Loss Aversion
Loss aversion is the finding that losses weigh approximately 2× heavier than equivalent gains in psychological impact. Losing 100 produces positive feeling.
Primary source: kahneman-2011-thinking-fast-and-slow (developed with amos-tversky in prospect-theory, 1979)
Core Observation
The value function in prospect-theory is steeper for losses than for gains:
- Gains: concave (diminishing marginal utility)
- Losses: convex (diminishing marginal disutility) but the entire loss curve lies below the gain curve
The “2:1 ratio” is an approximation — actual estimates range from 1.5:1 to 2.5:1 depending on the domain and study.
Downstream Effects
| Phenomenon | How loss aversion drives it |
|---|---|
| Endowment effect | Owners demand more to sell than non-owners would pay to acquire — ownership creates a loss-framed reference point |
| Status quo bias | Inaction preferred: changing the status quo feels like accepting a loss |
| Sunk cost fallacy | Prior investments create a reference point; abandoning them feels like locking in a loss |
| Disposition effect | Investors sell winning stocks too early (lock in gains) and hold losing stocks too long (avoid realising losses) |
| Contract framing | ”Avoid losing 100” — exploited in negotiation and marketing |
In Organisations
Loss aversion in management produces excessive risk-aversion for potential gains and irrational risk-seeking to recover from sunk costs. Reference-class thinking and pre-mortems are correctives.
Related Concepts
- prospect-theory — the formal theory containing loss aversion
- cognitive-biases — loss aversion as one of the most consequential biases
- framing-effect — how loss/gain framing shifts choices