Intelligence has been defined in many different ways, including the abilities, but not limited to, abstract thought, understanding, self-awareness, communication, reasoning, learning, having emotional knowledge, retaining, planning, and problem solving.
There are many ways to determine someone's intelligence.
Britney's is a point higher than Beyonce's, yet people still say she's dumb. She's actually pretty smart and you can see that on the personal letters she used to post on her website.