Microfiche reel · crank through the variations
Endowment Effect
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Reel · endowment-effect
Endowment Effect
People demand substantially more to give up a good they own (willingness-to-accept) than they would pay to acquire the identical good (willingness-to-pay), so mere ownership inflates valuation.
“Using the modified procedures, we observe no gap between WTA and WTP. Therefore, our results call into question the interpretation of observed gaps as evidence of loss aversion or prospect theory.”
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Provenance
Where it was first filed
Richard H. Thaler, 1980 — Toward a Positive Theory of Consumer Choice. Thaler coined the term 'endowment effect' in this 1980 paper, framing it as the underweighting of opportunity costs and grounding it in Kahneman and Tversky's prospect theory: removing a good from one's endowment is coded as a loss, adding it as a gain. The canonical experimental demonstration came a decade later in Kahneman, Knetsch & Thaler (1990, JPE).
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Tested variation 1
KKT 1990 — Cornell mug markets
Median selling price (~$7.12) was more than double median buying price (~$2.87); choosers fell between (~$3.12). Actual-to-predicted trade volume (V/V*) was 0.20 for mugs and 0.41 for pens, versus V/V*=1.0 for induced-value tokens, ruling out transaction costs.
Daniel Kahneman, Jack L. Knetsch, Richard H. Thaler, 1990 · yield WTA/WTP ratio ~2.5; trade volume ratio V/V* = 0.20 (mugs), 0.41 (pens) · Cornell undergraduates across multiple trials (dozens per market)
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Tested variation 2
Knetsch 1989 — exchange asymmetry
About 90% of subjects in each group declined to trade and kept whichever good they were randomly endowed with, evidence of non-reversible indifference curves inconsistent with standard theory.
Jack L. Knetsch, 1989 · yield ~90% retained the endowed good in both arms (well above the ~50% trade rate expected if endowment were irrelevant) · Three groups (choice N=55; mug-endowed N=76; chocolate-endowed N=87)
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Tested variation 3
Plott & Zeiler 2005 — misconceptions control (contesting study)
With the full set of controls, no gap between WTA and WTP was observed, leading the authors to argue that observed gaps may reflect procedural misconceptions rather than loss aversion / prospect-theory preferences.
Charles R. Plott, Kathryn Zeiler, 2005 · yield WTA/WTP gap ~0 (eliminated) under full controls · Lab subjects; mugs and lotteries (C91 lab design)
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Method
How the judgment forms
The classic account is loss aversion under prospect theory (Thaler 1980; Kahneman, Knetsch & Thaler 1990): giving up an owned good is coded as a loss, which looms larger than the equivalent gain of acquiring it, so sellers demand more than buyers will pay. Morewedge & Giblin's (2015) integrative review reframes the dominant explanations as loss-aversion/reference-price, biased information processing, and psychological-ownership accounts, arguing the effect is driven by ownership-induced cognitive framing that biases which attributes are accessible at valuation, rather than by pain of loss per se.
Major rivals: (1) loss aversion / reference dependence; (2) psychological ownership and self-association; (3) a 'bad-deal aversion' or buy–sell strategic-misvaluation account, under which buyers anchor low and sellers anchor high for strategic reasons rather than because ownership changes utility (Weaver & Frederick; Smith; the buy–sell-discrepancy view). A separate methodological camp (Plott & Zeiler) holds that much of the gap is an artifact of subject misconceptions about elicitation procedures. List's field work shows the effect attenuates with trading experience, consistent with a learned/framing rather than fixed-preference mechanism.
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Verdict · replication
contested
The basic WTA>WTP disparity reproduces across many studies — Horowitz & McConnell's (2002) review of ~45 studies found a mean WTA/WTP ratio near 7 overall (and ~2.9 for ordinary private goods) — but its interpretation as a preference-based 'endowment effect' is genuinely disputed. Plott & Zeiler (2005) eliminated the gap with full misconception controls; List (2003) showed it fades with market experience and is absent in experienced traders. The dispute itself has unsettled replications: Isoni, Loomes & Sugden (2011) replicated Plott & Zeiler's no-gap result in the classic mug task but found a residual WTP-WTA gap in Plott & Zeiler's lottery/practice tasks, challenging the lottery-task interpretation rather than the mug result; and Fehr, Hakimov & Kübler (2015) reported a failed replication of Plott & Zeiler's no-gap result. So the phenomenon is robust as a raw valuation gap, but its causal status as ownership-driven loss aversion is contested.
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On record
Documented in the wild
Market experience erodes the endowment effect at sportscard and collector-pin shows · 2003
In a QJE field study, John List ran exchange experiments with real traders at sportscard and Disney pin shows. Inexperienced participants showed the classic reluctance to trade their endowed good, but the effect declined with trading experience and was effectively absent among the most experienced dealers — and individuals who later traded more showed a smaller effect a year on.
Endowment effect in NFL/NBA draft-pick trades · 2022
Hobbs and colleagues analyzed real trades of draft picks across major U.S. professional sports leagues and found patterns consistent with an endowment effect: teams behaved as if they overvalued the picks they already held relative to those they would acquire, distorting trade markets for picks.
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Final frame · the counter-move
Reframe the decision from the neutral chooser's seat: ask 'If I did not already own this, what would I pay for it right now?' and use that number, not your asking price. Because the gap demonstrably shrinks with trading experience (List 2003) and vanishes when valuation procedures are clean (Plott & Zeiler 2005), forcing an explicit buy-equivalent valuation — and getting an outside party to price the asset — neutralizes both the ownership frame and strategic anchoring.
List (2003) found experienced traders show little or no endowment effect; Plott & Zeiler (2005) eliminated the WTA–WTP gap with controlled elicitation, and KKT's own 'chooser' condition priced near buyers, not sellers.
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Adjacent reels
- Loss AversionThe standard mechanistic basis: losses loom larger than equivalent gains, which Thaler invoked to explain why owners overvalue what they would lose.
- Status Quo BiasClosely linked tendency to prefer the current state; endowment effect is often treated as one driver of status-quo stickiness.
- Mere Ownership EffectThe narrower finding that merely owning an object raises liking/valuation even absent a trade decision; one of the ownership-based explanations of the endowment effect.
- Sunk Cost FallacyBoth involve overweighting attachment, but sunk cost is about prior unrecoverable investment, not present ownership of a good.
- WTA–WTP disparityThe measured gap between willingness-to-accept and willingness-to-pay is the operational signature; debate is whether the gap equals an 'endowment effect' of preferences or a procedural artifact.