Psychology often plays a major role in matching people to suitable professions. John Holland’s Occupational Themes, also known as the Holland Codes, identify six vocational personality types: Realistic (Doers), Investigative (Thinkers), Artistic (Creators), Social (Helpers), Enterprising (Persuaders), and Conventional (Organizers). Using these categories, you can explore careers that are a better fit with your personality and values.