Iowa Gambling Task

The Iowa Gambling Task is a psychological test developed by Antonio Damasio and colleagues to demonstrate the role of emotion in decision-making. Participants draw cards from four decks. Two decks yield high immediate gains but larger occasional losses (disadvantageous in the long run); two decks yield smaller gains but smaller losses (advantageous). Healthy participants gradually shift to the advantageous decks, not because they can explicitly calculate the expected values, but because they develop anticipatory skin conductance responses—a gut feeling of anxiety—before choosing from the risky decks. This pre-conscious emotional signal guides their behavior before conscious knowledge does.

Patients with damage to the ventromedial prefrontal cortex fail this task catastrophically. They continue to choose from the risky decks even after they can verbally describe which decks are dangerous. They know but they do not feel, and therefore they cannot act. The task is not a measure of rationality; it is a measure of whether cognition and affect are properly coupled.