Dhaka, March 29 -- Daniel Kahneman, a psychologist who pioneered theories in behavioural economics that heavily influenced the discipline, and won him a Nobel prize, has died at age 90.

Kahneman, who wrote bestselling book Thinking, Fast and Slow, argued against the notion that people's behaviour is rooted in a rational decision-making process - rather that it is often based on instinct.

Kahneman's employer, Princeton University, where the Israeli-American academic worked until his death, confirmed his death on Wednesday in a statement on its website.

"Many areas in the social sciences simply have not been the same since he arrived on the scene," Prof Eldar Shafir, a former colleague, said in a press release. "He will be greatly missed...