Influencing Factors and Mechanisms of the Barnum Effect in MBTI Personality Tests: A Mixed-Methods Study

This study adopted a sequential explanatory mixed-methods design to explore the existence, formation mechanisms, and influencing factors of the Barnum effect in the Myers-Briggs Type Indicator (MBTI) personality test, with 79 and 5 college students recruited for the quantitative and qualitative phases respectively. The results revealed three key findings: (1) The Barnum effect was significantly prevalent among participants, with no significant differences in its intensity based on gender or prior familiarity with the MBTI; (2) Female participants reported a significantly higher level of belief in the validity of personality tests than male participants; (3) Belief strength in personality tests positively predicted the intensity of the Barnum effect, explaining 61% of the variance in descriptive endorsement of vague personality descriptions. These findings reveal the cognitive bias underlying the public’s acceptance of MBTI results, provide empirical evidence for rationally viewing and using popular personality tests, and offer practical implications for intervening in the Barnum effect in personality assessment contexts.