There was an interview of Jony Ive not long ago in which he talked about Apple's product design process. He said this process starts with one or two people having an abstract idea; this first step usually doesn't involve much collaboration. The abstract idea then gets turned into a physical prototype. Collaboration really takes off as the prototype is made and refined.
Ive has repeatedly noted the fragility of new ideas. You don't want team members to just say "no" to ideas -- "what if we did this?" is generally better than "no."
I used to work as a trial attorney, and have seen the tactical benefits of getting jurors to take an early fixed position. A person who takes an early yes/no position is normally reluctant to change his mind later -- no one wants to admit his initial judgment was wrong. That's why opening statements at trial are so important: my goal with opening statement was to get jurors "rooting for" my side of the case early, and to keep jurors on my side as long as possible. I sequenced trial testimony to delay the presentation of evidence that hurt my case but had to be addressed, knowing that the sooner jurors started rooting for me, and the longer they rooted for me, the less likely they'd change positions when I had to address case weaknesses.
So the key is to keep people from spiking new ideas too quickly -- get people saying "what if we did this?" or "what if we changed this?" instead of taking a fixed "no" position that will be difficult to change later.
I also thought it was striking how Jony Ive emphasized that collaboration worked best in conjunction with a prototype. So with product development, there may be significant collaborative benefits to turning abstract ideas into physical objects. Prototypes foster collaboration by giving team members a clear focal point and something to rally around. It's also hard to say "no" to the creation and improvement of a prototype -- team members are almost forced to constructively solve problems the prototype presents.
The author owns stock shares of Apple.