How do you know someone is smart?
The Dunning-Kruger effect causes less intelligent people to overestimate their abilities while highly intelligent people underestimate theirs, yet humans have evolved to judge others' intelligence reasonably well. Drawing on Reddit responses, the piece identifies eighteen behavioral markers of genuine intelligence, including intellectual humility (admitting what you don't know), adaptability (changing views with new evidence), clear communication tailored to your audience, and curiosity. Rather than displaying confidence or dominance, truly intelligent people tend to listen more than talk, ask thoughtful questions, and focus on getting things right rather than being right.