If you believe in the paradigm illustrated here, (also known as the Dunning-Kruger Effect), it doesn’t take long to separate the informed from the uninformed.
Possibly the smart from the stupid, too.
Simply listen to the quality and frequency of questions asked. Keep a weather-eye for people who lead with certainty. Identify those who listen from those who don’t.
That’ll often tell you everything you need to know about a person.