The Myth Of Multi-tasking

If you've been out job-hunting, you would probably have seen job ads that want people who can do several things at once.

"Ability to Multi-task" is probably one of the most common requirements a job applicant will see on job applications these days. It's unfortunate because I don't think "multi-tasking" means quite the same thing most employers think it means. To them, it's a cheap pretty way of saying "I should be able to load you with several different things at one go, and you should still be able to perform."

Work, slave!

Techies, however, know that even with ultra-fast computers, there is no such thing. Computers only seem capable of doing several things at one go because they are task-switching - carrying out bits and pieces of one process and then switching to the next process - very rapidly.

The next closest thing would be multi-processing. That's when one computer has two CPUs and they're using these processing units to simultaneously do stuff. This effectively means the multi-processing computer has two brains. There's no human being on God's green earth that has two brains, and no, I'm not counting cojoined twins!

The Good News

Human beings can multi-task. If, and only if, those tasks do not engage higher cognitive functions. In other words, if something comes as naturally as breathing (such as walking, swallowing and yes, breathing), all it really requires is your subconscious.

For example, let's say you're lost along a street. You're checking the road signs and Google Maps on your phone at the same time. Or are you? How many things are you actually doing at the same time?

You're breathing, because like most living organisms, you need a constant supply of oxygen.

You're walking, and instinctively avoiding collision with nearby objects.

You're checking out road signs and storing the information in short-term memory.

You're looking at the display on Google Maps to see if the information correlates with the information in your short-term memory.

Four things at one go! Or is it? Walking and breathing are managed by your subconscious.

And you're task-switching between reading road signs and checking Google Maps. You're not doing those two things simultaneously! The moment you start looking at your phone, you're no longer reading road signs. And vice versa. But no matter which you're doing, you're still walking and breathing.

The Bad News

It's the sucky human limitation that prohibits us from giving several different things our undivided attention all at once. (Yes, never mind unrealistic expectations from employers. It's our fault entirely. Curse our limitations!)

If you are talking to a customer, you can't be writing code at the same time. You're either doing one or the other, or doing a piss-poor job of both. Similarly, you can't be debugging a program while backing up a database, even if both happen to be your job. You have only one brain, and at any one point in time, you are doing only one thing.

OK, so let's call it "task-switching", then!

Call it whatever you want, the fact remains that this affects performance negatively. Hey, don't take my word for it. Try this experiment.

See the table below? Each column has a different formula. Start with the number 5. For every row (other than the first, which uses the number 5), use the result of the previous row in that column in place of y.

The first three rows has been done for you. Now do this for, say, ten rows.

	A	B	C
	(y + 5)	(y x 2)	(y + 10)
1.	10	10	15
2.	15	20	25
3.	20	40	35
4.	?	?	?
5.	?	?	?
6.	?	?	?
7.	?	?	?
8.	?	?	?
9.	?	?	?
10.	?	?	?

But wait... first, try filling all ten rows of Column A, then all ten rows of Column B, then all ten rows of Column C. Easy, right?

Now try filling the first row of Column A, the first row of Column B, and the first row of Column C, and so on until you complete ten rows. Not so easy this time, was it?

The point here is to illustrate that when your brain switches tracks, there's a cost in performance. You have to load a new formula in your head every time you go from Column A to Column B, then Column C. That's (3 x 10 = 30) thirty switches.

Whereas if you just did all ten rows in Column A first, you only had to apply one formula for ten rows, then another formula for the next ten rows in Column B, and another for the next ten rows in Column C. That's only three formulas.

Which method ultimately strikes you as more efficient? To a computer, there seems to be no difference because they perform that fast anyway. But it's your brain we're talking about. The human brain.

Even in software development, when devs are being assigned a list of bugs to fix, they're told to work on only one thing at a time. Anything else is just asking for trouble.

Finally...

I have no problem with employers wanting their employees to handle a lot of stuff at one go. After all, if your employers don't try to exploit you at all, what kind of employers would they be? The only problem is when they think that this shouldn't and doesn't affect performance.

Because it really fucking does.

And also with employers who insist that their employee should be able to "multi-task" and still perform superbly, yet raise all hell when they catch you making a private call on your phone while typing a document. Make up your bloody minds, please! You can't have your cake and eat it too.

Oh wait, you're the almighty boss. I guess you can, eh?

Simultaneous salutations,
T___T