Complex sentence: Implicit personality theory (IPA) concerns the general expectations that we build about a person after we know something of their central traits, for example when we believe that a happy person is also friendly, or that quiet people are shy.
Split into simpler sentences: Implicit personality theory (IPA) concerns the general expectations that we build about a person after we know something of their central traits. For example, when one believes that a happy person is also friendly, or that quiet people are shy.