I don't really know what to call it, actually.
When Johann and I argue (like all couples, no one's perfect) I realize that I'm not speaking to just one of the alters. The last time I asked him, "Which of you keeps coming out when we argue?" Yohann told me, "None of us. You're speaking to all of us. Together...like we would be if we weren't crazy." "But that's impossible, because you're all still separate. Someone has to be in control." "But it isn't. When a situation becomes drastic enough, if I'm feeling stressed enough, everyone gets pulled in to one place. You're not just speaking to one of us, you're just speaking to Johann [the physical body]."
Does this make sense to anyone?