David Keirsey builds personality in a series of concentric rings – like an onion, with the inner rings affecting the outer. It builds to 16 different personality types and has similarities with the Myers-Briggs (MBTI) model. The 2 inner rings constitute a person’s temperament and are unchanging through life according to Keirsey. They offer a very practical and informative perspective. Are you an Artisan, Guardian, Rational or Idealist?