Kahneman was born in Tel Aviv in 1934. He spent his early childhood in France, returning to Israel in 1946.He studied Psychology and Mathematics at Hebrew University, Jerusalem and later (1961) obtained a PhD from the University of California.
In 1955 Kahneman joined a military unit where he was responsible for the classification and selection of army recruits. During this time he developed a semi structured interview technique for personality assessment. After his discharge from military service, he took further courses in the philosophy of science and logic. In 1969 he began an important collaboration with Tversky, which looked at individual heuristics and biases, and demonstrated that people often show pronounced biases in estimating the probability that an event will occur. This emphasis on the internal state of the individual is reflected in the theories that Kahneman put forward, suggesting that attention may be influenced by the amount of effort available, and the level of arousal of the individual.