Sound in general makes it so hard to concentrate; human voices are worse. I suspect brains are built to pay attention to human voices, or at least mine seems to do so. Noise attenuating headphones don't help; they work ok at blocking out trucks but poorly on voices. Earbuds plus music do an ok job, but the studies I've seen show decreased performance when listening to music. Even if you think you aren't, part of your brain is paying attention. And really, why do I have to listen to music all day to drown out the noise of people.
And let's not forget visual distractions -- all the shit waving around in my field of vision doesn't help either.
Like I suspect many of you, I'm consistently far more productive late at night. In my case, that's because it's the only time I have where it's quiet and I'm left alone.
That being said, there is a lot of merit in having people interact with each other to cover issues and problems and ideas involved in the overall design of the product you're building.
I say this, because I have worked in a 16 person team open office, and while there was some adjustment to it, it was a pretty ok working environment. Right across the hall, the rest of the company worked in one big room. We were lucky that we were 'noisy enough' that we got our own team open-office, but the poor guys on all the other teams got to work in the so-called 'collaborative environment' where talking in groups was basically banned. It got nicknames like 'The Tomb' and (sarcastic) 'Happy-land'.
In teaching you talk about time on task, and how to get everyone in the classroom to focus on the work.
The open office environment can work in certain circumstances (roles) but if you are paying someone to focus on work, then provide them with an environment where they can focus on the work.
At least these days, ear phones that subdue external sounds are available and folks can usually figure out how to block visual distractions.
"Orbiting the Gaint Hairball" has a good example of someone setting up an office that is outside of corporate guidelines that serves the people that work in it.