The Barnum or Forer Effect is a psychological phenomenon where individuals believe vague, general statements about personality are highly accurate for them personally. This effect is named after P.T. Barnum, who was known for his ability to appeal to a wide audience, and Bertram Forer, who conducted a study in 1948 demonstrating this effect. In his study, Forer gave participants a personality test and provided each with the same generic feedback, which they rated as highly accurate. This effect explains why people often find horoscopes, fortune-telling, and personality tests compelling, as they tend to accept information that could apply to many people as uniquely applicable to themselves.
In my college, I had worked on a demo app for this: