Avoiding decisions or choosing safe options to escape the painful emotion of later regretting a 'wrong' choice.
Imagine you have two doors. Behind one is a prize, behind the other is nothing. You're so scared of picking the wrong door and feeling bad about it that you don't pick any door at all — even though not picking guarantees you get nothing. That fear of feeling 'I should have picked the other one' is regret aversion.
Regret aversion describes the pattern in which people anticipate the painful self-blame they would feel if a decision turned out poorly, and then let that anticipated emotion override a rational cost-benefit analysis of their options. This can manifest in two opposing ways: as decision paralysis (refusing to act because any action might be regretted) or as impulsive action (rushing to seize an opportunity to avoid the regret of missing out). The bias affects both errors of commission — dreading the consequences of an active choice gone wrong — and errors of omission — dreading the consequences of failing to act when one should have. Because people tend to overestimate the intensity and duration of future regret, the bias systematically distorts choices toward overly conservative, status-quo-preserving behavior, even when bolder action would be statistically superior.
The same glitch looks different depending on the terrain. Finance, medicine, a relationship, a team — same mechanism, different costume.
Investors hold losing positions too long and sell winning positions too early because they dread the emotional pain of locking in a loss or missing further gains. This also drives excessive cash holdings and reluctance to rebalance portfolios after downturns, causing systematic underperformance relative to passive benchmarks.
Patients may decline recommended preventive screenings or surgeries because they fear regretting a complication from the procedure more than they fear the disease itself. Physicians may over-order diagnostic tests not for clinical value but to preemptively avoid the regret of a missed diagnosis.
Formalized independently in 1982 by Graham Loomes and Robert Sugden, David E. Bell, and Peter C. Fishburn. Loomes and Sugden's paper 'Regret Theory: An Alternative Theory of Rational Choice Under Uncertainty' in The Economic Journal (1982) is the most widely cited foundational work.
In ancestral environments with high stakes and limited information, avoiding actions whose outcomes could not be undone (such as entering dangerous territory or consuming unfamiliar food) was often safer than bold exploration. The capacity to mentally simulate regret before committing to an irreversible action served as an emotional brake, preventing reckless risk-taking in environments where a single mistake could be fatal.
Recommendation systems trained on user engagement data can learn to present only safe, familiar options because users who click on novel recommendations and dislike them generate strong negative feedback signals (analogous to regret), while the opportunity cost of never surfacing novel content is invisible in the training data. This creates a conservative loop where the algorithm mirrors human regret aversion, suppressing exploration and serendipity.
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