You think "like" a genius is correct. You think "as" a genous is not. "Like" is always followed by a noun or pronoun. It is never followed by something that contains a verb. "As," on the other hand, is always followed by a clause (something that has a verb in it). Examples: "You think as a genious would" is correct. Would is a modal verb, so the correct word is "as," not "like." "You think as a genious thinks" is also correct. "Thinks" is a verb. "You think like me." is also correct. Why? The word "me" is a pronoun. I hope this helps. Rick