Demonstration 1 of 4
The loss-adjusted selling price
How large a gap between selling and buying prices does loss aversion create?
Without loss aversion the owner and the buyer share one threshold, the use value. Loss aversion lifts only the owner's threshold, opening a band of prices at which neither trades.
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Dana owns the mug and Eli does not; both value using it at $6. Giving up the mug is coded as a loss weighted by the loss coefficient lambda, so Dana's minimum selling price WTA is lambda times $6. Eli's maximum buying price WTP stays at $6.
Predict first. With lambda = 1, does Dana sell at the posted price of $7.50?
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Constructed example: the chapter's hypothetical mug (use value $6, lambda 1.5 and 1, posted price $7.50); lambda 2 and 2.5 and posted prices $5 and $10 are added for comparison.
Calculated values
- WTA (Dana, owner)
- $9.00
- WTP (Eli, buyer)
- $6.00
- Wedge WTA - WTP
- $3.00
- Dana at the posted price
- Keeps the mug
- Eli at the posted price
- Declines
In dollars, WTA = 1.5 x 6 = 9.00 and WTP = $6.00, a wedge of $9.00 - $6.00 = $3.00. At the posted price, $7.50 is below her $9.00 threshold, so Dana keeps the mug; $7.50 is above his $6.00 use value, so Eli declines.
Worked steps
- WTA = 1.5 x $6 = $9.00
- WTP = use value = $6.00
- Wedge = $9.00 - $6.00 = $3.00
- Dana: $7.50 < $9.00, so she keeps the mug
- Eli: $7.50 > $6.00, so he declines
Use the idea
When owners hold out for much more than buyers will pay, check whether the gap is a loss-weighted threshold rather than a difference in use value.
Where the conclusion applies
A riskless exchange with negligible wealth effects and transaction costs, a single loss coefficient and equal use values. Ownership alone does not prove loss aversion.
Check your understanding: With lambda = 2, what is the wedge?
Chapter 16 source: section "Loss aversion".
Demonstration 2 of 4
Regret beats a better gamble
Can anticipated regret make a chooser reject a gamble with a higher expected value?
Squaring the payoff difference makes the large $50 regret in the bad state outweigh many small rejoicings in the good state. The expected payoffs never change; the comparison with the rejected option does.
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S is the sure payment and G pays $65 with probability p, otherwise $0. Both outcomes are revealed. d is the gamble's payoff minus the sure payoff in each state, and Q(d) = d squared for d at or above 0 and minus d squared for d below 0. D(G,S) is the probability-weighted sum of Q.
Predict first. At p = 0.95 with the sure $50, does the chooser still take the sure payment?
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Constructed example: the chapter's hypothetical choice (sure $50 against $65 with probability 0.9); sure payments $40 and $45 and probabilities 0.95 and 0.99 are added for comparison.
Calculated values
- E[S]
- $50.00
- E[G]
- $58.50
- Q(good)
- 225
- Q(bad)
- -2,500
- D(G,S)
- -47.50
- Choice
- Sure payment
E[G] = 0.90 x 65 = $58.50, above the sure $50.00. With both outcomes revealed, the good state gives d = 65 - 50 = 15 and Q = 225; the bad state gives d = 0 - 50 = -50 and Q = -2,500. D(G,S) = 0.90 x 225 + 0.10 x (-2,500) = 202.50 + (-250.00) = -47.50, negative, so the chooser takes the sure payment despite the gamble's higher expected value.
Worked steps
- E[G] = 0.90 x 65 + 0.10 x 0 = $58.50
- Good state: d = 65 - 50 = 15, Q = 15 x 15 = 225
- Bad state: d = 0 - 50 = -50, Q = -(50 x 50) = -2,500
- D(G,S) = 0.90 x 225 + 0.10 x (-2,500) = 202.50 + (-250.00) = -47.50
- D(G,S) < 0, so the chooser takes the sure payment
Use the idea
When people turn down a favorable gamble whose result they will see next to the safe option, ask whether hiding the foregone result would change the choice.
Where the conclusion applies
Linear outcome utility, a single illustrative odd comparison rule Q and full revelation of both outcomes. A different Q or no feedback can reverse the choice.
Check your understanding: With S = 40 and p = 0.9, what is D(G,S)?
Chapter 16 source: section "Regret theory".
Demonstration 3 of 4
When history sneaks into the decision
Can a larger, irrecoverable past spend flip a forward-looking decision?
Only the forward value matters for the decision, and it is the same in every state. The sunk-cost term adds history to the score, and a large enough past spend pushes it above zero.
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B is expected receipts from finishing the documentary and C the remaining cost. Past spending is sunk and conveys no information. The committee's score adds alpha times the disclosed past spending.
Predict first. With alpha = 0.05 and $200,000 sunk, does the committee continue?
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Constructed example: the chapter's hypothetical documentary (receipts $45,000, cost $60,000, alpha 0.10, sunk $20,000 or $200,000); sunk $100,000 and weights 0, 0.05 and 0.20 are added for comparison.
Calculated values
- Forward value B - C
- -$15,000
- Sunk-cost term
- $20,000
- Continuation score
- $5,000
- Committee decision
- Continue
- Rational decision
- Stop
B - C = $45,000 - $60,000 = -$15,000 whatever was spent before. The committee adds 0.10 x 200,000 = 20,000 dollars, so its score is -15,000 + 20,000 = 5,000 and it continues, taking on an expected loss of $15,000.
Worked steps
- B - C = 45,000 - 60,000 = -15,000
- Sunk-cost term = 0.10 x 200,000 = 20,000
- Score = -15,000 + 20,000 = 5,000
- Score > 0, so the committee continues
Use the idea
Before continuing a project, write down the remaining cost and remaining benefit alone; if the decision changes once past spending is mentioned, the past spending is doing the work.
Where the conclusion applies
No resale value, past spending that carries no information about receipts, and a linear sunk-cost weight alpha.
Check your understanding: What past spending makes the alpha = 0.10 committee indifferent?
Chapter 16 source: section "Sunk-cost effect".
Demonstration 4 of 4
Six bets as one portfolio
How does looking at a bundle of favorable bets change the chance of losing money?
Seen one at a time, each bet has a 50 percent chance of a loss. Pooled, gains in some bets offset losses in others, so six bets lose with probability 34.375 percent. The fall is not smooth: because payoffs come in whole heads, 12 bets at $120 lose slightly more often (38.721 percent), while at $150 the chance drops to 19.385 percent. The expected total grows with every bet.
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Each bet pays the heads payoff or loses $100 on a fair coin. h is the number of heads among n independent bets. The loss probability is the chance the bundle's total is below zero.
Predict first. With 12 bets instead of 6, does the loss probability rise or fall?
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Constructed example: the chapter's hypothetical six bets (+$120 or -$100 on a fair coin); bundles of 1 and 12 bets and heads payoffs of $110 and $150 are added for comparison.
Calculated values
- Expected value per bet
- $10.00
- Expected bundle total
- $60.00
- Loss probability
- 34.375%
- Worst case
- -$600
- Losing outcomes
- 2 or fewer heads
Each bet is worth 0.5 x 120 - 0.5 x 100 = 10.00 dollars, so 6 bets are worth 6 x 10.00 = 60.00. With h heads the total is 120h - 100(6 - h) = 220h - 600, which is negative when h is 2 or fewer. That happens in 22 of 2^6 = 64 equally likely sequences, a loss probability of 34.375%; the worst case is -$600.
Worked steps
- Per bet: 0.5 x 120 - 0.5 x 100 = 10.00
- Bundle: 6 x 10.00 = 60.00
- Total with h heads: 220h - 600
- Loss when h <= 2 (at least 4 tails)
- P(loss) = 22 / 64 = 34.375%
Use the idea
Judge a repeated favorable risk by the distribution of the total, not by the chance of losing on any single round.
Where the conclusion applies
Independent fair coins, identical bets and enough liquidity to bear the worst case.
Check your understanding: With one bet paying $120 after heads, what is the loss probability?
Chapter 16 source: section "Narrow bracketing".