I did read some research about concentration and the effect of distractions. On average it takes 5 minutes to fully concentrate on a task. If you are distracted in the course of the task, it can take a further 5 minutes to regain the concentration and continue the task. Imagine if you are continually distracted, how long it takes to complete a task!
I think this shows that an office environment where there are distracting individuals is not conducive to work as it can be difficult to attain a sufficent degree of concentration. I find that when the office is empty in the early morning or later in the evening, or one individual in particular is absent, I get a lot more work done. Alot of people I speak to find this to be the case in their own workplaces.