What is barnum effect?
This is a cognitive bias that occurs when you believe that generic personality descriptions and statements apply to yourself. In reality, the description is general and vague enough to apply to almost everyone.
Example in the hiring process.
In personality tests, the results are oftentimes presented in a very general way, having both pros and cons. By applying very general wording to test results it is easier for candidates to recognise themselves in the results. This is also why personality tests and horoscopes are oftentimes mentioned in the same sentence when speaking about the Barnum Effect.