My two bits here are that writing is a solitary job but there are times when one needs to discuss the work, and see what's working and what's not.
I used to wish I could write songs like the others - and I've tried but I just can't. I get the words all right, but whenever I think of a tune and sing it to the others they always say 'Yeah, it always sounds like such a thing' and when they point it out I see what they mean. But I did get a part credit as a composer on one - it was called What Goes On.
There's nothing like having a sympathetic reader who asks the right questions, who understands what you're trying to achieve and only wants to make it better.
So we can sit with Lee Unkrich and Andrew Stanton, and all the other folks and experience what the film is going to be like. And then we go away into a room, and we talk about what worked and what didn't. And then we take all of those findings and we do that whole process again.
Get five or six of your smartest friends in a room and ask them to rate your idea.
In the best possible scenario, whenever you get notes from people, they're good notes, and they see things that you wouldn't have seen otherwise, and they make you a better writer.
A key part of the process for me is having screenings: not official test screenings, just gatherings of people, some I know and some I don't. We ask what is working and what isn't. So it's not as if I'm shutting out input.
We tend to read each other's books in sizeable chunks as they are written. I don't know that you could say we are ruthless with each other - in fact, I suppose we are very kind. There are ways to make suggestions which are not destructive.