I think pretty much everyone understands that much mental processing occurs at an unconscious level, without us even being aware of it. Who hasn't gone into a crowded bar and suddenly sensed "Uh-oh, there's going to be trouble tonight." Some call it intuition, some sixth sense, but there's nothing paranormal about it; the mind is thinking all the time, and constantly gathering subliminal data, perhaps not completely effectively or accurately, but it is continuously making judgements and and evaluating clues without our knowledge. It makes decisions based on inconclusive data and more often than not (but not always!) it is right.

Haven't you ever suddenly thought "I don't trust this guy", or, "I'm walking into an ambush here", or "This dude's bluffing, he didn't draw that fourth queen." Sometimes the signal is very strong: "This guy's lethal, don't let him get between you and the door."

We pick up on a lot without knowing, and we rely on crude statistical calculations of chance all the time. Evolution taught us this a long time ago, when the forest was too quiet, when the waterhole seemed too peaceful. The trick is to rely on this skill when you have no other alternative, and to resist the temptation to use it when you do. I trust my intuition, I know it is not infallible, but I consult it frequently.

Remember, the definition of intelligence is the ability to make good decisions based on insufficient information.