Loss Aversion

"losses loom larger than corresponding gains"

"In prospect theory, loss aversion refers to the tendency for people to strongly prefer avoiding losses than acquiring gains. Some studies suggest that losses are as much as twice as psychologically powerful as gains. Loss aversion was first convincingly demonstrated by Amos Tversky and Daniel Kahneman."

"The principle of loss aversion was first introduced by Kahneman and Tversky (1979)"

Tversky and Kahneman (1991) "The central assumption of the theory is that losses and disadvantages have greater impact on preferences than gains and advantages."

"Numerous studies have shown that people feel losses more deeply than gains of the same value (Kahneman and Tversky 1979, Tversky and Kahneman 1991)."
Goldberg and von Nitzsch (1999) pages 97-98

"Both the status quo bias and the endowment effect are part of a more general issue known as loss aversion." (Montier 2007, p. 32)

Loss aversion - Wikipedia