Claudius Galenus was a Greek philosopher and physician known in the psychology world as the founder of the Four Temperaments of Personality. This philosophy is part of the approach known as Humourism originating from the Greek philosopher Empedocles who implied that all things are combinations of the four basic elements: earth, water, fire and air. Empedocles believed that different qualities of the basic elements would explain the existence of all substances on earth.
Earth: cold and dry
Air: warm and wet
Fire: warm and dry
Water: cold and wet
Hippocrates known as the founder of modern medicine, stated that the qualities of the four elements are reflected in our bodily fluids namely blood, phlegm, yellow bile and black bile.
Galen explored this the approach of Humourism further, expanding into a theory of personality. Galen saw a direct relationship between the levels of the humours in the body and the emotional and behavioral inclinations known as temperaments. He described these temperaments as sanguine (blood), phlegmatic (phlegm), choleric (yellow bile) and melancholic (black bile). Imbalances in the humours determined personality as well as susceptibility to certain illnesses.
If one of the humours developed uncontrollably, becoming obviously dominant to the other three humours, the corresponding personality type would also become dominant. As a paradigm, a sanguine person has too much blood and as a result shows characteristics such as cheerfulness and optimism but can be selfish and overconfident. A phlegmatic person suffers from too much phlegm and would be rational and consistent but often slow and quiet. A choleric person suffers from too much bile and would be passionate and energetic but could also be tempered. Finally, a melancholic person suffers from excess bile and would be characterised as the artists, poetic and artistic but often depressed and fearful.
During Galen’s time, the Medieval Ages and up until the Renaissance it was considered accurate that certain people were born predisposed to one of the four temperaments and imbalances could be cured by changes in diet, exercise or the extremes of purging and blood-letting. By the 1500s, hundreds of errors were found in Galen’s work but he would later come to influence Hans Eysenck that concluded that temperaments are in fact biologically based but not through humours. Eysenck identified two personality traits he called neuroticism and extraversion, a nod to Galen.
Collin, Catherine. The Psychology Book. New York: DK Pub., 2012. Print.