I Should Have Known Better: Development of a Self-Report Measure of Gullibility.

The aim of this research was to explore the predictors of gullibility and to develop a self-report measure of the construct. In Studies 1 to 3, exploratory and confirmatory factor analyses were conducted on a large pool of items resulting in a 12-item scale with two factors: Persuadability and Insensitivity to cues of untrustworthiness. Study 4 confirmed the criterion validity of the scale using two distinct samples: scam victims and members of the Skeptics Society. Study 5 demonstrated positive relationships between gullibility and the self-reported persuasiveness of, and likelihood of responding to, unsolicited emails. Throughout the article, analyses of a variety of measures expected to converge with the scale provided evidence for its construct validity. Overall, these studies demonstrate that the construct of gullibility is distinct from trust, negatively related to social intelligence, and that the Gullibility Scale is a reliable and valid measure of gullibility.