The Wason selection task is a logical reasoning puzzle designed to test how people think about conditional statements. In the classic version, participants are shown four cards, each displaying a number on one side and a color on the other. They must determine which cards to flip to test the rule: "If a card shows an even number, then its opposite side must be red." This task highlights common errors in reasoning, as many people struggle to select the correct cards. The challenge lies in understanding the need to confirm the rule and check for violations, illustrating how human cognition can be flawed in logical reasoning scenarios.