It’s a common occurrence: You’re sitting at your desk, lost in thought, trying to solve a problem that’s been blocking your work all week.
Deep in your brain you’re building a structure of thoughts and possibilities undreamed of in anyone’s philosophy: You identify concepts and stack them against each other, turning them and flipping them and slotting them together. Like a keystone arch, as soon as it’s finished it’ll be strong enough to stand for generations—but it would topple to the ground in an instant if you stopped holding the pieces together before it was done.
A colleague comes along and notices you sitting there, maybe with your mouth hanging ever-so-slightly open, maybe with your head cocked sideways and one eye twitching and the general look of a person who has just inhaled a bug (just me?), and it’s obvious you’re not doing anything, so he taps you on the shoulder and says, "Can I just steal your brain for a moment? I wanted to ask you…"
And there, in that instant, the glorious half-arch you've been struggling to hold together comes crashing to the ground around you.
Like many of life’s most infuriating events, it’s easy to pin this one on people just generally being terrible. And hey, maybe people are just terrible. But there’s another theory which says it all comes down to miscommunication and different people accustomed to two very different kinds of work, so (in the name of charity and goodwill) let’s examine the generous possibility instead.
Brick by Brick
These two types of work were first identified, to my knowledge, by the programmer and essayist Paul Graham. The first type of work he describes can be interrupted harmlessly—nothing is lost if you stop for a second (or an hour, or a day) and come back to it later. An example might be building a simple pyramid out of wooden blocks (don’t pretend you don’t miss it). If someone wants to talk to you while you’re building your wooden pyramid you can easily stop, put down the block you were holding, and go off to chat for a minute or five; the tower will still be there when you come back, and you’ll have no problem picking up where you left off.
For a person accustomed to this kind of work, it’s obvious that if a colleague comes along and needs your brain for a moment, you should stop what you’re doing and help. Those 30-second interruptions cost them exactly 30 seconds, and what kind of person can’t spare 30 seconds for a friend in need?
The second type of work, however, is a completely different matter. The second type of work is like building our arch: If you stop for even an instant, you might drop half the pieces, drop the knowledge you were slowly accumulating of the strong points and weak points and which blocks go where. In these situations, a 30-second interruption can cost you a great deal more than 30 seconds—I’d argue, in fact, that for a Do Not Disturb task, a single brief interruption can easily halve your productivity.
Square by Square
Does that sound extreme, maybe even implausible? Here’s a (slightly) mathematical spin that I think shows why it’s credible. (Bear with me on the math, I promise it will be worth it.)
One way to think about harmlessly-interruptible work is that it’s any kind of task where productivity is linear in the amount of time you spend on it. That simply means that if you spend 2 units of time on a task, you get 2 units of output back. For linear-type work, it really doesn’t matter whether those 2 units of time are spent in an uninterrupted two-hour block or in two separate one-hour blocks, because 1 + 1 = 2. (You can check my sums, I’ll wait around.)
Once we see it this way, it’s easier to figure out what’s going on with the Do Not Disturb work. Do Not Disturb work is any kind of task where productivity rises in a variety of non-linear ways: For example (though there are many others), if productivity rises in line with the square of time spent. This could mean that a 2-hour block of work gives us 2-squared units of productivity, which is 4 units of productivity, but two one-hour blocks of work give us only 1² + 1² units of productivity, which is 2 units of productivity. Suddenly that 30-second interruption makes a huge difference:
As Graham puts it, for Do Not Disturbers, "The cost of having someone from personnel call you about a form you forgot to fill out can be huge. This is why hackers give you such a baleful stare as they turn from their screen to answer your question. Inside their heads a giant house of cards is tottering."
Door to Door
As I said previously, I think that the simple misunderstanding between people who are accustomed to harmlessly-interruptible work and people who are accustomed to Do Not Disturb work causes many of the infuriations of the modern workplace. The harmlessly-interruptibles get exasperated at that one colleague who is so obstinate and anti-social she refuses to stop for the briefest conversation, or even take out her earbuds for half a minute, when someone is at her desk with an important message to give her.
Meanwhile, the Do Not Disturbers can’t fathom how their colleagues could be so un-empathetic as to wreck two hours of work in a heartbeat… just to tell them that a meeting they never wanted to attend has been moved from three to three-thirty. If we could all just hang a sign on our door saying what kind of work we’re in the middle of, so that colleagues could know in advance whether to cut in for a second or save it for later, everyone would be better off.
Of course, this assumes that you have a door to hang that sign on. Here we see another insight from the Two Types of Work theory. I believe that the eternal tension between open-plan and private offices can be explained (among other factors) by the two types of work. If you’re doing harmlessly-interrupted work, then it might make sense to be surrounded by your colleagues, bouncing ideas, shooting quick questions—the productivity gained by immediate answers could outweigh the small losses resulting from those brief interruptions.
Graham writes that he "once saw a recruiting ad for Microsoft with a big picture of a door. Work for us, the premise was, and we'll give you a place to work where you can actually get work done."
In terms of Do Not Disturb work, on the other hand, an open plan office is a living nightmare—so much so that companies in the know make private offices for Do Not Disturbers a major part of their recruitment package. Graham writes that he "once saw a recruiting ad for Microsoft with a big picture of a door. Work for us, the premise was, and we'll give you a place to work where you can actually get work done." Similarly, when programming guru Joel Spolsky was having new offices designed for his company, Fog Creek, he told the architect that "private offices with doors that close were absolutely required and not open to negotiation."
In fact, Spolsky went so far as to completely eschew outside funding for his company partly because "I don't think it's possible to have private offices for developers when you're VC-funded...I think that it's worth paying for in terms of the productivity you get…[but] it would be considered completely unacceptable by the average VC…because it's considered an extravagance of a successful company or something like that. And, you know, 'Why aren't you all in the same room talking?'" Why aren’t you all in the same room talking?—I think we all know the answer to that one.
You've Got Mail
I similarly believe that Do Not Disturb work is at the heart of the reason why so ⋅ many ⋅ productivity ⋅ writers argue for blocking out the first few hours of the day for completely ignoring email. Email is the ultimate 30-second distraction: It hardly takes a moment to read and reply to somebody’s message, and while you’re doing it you feel productive and useful and meaningful in the world. But every time you break from your Do Not Disturb work to answer that quick question (or just impulsively flip to your email tab), you’re dropping half the bricks in your arch, or maybe stopping yourself from starting an arch in the first place. Nothing breaks the imagination like a letter from a friend.
Of course, the notion that there are two totally different types of people, doing totally different types of work, is more than a little oversimplified (a stark dichotomy that turns out to be oversimplified? Who would have thought!). While some of us will immediately recognize Do Not Disturb work as the main type of task we do each day, I think most of us have some amount of Do Not Disturb work in our lives which we ought to prioritize in the early morning, or late at night, or whenever it is that we have even the slightest possibility of finding (and guarding) uninterrupted work time.
Which is to acknowledge an inconvenient truth: An uninterrupted block of time, unless guarded jealously, will never stay that way—a slow devolution towards disorder seems to be the natural way of things unless we intervene decisively against it. We need to fence off any possible Do Not Disturb time using whatever measures necessary: switching off WiFi, working inside the closet, pretending we have to stay home today because the kids have chicken pox (again). If you’re going to build an arch, it’s often necessary to spend resources first on a fence around that arch — a fence to keep the baying hounds of the outside world at bay.
A Space in Time
A few more tips about Do Not Disturb work. First, if you can possibly leave your Do Not Disturb time open-ended—say, I’ll start this work at 8 a.m. and whenever I happen to finish it I’ll go back to checking emails—that’s very much for the best.
Graham writes that, in some ways, "scheduled distractions may be worse than unscheduled ones. If you know you have a meeting in an hour, you don't even start working on something hard." It isn’t possible to engage with Do Not Disturb work indefinitely; at some point your brain fuzzes up like an old peach, and you really must go do something else. But there’s a very big difference between driving on an open road until you run out of gas and driving with a cop car bearing down on your rearview mirror: In the latter case you’re likely to say, "Well, I wouldn’t have got much more done anyway," and pull over to the shoulder much sooner than necessary.
Graham writes that, in some ways, "scheduled distractions may be worse than unscheduled ones. If you know you have a meeting in an hour, you don't even start working on something hard."
Second, it’s important to understand that not all distractions are created equal. As Graham notes, "The danger of a distraction depends not on how long it is, but on how much it scrambles your brain. A programmer can leave the office and go get a sandwich without losing the code in his head. But the wrong kind of interruption can wipe your brain in 30 seconds."
Graham clearly means a sandwich from that one local sandwich place that the person always goes to, because the exact same sandwich run would be absolutely arch-toppling if it involved going to a different café and having to think about anything. The secret to acceptable interruptions, while hard to describe precisely, could be something about your ability to deal with them on autopilot: They must be completely unsurprising and not require any decisions.
Work With Me
Finally, a word to the managers of the Do Not Disturbers. I realize that, as an executive, this can all start to sound like special pleading. Not only am I saying that I want to be left alone and not be disturbed under any circumstances—when it looks to a normal observer like I’m sitting here and daydreaming—but I’m also saying that my colleagues aren’t allowed to disturb me for even 30 seconds with important questions, yet I can wander off for 30 minutes at lunch and that’s a-okay. How does that even make sense? It doesn’t, I know. It sounds insane. So I realize there’s a lot to take on trust here.
I think it’s important to appreciate, though, just how enjoyable Do Not Disturb work is. You remember, as a kid, how you invented fantasy worlds in your head, filled with brilliant inventions and fantastical quests, and when your folks called you down for dinner you simply ignored them because you didn’t want to lose your place in the story? That’s Do Not Disturb work. How about the feeling when you meet a special someone, and the only thing you want in the world is to stay up all night walking and talking with them, trying to understand them at the deepest level? That’s Do Not Disturb work. Do Not Disturb work is Newton gazing at the apple tree; Do Not Disturb work is Paradise found. Do Not Disturb work is, far and away, the greatest part of a working day, so I firmly believe that any person tasked with doing it and given the conditions to make it possible would be absolutely crazy to spend those sacred hours doing anything else.
Managers, I swear, this is a chance to be a hero: Stand boldly between your Do Not Disturbers and the outside world with a sword in your hand shouting "none shall pass." Because deep in their brains, in measureless caverns, your Do Not Disturbers are building arches and citadels and domes in the air—the structures that the greatest companies are made from.
This essay is lovingly dedicated to the hours 8 till 12, without which none of my real work would ever get done.