If you spend a third of your life on your mattress, you'd want to buy the best possible one and make sure that sleeping on it makes you feel fresh and rested, right?

Similarly, if you’re spending a third of every weekday (or more) in front of the computer, you’ve probably given some thought to how your monitor setup affects your productivity and well being.

For years, the general consensus has been that an extra monitor (or two, for that matter), is a very effective way to increase productivity. This setup was strongly recommended by a couple of New York Times articles, citing industry research. It didn’t seem to matter though that this research was sponsored by monitor vendors such as NEC, Microsoft and Dell.

But even if monitor sales are not the main reason behind the research, there are plenty of reasons why a single, large monitor might actually be a better choice for your productivity.

Singletasking

Multitasking has been proven to have high cognitive costs and to take its toll on productivity.

In fact, it can take up to 40% more time to multitask than to singletask. There is also a lag time associated with shifting focus from one task to another, during which your brain adjusts. And it takes even longer for the brain to adjust in complex tasks.

What’s more, multitaskers are more prone to errors and are more likely to be forgetful.

By physically removing a secondary monitor from your desk, you're placing all your focus and concentration on a single display. That’s not what the vendor-sponsored research would have you think, though. Here’s the scenario a whitepaper from Dell cites, in favour of a dual monitor setup:

“Think about a typical usage scenario: A worker may be viewing an Excel spreadsheet, while their e-mail client, Web browser, IM application, and Windows Explorer windows are running in the background. To get from one to another requires switching active windows and taking the focus away from critical work.”

Actually, this worker’s focus is taken away from critical work since her focus is scattered among multiple things - not by the multiple windows themselves. In fact, it’s not even clear what the "critical work" is. Is she collaborating with team members, researching something on the web, replying to clients’ emails, or compiling an Excel spreadsheet? If she’s doing everything at once, the quality of her work is probably suffering.

In addition, diverting your attention from one monitor to another can cause you to lose track of what you’re actually working on. That’s why David E. Meyer, psychology professor at the University of Michigan, warns that scanning multiple screens rather than focusing on one task can negatively impact productivity, as people keep interrupting their thoughts.

The more pixels the merrier

Clay Johnson, author of The Information Diet, makes the argument that you should manage pixels, not monitors. That’s because even the vendor sponsored research suggests that the productivity gains are not due to the additional screen, but due to more pixels. In fact, even an NEC study concludes that “large widescreen monitors can be equally or more productive than dual screen monitors.”

But beware - the interaction between productivity and monitor display follows a bell curve pattern. While productivity does increase as screen size increases, there is actually a point where the screen space becomes too large, and productivity tapers off.

So how big is too big? A 22-inch widescreen monitor has a productivity gain of about 30% over a 19-inch standard monitor. Productivity seems to peak with a 26-inch widescreen monitor, which further improves productivity by 20% over the 22-inch monitor.

A 30-inch display already begins to negatively impact productivity, performing worse than a 26-inch, but it’s still better than a 19-inch display.

The same NEC study concluded that a single widescreen was consistently the best performing setup on text editing tasks and that workers who were rookies in their field showed a significantly higher performance on a single widescreen.

But whether you’re working on a single monitor or a dual monitor setup, you still have to find a productive way to manage your screen space. An application like Divvy can help you manage your workspace with less effort, and take the frustration out of trying to arrange your windows.

Improved ergonomics

We’ve seen that dual monitors can negatively impact productivity, but can they actually affect your health too?

Unfortunately, the answer is yes.

It’s obvious that a dual monitor setup requires more head and neck movements. But people also sit further away from multiple monitors so that they can take it all in by shifting their eyes rather than moving their heads - which results in a lot of squinting and neck-craning.

Also, most people give both monitors the same importance, and place them symmetrically in front of them, instead of giving one monitor importance over another. This impacts posture as it forces the neck to stretch forward and the spine to tilt forward.

Research has found that the head and neck movements associated with a dual monitor display can increase the risk of neck musculoskeletal disorders - and things get even worse with prolonged computer use!

With a single, large monitor you can reduce head these neck movements that are part of a dual monitor setup. And if you’re clocking serious hours at your workspace, you may appreciate this even more at the end of each day.

Our conclusion: a large monitor with a high pixel resolution will help you better focus and keep you healthier than a dual monitor display.

How many monitors are you using in your workspace? How do you work with your screens? What kind of impact does your work setup have on your productivity? Let us know in the comment section below!