“Another trait, it took me a while to notice. I noticed the following facts about people who work with the door open or the door closed. I notice that if you have the door to your office closed, you get more work done today and tomorrow, and you are more productive than most. But 10 years later somehow you don't know quite know what problems are worth working on; all the hard work you do is sort of tangential in importance. He who works with the door open gets all kinds of interruptions, but he also occasionally gets clues as to what the world is and what might be important. Now I cannot prove the cause and effect sequence because you might say, ``The closed door is symbolic of a closed mind.'' I don't know. But I can say there is a pretty good correlation between those who work with the doors open and those who ultimately do important things, although people who work with doors closed often work harder. Somehow they seem to work on slightly the wrong thing - not much, but enough that they miss fame.”
Notice that Hamming takes it for granted that everyone has an office; the only question is "office with closed door, or office with open door?".
This is a very different question from "offices or open plan?".
(My own preference is one I've seen others express here: rooms for groups of roughly 4-10 people, private rooms for intense concentration and private meetings, and some communal space.)
That was the rule in the Physics department I spent a little time in. 'Tea' involved about 40 researchers in a large room on couches and armchairs arranged (and rearranged) in small groups. You were expected to share problems, findings, ideas, and listen. Room had no blackboards but plenty of paper napkins.
Broke up around 4pm most days but sometimes went on much longer.
Leaders used to hear a problem and say things like "talk to Robin. He's been working on conditionally convergent series", so you did, and it helped.
– Richard Hamming, “You and Your Research” http://www.cs.virginia.edu/~robins/YouAndYourResearch.html