We are prone to overestimate how much we understand about the world and to underestimate the role of chance in events.

The concept of loss aversion is certainly the most significant contribution of psychology to behavioral economics.

you know you have made a theoretical advance when you can no longer reconstruct why you failed for so long to see the obvious.

The conclusion is straightforward : self-control requires attention and effort.

Finally, the illusions of validity and skill are supported by a powerful professional culture. We know that people can maintain an unshakeable faith in any proposition, however absurd, when they are sustained by a community of like-minded believers. Given the professional culture of the financial community, it is not surprising that large numbers of individuals in that world believe themselves to be among the chosen few who can do what they believe others cannot.

A large portion of the weekend effects is explained by differences in the amount of time spent with friends or family between weekends and weekdays.

To know whether you can trust a particular intuitive judgment, there are two questions you should ask: Is the environment in which the judgment is made sufficiently regular to enable predictions from the available evidence? The answer is yes for diagnosticians, no for stock pickers. Do the professionals have an adequate opportunity to learn the cues and the regularities? The answer here depends on the professionals' experience and on the quality and speed with which they discover their mistakes.