The thing with science is that you can’t just accept things because they seem obvious. The scientific method exists for a reason. Sometimes things that look obvious turn out to be false, and sometimes proving an obvious thing to be true is a necessary first step to have a solid foundation from which to build other more nuanced hypotheses. Either way, the point is that studies aren’t all about finding some new and surprising conclusion. Sometimes they’re about taking something you were pretty sure of already, and making it into actual science.