How do they know?

We recently gave Adam his first Oreo cookie. He's not much of a sweets eater, so we didn't think he'd even try it, much less eat the whole thing. We were both thinking he'd probably just bite into the whole thing, but NOPE. He pulled the two cookies apart and started licking out the inside! JUST LIKE ME! Can the way a person eats an oreo be pre-genetically determined?