Prerequisites: 4th-level genius.
While concentrating, you can scan for presences as a standard action. This reveals the presence or absence of thoughts from creatures with Intelligence scores of 1 or higher within 40 feet of you. This uncanny detection is a sense on its own, and reacts to creatures you couldn't otherwise perceive. This sense can penetrate barriers, but 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt blocks it.
When you use this ability, you immediately know the number of thinking minds in the area, but you do not determine their locations unless you can otherwise perceive the creatures in question.