To me real intelligence is the ability to reason coherently. Humans, even when they are wrong, work in a way coherent with their prinicples/beliefs/axioms. Consider Sheldon from Big Bang Theory who does a very convincing job as a theoretical physicist, at least to the untrained ear, merely by memorising lines. However, as soon as he is questioned on something he didn't memorise, the act falls apart in a way a real Physicist wouldn't even in a domain he doesn't specialise in. For a trained ear, though, even during the act, the inconsistencies are audible.