It's nearly 20 years since I worked in an office with a door. Most of the time, that's been my choice. Even as CEO, I preferred to be where I could see people and they could see me. I liked tuning into the company mood, pace, and attitude. I wanted to make it clear that I was available and that I didn't expect anyone to work in conditions I wouldn't accept too.

I still believe all that. But when I went to hear Julian Treasure talk about the role that sound plays in business, I was worried by one statistic that he offered: Open plan offices, he said, are responsible for a productivity decline of up to 66%

According to the Institute of Interior Design, loud noise is the number one problem open offices face today.

That noise and distraction should prove so debilitating shouldn't have surprised me. Our brains aren't designed to multi-task and they can't do it. You can't follow two conversations at once. You can't write and think at the same time. You can task switch—swiftly and frequently—but between tasks there is always waste, loss of focus, and concentration.

So, what's better? The open plan spaces where it can be hard to pay attention to one thing at a time—but which do reinforce a sense of camaraderie and connectedness, or the protected offices where you can think but not, perhaps, communicate so well?

While the Institute of Interior Design frets over this problem, the truth is, of course, that most companies have outsourced it. You go to the office when you want to connect with your colleagues. You stay home when you need to concentrate. Two offices for the price of one. But I'm left wondering whether that's a solution or just a different problem.