A year or so back I stumbled across this article in a science magazine that had a theory that intelligence, or the capacity for learning and memory, was directly influenced by the amount of neurons in an organism's brain.

For the most part, one has to assume that natural genetics dictate the maximum or minimum amount of neurons an organism is born/hatched with, but if this theory is true, then would it not be possible for other species besides Humans to have higher intelligence?

If anyone knows the article I'm referring to, I'd very much appreciate it if you could point me in the right direction!