Gullibility: a review of the literature and devising a self-report measure

Gullibility refers to a vulnerability to being manipulated. Although almost 300,000 people in the United States of America in 2014 fell victim to various scams (Federal Bureau of Investigation Internet Crime Complaint Center, 2014), this area is surprisingly under researched. The dissertation begins with a review of the empirical literature, drawing together findings from research on the Barnum Effect, superstition, social vulnerability, scam compliance, trust, social intelligence, deception detection, and Theory of Mind. The review concludes by arguing that insensitivity to signs of untrustworthiness may be central to understanding the propensity for gullibility. Following the review, two empirical studies describe the development of a self-report measure of gullibility. In Study 1 (N = 371), a pool of items were generated and administered in an anonymous online survey. Demographic items and a measure of social desirability were also administered. An exploratory factor analysis produced a 35-item scale consisting of four factors labelled Persuadable, Trust, Unassertive, and Unsuspecting, which were not related to social desirability. In Study 2, a confirmatory factor analysis was conducted using a new sample (N = 325). Respondents completed the Gullibility Scale as well as measures of trust, agreeableness, Machiavellianism, and social intelligence. On the basis of the confirmatory factor analysis, the Trust factor was removed, which reduced the measure to a reliable 24-item scale, consisting of three factors. The Gullibility Scale had a moderate negative correlation with social intelligence and a weak positive correlation with agreeableness. The utility of this new self-report measure of gullibility for research and applied contexts is discussed.