You sense the presence of thinking creatures around you. You detect the presence or absence of thoughts from conscious creatures that have Intelligence modifiers of –3 or higher. You can choose to ignore the thoughts of creatures you're familiar with so they don't interfere with your detection of other thoughts. The spell can penetrate some barriers, but 3 feet of dirt or wood, 1 foot of stone, 1 inch of metal, a thin sheet of lead, or any force barrier blocks it. Creatures who are immune to mental effects are immune to detection by this spell.