The backstory on this is that one of the persistent pains for this team is a disconnect with QA, so the team agreed to shift their working pattern (culture) to incorporate QA as a direct part of the team, with a much more prevalent role related to work in the current iteration.
What the team knew was that this should give them much shorter feedback loops on if something needed to be fixed or not, and it should also greatly shorten the amount of time that the project would go dark in QA at the end of an iteration/release.
What teams experienced with multiple roles working together know about this closer collaboration is the fact that when you have close association with the work that a specific role is doing on a day to day basis, you learn about that role to the point where you naturally take on some of their work.
Rather than trying to communicate to the team every single advantage to having all of the roles working together closely, I kept the focus on the direct pain the team was trying to address. I knew that sooner or later the secondary effect of role "spreading" would happen, but not when.
The following picture is a screen shot of a conversation that took place between one of the UX designers on the project (Val G) and one of the developers on the project (Thomas H). I was impressed enough at how fast the team shifted their culture to realize this secondary benefit of close collaboration that I thought it warranted a blogging.
Here's the conversation: