VOICE TESTING by Jan Forster
Beyond the fact that with only 3 cards, you have at LEAST a 33% chance of being right, (heck 1 in 3), can this be made more convincing by increasing the number of cards? If there were say, 20 cards, and you were then able to say exactly what it was the first time, then that would be much greater than chance alone & indeed be much more convincing.