If the results in this study generalize, neither constant collaboration nor constant isolation are good. You want people to be able to crib ideas from you in a professional setting. You also want them to have enough time to think up their own ideas.
I know you didn't ask for advice, but perhaps code-review and design-review is actually all your team needs? i.e. instead of the constant collaboration of pair programming, you work on slightly lighter weight interaction by having pairs of people work on closely related projects code-reviewing each other and having times where they bounce ideas off each other, but who ultimately work alone till they produce something the other can see. A half-day boundary of interaction (non-formalized of course) may be sufficient to allow for the degree of collaboration to be fruitful.
I know you didn't ask for advice, but perhaps code-review and design-review is actually all your team needs? i.e. instead of the constant collaboration of pair programming, you work on slightly lighter weight interaction by having pairs of people work on closely related projects code-reviewing each other and having times where they bounce ideas off each other, but who ultimately work alone till they produce something the other can see. A half-day boundary of interaction (non-formalized of course) may be sufficient to allow for the degree of collaboration to be fruitful.