Short answers, pulled from the story.
Thaler won the 2017 Nobel Memorial Prize in Economic Sciences for incorporating psychologically realistic assumptions into analyses of economic decision-making. The Royal Swedish Academy of Sciences credited him with building a bridge between economic and psychological analyses of individual decision-making and with helping create the field of behavioral economics.
The endowment effect, documented by Thaler and colleagues, is the finding that people value objects they own more highly than identical objects they do not own. They tend to demand more money to give up a possession than they would pay to acquire it, contradicting the classical assumption that market value is independent of ownership.
Mental accounting is a concept introduced by Thaler to describe how people categorize money differently depending on its source, treating a tax refund, a bonus, and a regular paycheck as if they have different values even though they are financially equivalent. The concept was formally presented in his 1985 paper in the journal Marketing Science.
Nudge, co-authored with Cass Sunstein and first published by Yale University Press in 2008, argues that the arrangement of choices, called choice architecture, shapes decisions without forcing anyone's hand. The book advocates libertarian paternalism, using default options and reduced friction to steer people toward better outcomes while preserving free choice. A final edition was released in 2021.
Thaler and Sunstein define sludge as any aspect of choice architecture that uses friction to make it harder for people to reach outcomes that would benefit them. Examples they cite include difficult subscription cancellations, mail-in rebates, and opaque pricing, practices that overlap with what designers call dark patterns.
Thaler appeared as himself in The Big Short, a 2015 film about the credit and real estate bubble collapse that led to the 2008 financial crisis. In the film he helped Selena Gomez explain the hot hand fallacy, the tendency to assume that whatever is currently happening will continue to happen. The appearance gave him an Erdos-Bacon number of 5.