Keeping an open mind (maintaining a state of mind where one is receptive to that which one is unaccustomed to) might be in some respect essential to the collaborative process.
As any successful collaboration is reliant upon the input from multiple individuals, no one person can ever know what form that input will take. Hence, remaining open minded about what others might contribute - be it a thought, perspective, skill, experience or character trait - increases the likelihood that contributions will received and that the most will be made of them (even if it is to critically debate and reject it). In contrast, closed mindedness could be said to lead to contributors and contributions being rejected out of hand with little if any consideration.
It may be that there are some very basic level shared understandings such as "It's good to talk", "It's good to explore via discussion", etc. Perhaps these generally, though maybe not always, get taken for granted without critical exploration.