Either way, I think collaboration-oriented pedagogies recognize the importance of not assuming students already understand what it means to collaborate, and what quality collaboration looks/feels like.
As several have already mentioned, true collaboration is not simply throwing students together on a project that could have been done by students independently. Unfortunately, I think that is how most students think of "group projects."
Therefore, projects need sufficient expectations, structure, and scaffolding, to make it clear to students that they are interdependent.
Two articles I particularly like on this subject are:
Pedagogies of engagement: classroom-based practices
KA Smith, SD Sheppard, DW Johnson, RT Johnson - Journal of Engineering Education, Jan 2005
Turning Student Groups into Effective Teams
B Oakley, RM Felder, R Brent, I Elhajj - Journal of Student Centered Learning, V2 No1 2004