Jul 03, 2025 12:30:00

Research results show that even today's young people are fooled by the 'Barnum effect,' which makes people believe personality tests that apply to everyone

The Barnum effect is a psychological phenomenon in which people assume that vague characteristics that apply to everyone in personality tests and fortune telling 'perfectly apply to me.' The Barnum effect is well known, and some people may think that fewer people would be fooled by it in today's world where information is easily available on the Internet and social media, but a paper published in 2025 by a psychologist at the University of Nantes in France showed that the Barnum effect may also lead young people today to easily believe vague personality tests and fortune telling.

Getting students interested in psychological measurement by experiencing the barnum effect.
https://psycnet.apa.org/record/2025-93651-009

Why You Might Not Want to Trust a Personality Test | Psychology Today
https://www.psychologytoday.com/us/blog/fulfillment-at-any-age/202507/why-you-might-not-want-to-trust-a-personality-test

The Barnum effect is a psychological effect named in 1956 by American psychologist Paul Meehl, after the famous American showman Phineas Taylor Barnum 's words, 'There is a gist that applies to everyone.' After conducting a psychological test on a subject, if you convey a 'quality that seems to apply to everyone,' such as 'You sometimes seriously wonder if you made the right decision or took the right action,' regardless of the test results, the subject will be fooled into thinking that 'this psychological test is appropriate.' This is the Barnum effect.

The Barnum effect is also known as the Forer effect. In a study conducted in 1949 by psychologist Bertram Forer , who is the origin of the Forer effect, on 39 students in a psychology course, students were given a fake psychological diagnosis and given feedback that could be applied to anyone. As a result, the students scored an average of about 4.26 on a scale of 0 to 5, which was considered to be very reliable. On the other hand, a paper published in 2002 by E. Scott Geller of Virginia Tech reported that a similar test aimed at the Barnum effect was rated an average of 3.6 on a scale of 1 to 10, and only a portion of students accepted it.

To see if people's tendency to believe false feedback changes, psychologists Corentin Gontier and Noémie Thomassin of the University of Nantes told students that they were taking a 30-item online test, which they told them was a 'validated, cutting-edge personality test.' 2,269 students participated in the test, and after receiving 'fake feedback aimed at the Barnum effect,' they rated the validity of the test on a 6-point scale from 0 to 5.

As a result, 85% of the students rated the test validity with a score of 4 or 5 (out of 5), with an overall average score of 3.59, concluding that the Barnum effect test is valid for today's young generation. Furthermore, 77% of the students responded that they would like to use the test in their future careers because it was highly valid, even before they were informed that the test was a false test based on the Barnum effect.

Another aspect that Gontier and Thomasson examined is the idea of using the Barnum effect as an educational tool. Psychometrics, the field of psychology in which Gontier and Thomasson specialize, is a field of psychology that uses numerical measurements of people's minds and behaviors, and is not a very popular topic for undergraduate students. However, the authors state that 'the 'cognitive conflict' created by questioning students' understanding of how tests work should help to actively engage students and change their preconceptions about their interest in psychometrics,' and argue that by having students experience the easily deceived Barnum effect, they may be more likely to become interested in psychometrics.

Susan Krauss Whitborn, Professor Emeritus of Psychology and Brain Sciences at the University of Massachusetts Amherst, points out two important points about the results of this study. First, from an educational perspective, stimulating students' imaginations may be an effective way to stimulate their motivation to learn, just as students who experienced the Barnum effect tended to be more immersed in class, even in academic fields that they are not very interested in. Not only in the field of education, but also in conversations with children or business meetings, if you find yourself continuing to discuss abstract points, Whitborn says that it would be effective to stimulate the discussion with powerful concrete examples.

Gontier and Thomason's research also suggests that the Barnum effect is still an easy psychological trap to fall into. 'The phenomenon known as ' confirmation bias ,' where we believe what we want to believe (the good things about ourselves) and ignore what we don't want to believe (the not so good things),' Whitbourne said. 'You need to be clever to discern the truth when it seems too easy to believe.'