Dark Triad and Dark Tetrad

The dark triad, a popular concept in psychology, consists of three callous-manipulative personality types. They are: narcissism (lack of empathy, inflated self-importance, entitlement, need for admiration and attention), Machiavellianism (exploitation and manipulation of others, amoral, deceitful), and psychopathy (antisocial behavior, poor impulse control, selfishness, callousness, lack of remorse). While conceptually separate, they share traits: a short-term and exploitative mating strategy, impulsivity, low self-control, risk-seeking behavior, future-discounting, aggression, and selfishness. The concept and term were created by researchers Delroy L. Paulhus and Kevin M. Williams in 2002. 

The dark tetrad — an expansion of the dark triad — adds sadism (pleasure or gratification derived from inflicting on others physical or verbal pain, suffering, humiliation). In 2013, researchers Erin Buckles, Daniel Jones, and Delroy L. Paulhus, who coined the term, saw a correlation of sadism with the dark triad types. Researchers study the dark tetrad to understand the darker side of human personality, which can influence behavior in  work, relationships, risk-taking, and criminal behavior.