Renowned psychologist Daniel Kahneman, who revolutionized the field of economics with his insights into decision-making biases, passed away at the age of 90. Alongside his collaborator Amos Tversky, Kahneman challenged the traditional notion of humans as rational actors capable of making clear choices. Their research, detailed in Kahneman's best-selling book "Thinking, Fast and Slow," revealed how subconscious quirks and mental shortcuts can distort our thoughts in predictable yet irrational ways.

One example from Kahneman's book described an Israeli army challenge that assessed future leadership potential. Despite confidently identifying leaders-in-the-making during the challenge, observers were surprised to find that their assessments did not align with the soldiers' performance at officer training school. This led Kahneman to coin the term "the illusion of validity" to describe this cognitive phenomenon.

Kahneman and Tversky's groundbreaking work on decision-making, particularly their theory of loss aversion, laid the foundation for behavioral economics. In 2002, Kahneman received the Nobel Prize in economics for his contributions, with economists noting that Tversky would have likely shared the prize had he not passed away in 1996.

Professor Kahneman, who never took an economics course, employed his psychological background to advance behavioral economics, rethinking issues in fields ranging from medical malpractice to baseball talent evaluation. His work emphasized the importance of understanding and overcoming inherent biases in decision-making for personal and societal benefit. Kahneman's legacy as a pioneer in the field of behavioral economics continues to influence how we approach decision-making in various aspects of life.