“I see myself described accurately in vague and generic descriptions of personality."
The Barnum effect is a cognitive bias that induces an individual to accept a vague description of personality traits as applying specifically to themselves. . This bias is especially evident when the description contains gratifying elements while being vague and general, in other words, when the ideas expressed could apply to a large majority of people. The Barnum effect may persist even after one is made aware of the generic nature of the description .
"You need to be loved and admired, and yet you are critical of yourself. You certainly have weak points in your personality, but you generally know how to compensate for these shortcomings. At times you are very outgoing, talkative and sociable, while at other times you are introverted, wary, and reserved" . Did you recognize yourself in this portrait? If so, you have just experienced the Barnum effect. It is common for this effect to occur when reading a horoscope or numerology result, for example. Even knowing that this portrait is intended for a large audience, it can be disturbing to find that we identify with it precisely.
Although the interpretation of the Barnum effect was initially attributed to the excessive gullibility of individuals , contemporary explanations differ. Because the statements are sufficiently vague and generic, you will spontaneously supplement them with your own thoughts and experiences . For example, if the statement says, "you are a generous person," your brain will automatically try to associate that flattering statement with a specific example from your life experience. By interpreting the information and completing it in your own way, you validate it and thus strengthen your belief in the statement, as well as in the source that delivers it. Furthermore, the Barnum effect can be enhanced through the confirmation bias, which is the tendency to give more attention and weight to data that supports our preconceptions and beliefs than to those that contradict them. For example, if you believe in astrology and read your horoscope, you will tend to seek to connect its content to specific personal experiences, and to ignore content that might contradict it.  It has also been shown that positive and flattering statements, even if they are approximate or false, are more easily accepted as an accurate description of one’s personality than negative statements . Rather than the objective correctness of the statement, it would seem to be the desire for the statement to be true that elicits adherence to it.
The Barnum effect is generally manifested in areas such as astrology, clairvoyance, graphology, mentalism and fortune-telling. Although this bias does not usually have significant consequences, it can be exploited (dishonestly or not) to manipulate others, to prompt subscription to paid analyses or services, or to promote adherence to projects and beliefs. More subtly, the Barnum effect can also be exploited in the marketing and advertising industry. If consumers recognize themselves in the description of the "kind of people" who would benefit from a product, or if they recognize their situation in that of a "specific problem" for which it is possible to buy a solution, then they are more likely to buy into, and to be loyal to, that company or product. Thus, through the Barnum effect, the same generic description, written in such a way as to appear specific to the majority of people, can engender the wide acceptance by a large number of consumers at the same time.
Thoughts on how to act in light of this bias
When you find yourself believing dubious information about your personality traits, take a step back and wonder if that information would as easily apply to many other people.
Before making a major decision based on an analysis that we think is precise and personalized, check its scientific foundations and question the intentions of people who could have an interest (political, monetary, etc.) in making us adhere to their discourse.
How is this bias measured?
This bias was demonstrated by the American psychologist B. Forer in 1948 , during an experiment on his students. After giving them a personality test to complete, he gave each one a personalized individual analysis and asked them to rate its accuracy on a scale of 0 (poor) to 5 (excellent). A strong mean of 4.26 was obtained. However, the portrait, created from different horoscopes, was in fact identical for all participants. This experiment has since been repeated many times, with consistently similar results . It has been found that the assessment of the relevance of the profile increases if the person is convinced that the analysis is personalized .
This bias is discussed in the scientific literature:
This bias has social or individual repercussions:
This bias is empirically demonstrated:
 Furnham, Adrian & Sandra Schofield (1987). Accepting personality test feedback: A review of the Barnum effect. Current Psychology 6(2): 162-178.
 Ulrich, Roger E., Thomas J. Stachnik & N. Ransdell Stainton(1963). Student acceptance of generalized personality interpretations. Psychological Reports 13(3): 831-834.
 Forer, Bertram R. (1949). The fallacy of personal validation: a classroom demonstration of gullibility. The Journal of Abnormal and Social Psychology 44(1): 118.
 Dickson, D. H. & Ivan W. Kelly (1985). The ‘Barnum Effect’ in personality assessment: A review of the literature. Psychological Reports57(2): 367-382.
 Fichten, Catherine S. & Betty Sunerton (1983). Popular horoscopes and the “Barnum effect”. The Journal of Psychology 114(1): 123-134.
Individual level, Representativeness heuristic, Availability heuristic, Need for self-esteem, Need for cognitive closure
Synonyms : Forer effect, Subjective validation effect
Charlotte Remy, PhD candidate in medical physics at the Université de Montréal.
Translated from French to English by Susan D. Renaud.
How to cite this entry
Remy, C. (2021). Barnum effect. In C. Gratton, E. Gagnon-St-Pierre & E. Muszynski (Eds.). Shortcuts: A Handy guide to cognitive biases Vol. 4. Online: www.shortcogs.com