Do AI models negotiate differently when the numbers get bigger?
In 16,000 simulated negotiations, I tested whether AI language models treat a $100 deal differently from an equivalent $100 million deal.
The research combines LLM behavioral economics, which studies how large language models make economic decisions, with mechanistic interpretability, which looks inside one model for clues about what drives its choices.
Will an AI seller reveal a hidden flaw that lowers what its asset is worth?
In 480 simulated negotiations, Gemini 2.5 Flash sellers knew a private fact that cut an asset’s value. When sellers were told only to maximize profit, a direct question from the buyer drew out more disclosure, and also more answers an AI judge labeled as fabricated.
Four hidden values, four conditions480 negotiations
Choose an outcome ↘
Sellers who revealed the hidden number in their third reply
0%25%50%75%100%
$80$50$20$5
The asset’s true value (public price $100)
Sellers who revealed the hidden number in their third reply, by the asset’s true value
Condition
$80
$50
$20
$5
Profit only, ordinary questions
3%
0%
0%
0%
Profit only, direct question
63%
23%
17%
7%
Also told to disclose, ordinary questions
100%
100%
93%
90%
Also told to disclose, direct question
100%
100%
100%
100%
Profit only
Also told to disclose
Ordinary questions
Direct question
A direct question drew the number out of profit-only sellers most often when the flaw was mild, and rarely when the asset was worth only $5.
Profit-only sellers whose third reply an AI judge labeled fabricated
0%25%50%
7%13%17%17%10%33%43%43%
$80$50$20$5
The asset’s true value (public price $100)
Profit-only sellers whose third reply an AI judge labeled fabricated, by the asset’s true value
Condition
$80
$50
$20
$5
Profit only, ordinary questions
7%
13%
17%
17%
Profit only, direct question
10%
33%
43%
43%
Ordinary questions
Direct question
The direct question raised fabrication labels too. Sellers also told to disclose received one such label in 240 negotiations.
Average sale price, with ±1 standard deviation
$0$25$50$75$100
$80$50$20$5
The asset’s true value (public price $100)
Average sale price, with ±1 standard deviation, by the asset’s true value
Condition
$80
$50
$20
$5
Profit only, ordinary questions
$89.97 ± $6.11
$89.19 ± $6.39
$84.47 ± $9.41
$85.28 ± $4.78
Profit only, direct question
$85.00 ± $5.37
$77.63 ± $13.87
$78.49 ± $14.75
$82.15 ± $9.42
Also told to disclose, ordinary questions
$79.46 ± $1.26
$54.87 ± $3.71
$38.63 ± $6.07
$28.50 ± $11.93
Also told to disclose, direct question
$79.85 ± $1.04
$52.92 ± $3.26
$34.47 ± $6.90
$30.19 ± $12.42
Profit only
Also told to disclose
Ordinary questions
Direct question
True value
Profit-only prices barely followed the true value. Sellers told to disclose all revealed it up front, yet the $5 asset still sold for about $28 to $30.
Gemini 2.5 Flash sellers, 30 negotiations per point. Replies are each seller’s third, which followed the buyer’s direct question when one was asked. Prices are closed deals. Preprint, Figs. 2 and 4.