Loss Aversion
A loss hurts about twice as much as an equivalent gain feels good.
Also known as: Losses loom larger than gains
intermediate Attributed to Daniel Kahneman & Amos Tversky · Prospect theory
Loss aversion is the tendency to feel the pain of a loss more intensely than the pleasure of an equal-sized gain. Because losses loom larger, we take irrational steps to avoid them — holding losing bets, refusing fair gambles, and over-protecting what we already have.
What it is
Kahneman and Tversky's prospect theory put a rough number on it: losing £100 feels about twice as bad as gaining £100 feels good. This asymmetry warps decisions. People reject a coin-flip that pays £150 on heads and loses £100 on tails, even though it's clearly favourable, because the possibility of the loss dominates the larger expected gain.
Loss aversion explains a family of behaviours: clinging to a falling stock to avoid "locking in" the loss, valuing something more once we own it (the endowment effect), and defaulting to the status quo because any change risks a loss. It's also why "don't lose what you have" messaging moves people more than "gain something new."
The feeling is real and often protective — but left unchecked it makes us too timid with favourable risks and too stubborn with failing commitments.
Worked example
An employee is offered a role with higher expected pay but some variability. They turn it down, fixating on the months they might earn less than now, even though on average they'd earn more. The potential losses feel vivid and painful; the larger expected gain feels abstract. Loss aversion, not the maths, made the decision — and it's the same instinct that keeps investors holding losers far too long.
How to counter it
The bias itself is the failure mode: over-weighting losses leads to rejecting good bets and clinging to bad positions. Counter it by evaluating decisions on expected value across many similar choices, and by reframing — asking whether you'd take the bet if you were starting fresh, rather than measuring everything from the pain of a possible loss.
How to apply it
- Judge a repeated decision by its expected value, not the sting of the worst case.
- Reframe "what might I lose?" as "what's the average outcome if I did this often?"
- Watch for holding failing positions just to avoid realising a loss.
- Notice when "protecting what I have" is quietly costing you better options.
Related entries
Sources & further reading
Thinking, Fast and Slow
by Daniel Kahneman · book
Prospect theory and loss aversion are central to Kahneman's account of choice.
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