“Loss aversion: losses loom larger than gains. The pain of losing $100 exceeds the pleasure of winning $100. This asymmetry—the psychological impact of loss is greater than the impact of corresponding gain—explains much of human economic behavior and decision-making under risk.”
—
Daniel Kahneman
Thinking, Fast and Slow (2011); originally Kahneman & Tversky, Prospect Theory (1979)
Commentary
Loss aversion is not irrationality but an adaptive principle shaped by evolution: losses threaten survival; gains are useful but not critical. This creates asymmetrical weighting that produces systematic violations of expected utility theory.
Practically: people are excessively conservative with investments (fear of loss outweighs hope of gain); they hold losing stocks too long ('hoping to recover'); they resist change (status quo bias—the cost of losing the familiar exceeds the benefit of gaining something new). Recognizing loss aversion can improve decision-making.
Commentary
Loss aversion is not irrationality but an adaptive principle shaped by evolution: losses threaten survival; gains are useful but not critical. This creates asymmetrical weighting that produces systematic violations of expected utility theory.
Practically: people are excessively conservative with investments (fear of loss outweighs hope of gain); they hold losing stocks too long ('hoping to recover'); they resist change (status quo bias—the cost of losing the familiar exceeds the benefit of gaining something new). Recognizing loss aversion can improve decision-making.