Tuesday, July 1, 2008

Multitasking: Productivity Killer

A couple of years ago, I read Joel Spolsky's article "Human Task Switches Considered Harmful," and it resonated mightily. The key take-away from that article is this: Never let people work on more than one thing at once. Amen. The nice thing about Joel's article is that it explains why in a very compelling way.

Last week, a good friend emailed me a link to an article by Christine Rosen called "The Myth of Multitasking," which goes even further. It quotes one group of researchers at the University of California at Irvine, who found that workers took an average of twenty-five minutes to recover from interruptions such as phone calls or answering e-mail and return to their original task.

So it's not just me.

The "benefits" of human multitasking is an illusion. Looking or feeling busy is no substitute for accomplishment.

Here's a passage from the Rosen article that might get your attention, if I haven't already:
...Research has also found that multitasking contributes to the release of stress hormones and adrenaline, which can cause long-term health problems if not controlled, and contributes to the loss of short-term memory.
Translation: Trying too hard to do the information overload thing makes you sick, and it makes you stupid.

For as long as I can remember, I've hated the times I've been "forced" to multitask, and I've loved those segments of my life when I've been free to lock down on a train of thought for hours at a time. I believe deep down that multitasking is bad—at least for me—and literature like the two articles I've discussed here supports that feeling in a compelling way.

Here's a checklist of decisions that I resolve to implement myself:
  • When you need to sit down and write, whether it's code or text, close your door, and turn off your phone and your email. (Or just work the 10pm-to-4am shift like I did with Optimizing Oracle Performance.)
  • When you're in a classroom, if you're really trying to learn something, turn off your email and your browser.
  • When you're managing someone, make sure he's working on one thing at a time. It's obviously important that this one thing should be the right thing to be working on. But it's actually worse to be working on two things than working on just one wrong thing. Read Spolsky. You'll see.


robert said...

Although I hate this kind of comment because it does not add anything valuable...

I could not agree more. Unfortunately management thinks we need to be working on tons of things in parallel...

Unknown said...

There is a perfect analogy in Oracle. We all know calling PL/SQL function from SQL is harmful to performance, due to the context switches between the engines.
Multi-tasking incurs similar context switch cost that harms human performance/productivity.

Jared said...

I will go along with Robert - I couldn't agree more.

I will disagree with Robert on the value of the post however. If enough comments like this appear it shows that many people have been thinking along the same lines.

Multitasking (for humans) has always been a myth, and I personally have always disliked being asked/forced to do more than one thing at a time, for the reasons stated in the many recent articles on it.

When the term multi-tasking started being used in relation to computers (time sharing), computers didn't actually multi-task.

They just performed tasks very quickly and the CPU was relinquished for another task.

That's probably not news for many readers of this blog. It's also no longer entirely accurate with modern microprocessors, but that doesn't relate to the human CPU.

jan van mourik said...

This comment caught my eye: “Workers distracted by e-mail and phone calls suffer a fall in IQ more than twice that found in marijuana smokers.” So does she mean "Workers distracted by e-mail and phone calls suffer a fall in IQ more than twice that found in workers who were smoking marijuana.”? Or was she comparing the average worker with the average pot smoker? How did they test this? Where did they test this? i guess at some university somewhere, shouldn't be a problem to find a population to test on there. And what about hasj smokers?

Kurt Graustein said...

Todd Duncan has a great book called Time Traps on this topic. He suggests setting specific blocks of time in each day for "communication" (e-mail, phone messages, chat). Outside those blocks of time, when you are getting your most productive work done, turn those communication channels off.

Improbable said...

For all of us who hate (human) multitasking, here there is a good interview on distraction


oraclenerd said...

there is no such thing as multi-tasking. well, i can walk and chew gum at the same time (barely), but i cannot design one project and code something else at the same time. it's either or.

i might have 5 things on my plate, but i work on them one at a time, even if it's just 10 minutes on each one (sans distractions of course).

i am not oracle, i cannot run in parallel, i must context switch. bad bad bad. ;)

Cary Millsap said...

Bad bad bad is absolutely right. Context switches on our machines are expensive, too, by the way. Just not 15 minutes a pop.

Brian Tkatch said...

I think success at multi-tasking depends on personality type. On the MBTI, Ps, who can contrate very well on one subject, prefer to deal with more than one thing at once. Js are quite the opposite. Informal studies show there to be approximately the same amount of Js and Ps (Ps are actually very slightly more common).

It in my contention that Oracle DBAs are usually Js, because the database is all about rules. Even the Ps act like Js to some extent here.

robert said...

Jared, if you read my statement you will notice that I did not say Cary's article was invaluable but my comment - stating nothing more than agreement.