The Somatic Marker Hypothesis (SMH) proposed by A. R. Damasio has brought forward a new framework for understanding our decision-making based on the latest findings of neuroscience, and holds that emotion is an essential factor in any decision-making. However, the “Iowa Gambling Task” (IGT), which is the evidence to confirm the hypothesis, has unclear points about how to interpret its results. The present paper makes clear the interpretative problem of the IGT results, suggests some additional tasks to solve the problem, and then, clarifies the contents of SMH.