Main article: Machiavellian intelligence
Machiavellianism is also a term that some social and personality psychologists use to describe a person’s tendency to deceive and manipulate other people for their personal gain. In the 1960s, Richard Christie and Florence L. Geis developed a test for measuring a person’s level of Machiavellianism. This eventually became the MACH-IV test, a twenty-statement personality survey that is now the standard self-assessment tool of Machiavellianism. People scoring above 60 out of 100 on the MACH-IV are considered high Machs; that is, they endorsed statements such as, “Never tell anyone the real reason you did something unless it is useful to do so,” (No. 1) but not ones like, “Most people are basically good and kind” (No. 4). People scoring below 60 out of 100 on the MACH-IV are considered low Machs; they tend to believe, “There is no excuse for lying to someone else,” (No. 7) and, “Most people who get ahead in the world lead clean, moral lives” (No. 11). Christie, Geis, and Geis’s graduate assistant David Berger went on to perform a series of studies that provided experimental verification for the notion of Machiavellianism.
Machiavellianism is one of the three personality traits referred to as the dark triad, along with narcissism and psychopathy. Some psychologists consider Machiavellianism to be essentially a subclinical form of psychopathy, although recent research suggests that while Machiavellianism and psychopathy overlap, they are distinct personality constructs.
In 2002, the Machiavellianism scale of Christie and Geis was applied by behavioral game theorists Anna Gunnthorsdottir, Kevin McCabe and Vernon L. Smith in their search for explanations for the spread of observed behavior in experimental games, in particular individual choices which do not correspond to assumptions of material self-interest captured by the standard Nash equilibrium prediction. It was found that in a trust game, those with high MACH-IV scores tended to follow homo economicus’ equilibrium strategies while those with low MACH-IV scores tended to deviate from the equilibrium, and instead made choices that reflected widely accepted moral standards and social preferences.
Machiavellianism has been found to be negatively correlated with the Agreeableness (r = -.47) and Conscientiousness (r = -.34) dimensions of the Big Five personality model (NEO-PI-R).