It's my opinion based on years of experience working in the field with users and stakeholders. If you are skeptical about how a certain design affects users you should go do research on that. This way, you have substantial basis for your doubt instead of doubting because of "lack of research" which is no basis at all. A "lack of research" doesn't disprove a claim, only research or experience that goes against the claim does.

What you're saying when you need research to understand user behavior is that you have no experience working with users, and you're not sure if users behave this way because you probably wouldn't. If this is the case, I suggest you go get experience with actual users. You'd be surprised how a design aspect you expect them to understand throws them off. And you'd eventually learn that you are not the user and using yourself as the standard to judge how users behave is not usually accurate. Go get experience with users.