Descriptive Decision Theory is a branch of decision theory that focuses on how people actually make choices, rather than how they should make them according to rational models. It examines the psychological, social, and emotional factors that influence decision-making processes, often revealing inconsistencies and biases in human behavior. This theory contrasts with normative decision theory, which prescribes ideal decision-making strategies based on logic and probability. By studying real-life decisions, Descriptive Decision Theory helps to understand phenomena like cognitive biases, heuristics, and the impact of framing effects on choices, providing insights into human behavior in various contexts.