Herrmann describes an inter-connection between the four quadrants and a preference or dominance of one or more of the thinking quadrants in all of us. Just as our arms, hands or eyes become dominant through use, Herrmann felt our brains take on quadrant dominance through use or disuse. With a clear understanding of what preferences we have, Herrmann felt we could better develop our "whole brains." His HBDI inventory was developed as a tool to better understand our thinking preferences.
New research since the time of Herrmann's experiences indicates the picture of dominance is not as clear cut or simple as once believed.