Gary Klein

Gary A. Klein is a cognitive psychologist whose research has reshaped the study of how experts make decisions in real-world conditions. He is a Senior Scientist at MacroCognition LLC, the research firm he founded, and was previously Chief Scientist at Klein Associates, the cognitive science consultancy he ran for over two decades. His work pioneered the field now known as Naturalistic Decision Making (NDM), a research program that studies expert decision-making outside the laboratory, in operational settings where stakes are real and consequences are immediate.

Klein earned his PhD in experimental psychology from the University of Pittsburgh. His early work was conducted in collaboration with the U.S. Army Research Institute and other military and government research programs, where he studied how firefighters, military commanders, intensive care nurses, and pilots make consequential decisions under conditions of time pressure, uncertainty, and incomplete information. His method was direct field observation supplemented by Critical Decision Method interviews, a structured protocol for reconstructing the cognitive processes used in actual operational events.

His central empirical finding, developed across decades of field studies, is that expert decision makers rarely select among options by comparing alternatives. They typically recognize a situation as familiar, retrieve a course of action from past experience, mentally simulate it for adequacy, and either execute it or revise it. This Recognition-Primed Decision (RPD) model has become foundational in operational training, military command and control, emergency response, and increasingly in the design of decision-support systems including AI. The model has been validated in fire command, surgery, electronic warfare, neonatal intensive care, and chess.

His 1998 book Sources of Power: How People Make Decisions synthesizes his early research for general audiences and remains the standard reference in the field. The Power of Intuition (2003) translates the findings into practical guidance for operators. Streetlights and Shadows (2009) examines the limitations of conventional decision research. Seeing What Others Don't (2013) extends his framework to the cognitive processes underlying insight. His applied work has shaped training programs in the U.S. military, NASA, the FBI, and major fire and emergency services, and continues to influence how AI decision-support tools are designed and evaluated.

Gary Klein's work grounds Ambiguity Is Wisdom. The treatise cites Sources of Power as evidence that expert decision-making does not seek binary answers; experts seek information that helps them understand the situation's complexity. The principle operationalizes this insight: AI must provide evidence for sensemaking, not conclusions that replace it.

Klein's body of empirical research on how experts actually make decisions is the strongest available case for the design implication the principle draws. Decision-support systems that compress information into a single recommendation strip out the situational nuance that experts depend on. Systems that surface uncertainty, alternatives, and context provide the raw material that the Recognition-Primed Decision process actually uses. The principle's directive, "reveal the probabilities," has its empirical support in three decades of his field studies on what high-stakes expertise looks like in practice.