology research has shown that people can only attend to one task at a time. Let me be even more specific. The research shows that people can attend to only one cognitive task at a time. You can only be thinking about one thing at a time. You can only be conducting one mental activity at a time. So you can be talking or you can be reading. You can be reading or you can be typing. You can be listening or you can be reading. One thing at a time.

We fool ourselves — We are pretty good at switching back and forth quickly, so we THINK we are actually multi-tasking, but in reality we are not.

The one exception — The only exception that the research has uncovered is that if you are doing a physical task that you have done very very often and you are very good at, then you can do that physical task while you are doing a mental task. So if you are an adult and you have learned to walk then you can walk and talk at the same time.

Then again, maybe there isn’t an exception —  Even this doesn’t work very well, though. A study being published in December shows that people talking on their cell phones while walking, run into people more often and don’t notice what is around them. The researchers had someone in a clown suit ride a unicycle. The people talking on a cell phone were much less likely to notice or remember the clown.

But the millennial generation can multi-task, right? — A study at Stanford University demonstrates well that multi-tasking doesn’t work, even with college students. Clifford Nass’s study (published in August of 2009 in the Proceedings of the National Academy of Sciences), found that when people are asked to deal with multiple streams of information they can’t pay attention to them, can’t remember as well, and don’t switch as well as they would have thought.

So what should you do? — One thing at a time!

For more information:

on the Stanford study:Stanford Study on Multi-Tasking

On the clown and unicycle research: Ira E. Hyman Jr *, S. Matthew Boss, Breanne M. Wise, Kira E. McKenzie, Jenna M. . “Did you see the unicycling clown? Inattentional blindness while walking and talking on a cell phone”. Applied Cognitive Psychology, December, 2009.


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100 Things You Should Know about People: #1– You Have "Inattention Blindness"

I’ve decided to start a series called 100 Things You Should Know about People. As in: 100 things you should know if you are going to design an effective and persuasive website, web application or software application. Or maybe just 100 things that everyone should know about humans!

The order that I’ll present these 100 things is going to be pretty random. So the fact that this first one is first doesn’t mean that’s it’s the most important.. just that it came to mind first.

I hope you enjoy this series. Make sure to let me know by posting comments.

So here’s #1 — Inattention Blindness

First let’s start with a little test for you to take. Watch the video below:

This is an example of what is called “inattention blindness” or “change blindness”. The idea is that people often miss large changes in their visual field. This has been shown in many experiments. Here is a description of an experiment conducted outside the lab:

So what does this mean if you are designing a website or something on a computer screen? It means that you can’t assume that just because something is on the screen means that people see it. This is especially true when you refresh a screen and make one change on it. People may not realize they are even looking at a different screen. Remember, just because something happens in the visual field doesn’t mean that people are consciously aware of it.


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