We have associations to things. We have, you know, we have associations to tables and to - and to dogs and to cats and to Harvard professors, and that's the way the mind works. It's an association machine.

Many people will admit that they made a mistake [putting money in dot-coms or telecoms at their peak] But that doesn’t mean that they’ve changed their mind about anything in particular. It doesn’t mean that they are now able to avoid that mistake.

So your emotional state really has a lot to do with what you're thinking about and what you're paying attention to.

There's a tendency to look at investments in isolation. Investors focus on the risk of individual securities.

I have always believed that scientific research is another domain where a form of optimism is essential to success: I have yet to meet a successful scientist who lacks the ability to exaggerate the importance of what he or she is doing, and I believe that someone who lacks a delusional sense of significance will wilt in the face of repeated experiences of multiple small failures and rare successes, the fate of most researchers.

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

People just hate the idea of losing. Any loss, even a small one, is just so terrible to contemplate that they compensate by buying insurance, including totally absurd policies like air travel.