Past costs, reference points and noticeable information can influence choices.
A sunk-cost fallacy lets an unrecoverable past cost influence a present choice even though that cost is unchanged by either option. Loss aversion gives losses relative to a reference point greater weight than comparable gains; it is not simply disliking every expense. Salience gives especially noticeable information disproportionate attention. Firms may frame messages or prices around these tendencies. Explain the mechanism without assuming every buyer reacts the same way, and distinguish a useful reminder from misleading information.
- Sunk-cost fallacy
- An unrecoverable past cost distorts the current choice.
- Loss aversion
- A loss relative to a reference point, such as the benefit a person currently has, can weigh more than an equally sized gain.
- Salience
- Noticeable information attracts disproportionate attention.
Apply the distinction
Evidence
A pricing format can appeal to a bias without proving every buyer is affected. Explain the mechanism and check the relevant future comparison.
Worked example: Three ways an offer directs attention
A member has already paid a non-refundable joining fee. A shop urges them to buy an unwanted add-on so the fee will not be wasted. Another offer emphasises losing a current benefit, while a third displays a low headline amount with less noticeable unavoidable charges.
- If the fee cannot be changed by buying the add-on, it is not an additional benefit of that purchase. Using it as the sole reason to buy illustrates sunk-cost fallacy.
- Framing an otherwise equivalent offer as losing something already held may appeal to loss aversion around that reference point.
- Making the headline price stand out while other relevant charges are harder to notice can affect salience and the perceived total price.
- These are possible behavioural mechanisms. Actual effects need evidence, and a current decision should compare relevant future benefits and costs.
Watch out for this
Anything a consumer regrets paying is automatically a sunk-cost fallacy.
The fallacy occurs when an unrecoverable past cost distorts the current choice; recognising a cost or learning from experience is not sufficient.
Check your understanding
A buyer chooses an unwanted extra purchase solely because of a non-refundable fee already paid and unaffected by either choice. Which mechanism is most directly shown?
- An economy of scale.
- A supply shift.
- Sunk-cost fallacy.