Understanding Dark Traits and Manipulation Through Research: The Dark Triad, Machiavellianism, Gaslighting and the Seven Deadly Sins
What is the Dark Triad of narcissism, Machiavellianism and psychopathy, and how does gaslighting work? Where did the seven deadly sins come from? Organised with personality and sociological research, with a focus on protecting yourself rather than labelling others.
Last reviewed 2026-09-29
If someone is threatening or controlling you right now, don’t face it alone. Contact your local emergency number or a domestic abuse helpline.
Instead of “dark psychology”
Online, “dark psychology” is sometimes sold as secret techniques for manipulating people. In psychology, though, the topic is studied to understand harmful traits and behaviour so that harm can be reduced. Here is what that research says.
The Dark Triad: traits everyone has a little of
Paulhus and Williams (2002) grouped three overlapping yet distinct traits as the Dark Triad.
- Narcissism: a sense of being special and a strong need for admiration.
- Machiavellianism: a cynical, strategic willingness to use others for one’s goals.
- Psychopathy: impulsivity and a lack of empathy and guilt.
Importantly, these are not diagnoses you either have or don’t, but continuous traits everyone has to some degree. Researchers measure them with short questionnaires (Jones & Paulhus, 2014), and higher scores have been linked to aggression and unethical behaviour (Furnham, Richards & Paulhus, 2013). That doesn’t mean research supports labelling the people around you “psychopaths.” If you’re curious about narcissistic tendencies, you can look at yourself first with OIYO’s narcissism test.
Machiavellianism: from The Prince to a questionnaire
The name comes from The Prince (published 1532) by the 16th-century Florentine political thinker Machiavelli, a book famous for advising that a ruler must sometimes set morality aside to keep power.
The psychologists Christie and Geis (1970) built the Mach-IV questionnaire from lines in The Prince, measuring Machiavellianism by how much people agree with statements like “The best way to handle people is to tell them what they want to hear.” High scorers tended to be less swayed by emotion and to secure more gains in lab bargaining games.
Gaslighting: control that unsettles your sense of reality
The word “gaslighting” comes from Patrick Hamilton’s play Gas Light (1938) and the 1944 film based on it. A husband secretly dims the house’s gas lamps and, when his wife notices, insists she is imagining things until she doubts herself.
The sociologist Sweet (2019) analysed gaslighting not just as an individual psychological problem but as a form of control that exploits power imbalances and social stereotypes such as “women are emotional” to break down the other person’s sense of reality. She also noted that it often appears alongside domestic abuse.
Signs that can help you notice it:
- Your memories or feelings are repeatedly denied: “That never happened,” “You’re too sensitive.”
- After conversations you always end up apologising and find it hard to trust your own judgement.
- You are nudged to cut back contact with friends and family.
If you see these signs, keep records and talk to someone you trust or a specialist service. The harder it is to judge alone, the more an outside view helps.
The seven deadly sins: an old list, modern psychology
The seven deadly sins — pride, greed, lust, envy, gluttony, wrath and sloth — come from the “eight evil thoughts” listed by the 4th-century monk Evagrius, which Pope Gregory I reorganised into seven in the 6th century.
Psychology today studies these emotions as things to understand rather than as sins. For example, envy arises mainly when someone similar to us has what we want (Smith & Kim, 2007), and research distinguishes “malicious envy,” which makes us want to pull the other person down, from “benign envy,” which makes us try harder ourselves (van de Ven, Zeelenberg & Pieters, 2009). What matters is less the feeling than what we do with it.
Summary at a glance
| Topic | What research says | Watch out for |
|---|---|---|
| Dark Triad | Continuous traits everyone has | Don’t label others with them like diagnoses |
| Machiavellianism | Measured by the Mach-IV, based on The Prince | A high score ≠ a criminal |
| Gaslighting | Control that exploits power imbalances | Keep records; seek outside help |
| Seven deadly sins | A list from medieval monastic tradition | Actions matter more than feelings |
References
- Paulhus, D. L., & Williams, K. M. (2002). The Dark Triad of personality: Narcissism, Machiavellianism, and psychopathy. Journal of Research in Personality, 36(6), 556–563.
- Jones, D. N., & Paulhus, D. L. (2014). Introducing the Short Dark Triad (SD3): A brief measure of dark personality traits. Assessment, 21(1), 28–41.
- Furnham, A., Richards, S. C., & Paulhus, D. L. (2013). The Dark Triad of personality: A 10 year review. Social and Personality Psychology Compass, 7(3), 199–216.
- Machiavelli, N. (1532). Il Principe (The Prince).
- Christie, R., & Geis, F. L. (1970). Studies in Machiavellianism. Academic Press.
- Hamilton, P. (1938). Gas Light (play). Constable.
- Sweet, P. L. (2019). The sociology of gaslighting. American Sociological Review, 84(5), 851–875.
- Smith, R. H., & Kim, S. H. (2007). Comprehending envy. Psychological Bulletin, 133(1), 46–64.
- van de Ven, N., Zeelenberg, M., & Pieters, R. (2009). Leveling up and down: The experiences of benign and malicious envy. Emotion, 9(3), 419–429.