At least for me, that's because you can focus with the knowledge that the background noise will never require your attention. The same is not true for open offi

At least for me, that's because you can focus with the knowledge that the background noise will never require your attention. The same is not true for open offices, which is where it breaks down for me. Any voice I hear could be trying to get my attention, and I have to pay attention to it in order to realize that it doesn't.