Different Personality types work and communicate in very different ways. Learning how to identify and understand them is a key component to successful relationships of all types.
Four types was originally called the four temperaments by Hippocrates and established the four archetypes of people’s personalities. The archetypes are not set-in-stone descriptions of people’s personalities, but often—once identified—we recognize these dominant traits in ourselves and others which deepens our understanding of why we do the things we do, and why other people might do things entirely differently.
Like any assessment tool—take only what resonates and is beneficial and leave the rest.