What branch of psychology deals with the Framing Effect?
Gestalt psychology (Interpretrations of problems) and cognitive psychology (Problem solving). If you are fairly new to these topics, Robert Stenberg's &quot;Cognitive Psychology&quot; is pretty simple and explains a lot of the basics of this complicated issue.
It should be noted that Tversky and Kahneman are specialist in cognitive psychology itself, and have more works on this subject; but I still recommend Stenberg's work to appreciate a lot more of these books if you are starting to learn in psychology and the likes.
Hope it helps.