Those who are fond of reading horoscopes tend to fall victim to the Barnum Effect. Even though the descriptions or descriptive terms used in the inventories, typologies, and tests can apply equally well to other people, some individuals are gullible enough to believe they are unique to themselves.
"Barnum statements" are the bread and butter of psychics and palm readers. In fact, there is no better way to make a complete stranger believe that you know and understand them quite well.
Some of the examples of Barnum statements include:
“While you have some personality weaknesses, you are generally able to compensate for them."
"You have considerable unused capacity that you have not turned to your advantage.”
Obviously ambiguous, individuals nonetheless attach personal meanings to them.
At a psychological level, the big driver behind the Barnum effect is confirmation bias. (Theorypedia: Confirmation bias theory) Barnum statements are vague and generally positive statements about one's self.
The ingrained desire of confirmation bias to "remember the hits and forget the misses" about ourselves primes us to believe Barnum statements and fall prey to the Barnum Effect.