The psychologist Daniel Kahneman, who has died aged 90, won the 2002 Nobel prize for economics despite describing himself as “mostly cheering … from the sidelines” of the subject. He achieved celebrity status in 2011 with the pop psychology book Thinking, Fast and Slow, at the age of 77 and after a lifetime of rigorous academic research. Such unpredictable events were typical of his long and eclectic career, while also provoking him to ask the myriad questions about human behaviour that formed the basis of his often counterintuitive theories. His work revealed the extent to which human beings make erroneous judgments in everyday situations and base decisions on those judgments. Steven Pinker called him “the world’s most influential living psychologist”.
From early in his career, working at the Hebrew University in Jerusalem, Kahneman had been interested in obtaining results that could be applied to real-world situations. One of his first insights came when he was trying to persuade flight instructors that reward was more effective than punishment when training people in new skills. A member of his class flatly contradicted him, saying that cadets he praised for a successful manoeuvre invariably did worse the next time, and those he reprimanded for fluffing a skill did better.
