Social Cognition
Ultimatum Game
Measure responses to unfair offers: participants accept or reject splits of 10 points from programmed partners, scored by how often unfair offers are accepted.
3-6 minUntimed
Free to start: 10 free participants per account, then $0.99 per participant for academic research, or any yearly plan. Preview any test free after you sign up.
- Papers, 2021 to 2025
- 592
- Evidence grade
- C
- Registered clinical studies
- 10
What it measures
Measures responses to unfair offers: the participant accepts or rejects splits of 10 points offered by programmed partners, where a rejection leaves both with nothing.
Constructs
- Fairness
- Social preferences
- Costly punishment
- Social decision making
Research uses
- Behavioral economics research
- Fairness and social norm studies
- Social decision-making research in clinical groups
- Within-study group comparison
How the paradigm works
The Ultimatum Game measures how people respond to unfair offers. In each round a partner has 10 points and offers the participant part of them. If the participant accepts, both get the split; if the participant rejects, neither gets anything, so turning down an unfair offer costs points. Partners are computer programs that follow set rules, and by default the instructions say so.
More about the paradigm
The task follows Güth, Schmittberger and Schwarze (1982) in the responder role, with fair and unfair offers as in Sanfey and colleagues (2003). Offers run from 1 to 5 of the 10 points. Each appears 4 times as standard, each from a new partner, in blocks of the five splits shuffled from the session's seed, for 20 offers. The outcome shows after each choice, and a comprehension question with feedback comes first. Researchers can set 2 to 5 offers per split, add a proposer block in which the participant makes 5 offers to programmed responders, use a neutral partner wording, and choose the payment line.
Scores
- Unfair Offer Acceptance%
- Share of offers of 3 points or fewer (of 10) accepted.
- Higher means more unfair offers accepted
- Acceptance Rate%
- Share of all offers accepted.
- Informational
- Acceptance at 1 Point%
- Share of 1-point offers (a 9:1 split) accepted. Rates are also reported for offers of 2, 3, 4 and 5 points.
- Informational
- Lowest Consistently Accepted Offerpoints
- The lowest offer from which every offer as high or higher was accepted. Empty when an equal split was rejected.
- Lower means more offers accepted
- Comprehension Check%
- Share of the comprehension questions answered correctly.
- 1 supports interpretation
- Mean Offer Share%
- In the optional proposer block, the amount offered as a proportion of the 10 points, averaged over rounds.
- Higher means more generous offers
Use and evidence
592 papers from 2021 to 2025 name this task in their title or abstract, about the same as from 2016 to 2020. That ranks it 39 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 164 |
| 2024 | 119 |
| 2023 | 94 |
| 2022 | 97 |
| 2021 | 118 |
| 2020 | 78 |
| 2019 | 126 |
| 2018 | 130 |
| 2017 | 141 |
| 2016 | 118 |
| 2015 | 136 |
| 2014 | 135 |
| 2013 | 127 |
| 2012 | 126 |
| 2011 | 103 |
| 2010 | 83 |
| 2009 | 79 |
| 2008 | 85 |
| 2007 | 58 |
| 2006 | 35 |
| 2005 | 36 |
| 2004 | 43 |
| 2003 | 31 |
| 2002 | 19 |
| 2001 | 27 |
| 2000 | 24 |
Use grade B
300 to 999 papers from 2021 to 2025.
Evidence grade C
At least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies.
- Papers on test-retest reliability
- 3
- Papers on reliability or validity
- 61
- Registered clinical studies using it as an outcome
- 10
How the grades work
Use: A is 1,000 or more papers from 2021 to 2025, B 300 to 999, C 100 to 299, D 30 to 99 and E fewer than 30. Evidence: A means at least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome; B, at least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers; C, at least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies; D, little published measurement evidence found. The counts measure use. They include every paper that names the task in its title or abstract. Grades describe the published research on this task, not ConductCognition's version of it.
Source: ConductCognition test census 0.14.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Partners
- Computer programs that follow set rules, a new one for each offer, named by letter. The standard instructions say so; a neutral wording says only "your partner".
- Offers
- 1 to 5 of the 10 points (splits 9:1 to 5:5), each 4 times (standard; 2 to 5), so 20 offers, in blocks of the five splits shuffled from the session's seed.
- Choice
- Accept: both get the split. Reject: neither gets anything. Two buttons, in an order drawn from the seed for the whole session.
- Outcome
- Shows for 1,500 ms after each choice.
- Unfair offers
- 3 points or fewer (splits 7:3, 8:2 and 9:1).
- Check
- One question with feedback before the offers: what a rejection pays, for an example offer drawn from the seed.
- Proposer block
- Off by default. When on, 5 offers to programmed responders that accept any offer at or above a minimum of 1, 2, 3, 4 or 5 points, one each; their answers show at the end.
- Money
- Points are hypothetical by default; a setting changes the instruction line to say the study pays.
Güth and colleagues paired participants who bargained over real money. Here partners are programmed, the participant answers offers at set splits from 1 to 5 of 10 points, and the points are hypothetical unless the study pays.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: the scored run's choices on offers, and its proposals when the proposer block is on. No choice is correct, so accuracy is not judged against chance, and accepting or rejecting every offer is accepted. A wrong comprehension answer, or rejecting every equal split, is flagged for review. Choices under 200 ms on at least half the decisions invalidate.
Why these rules
There is no correct option to compare with chance, so accuracy is not judged against chance. Accepting every offer, or rejecting every unfair one, is a stable preference, so repeated choices are not checked. A participant who misreads what a rejection does may choose the opposite of what they intend, so a wrong comprehension answer is flagged for review and never invalidates; so is rejecting every equal split, which may mean the rule was misread. An answer under 200 ms is faster than a simple visual reaction, so it cannot reflect the item. Following response-time effort screening for untimed tests (Wise and Kong 2005), the session is invalid only when at least half the answers are that fast.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Offers per split | 4 | 2 to 5 |
| Proposer block | Off | On or off |
| Partner wording | A computer program (standard) | A computer program (standard), Neutral: your partner |
| Payment line | Hypothetical points (standard) | Hypothetical points (standard), The study pays for points |
Yearly plans can change settings within these limits. Free and pay-as-you-go studies use the standard settings.
Need a setting this test does not have?
Devices and languages
- Untimed test: runs on desktops, laptops, tablets and phones. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- No percentile. Scores and quality flags only. How norms work
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Ultimatum Game in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Güth W, Schmittberger R, Schwarze B, 1982; Sanfey AG, Rilling JK, Aronson JA, Nystrom LE, Cohen JD, 2003), with the standard settings (offers per split: 4; proposer block: Off; partner wording: A computer program; payment line: Hypothetical points). The main score was unfair offer acceptance (share of offers of 3 points or fewer (of 10) accepted).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Güth, W., Schmittberger, R., & Schwarze, B. (1982). An experimental analysis of ultimatum bargaining. Journal of Economic Behavior & Organization, 3(4), 367-388. https://doi.org/10.1016/0167-2681(82)90011-7
- Sanfey, A. G., Rilling, J. K., Aronson, J. A., Nystrom, L. E., & Cohen, J. D. (2003). The neural basis of economic decision-making in the Ultimatum Game. Science, 300(5626), 1755-1758. https://doi.org/10.1126/science.1082976Fair and unfair offers to the responder.
- Oosterbeek, H., Sloof, R., & van de Kuilen, G. (2004). Cultural differences in ultimatum game experiments: Evidence from a meta-analysis. Experimental Economics, 7(2), 171-188. https://doi.org/10.1023/B:EXEC.0000026978.14316.74Typical offers and rejection rates.
Source papers
- Güth, Schmittberger and Schwarze (1982): the ultimatum game. Oosterbeek, Sloof and van de Kuilen (2004): meta-analysis of 37 papers with 75 results.Paradigm source, Adults
Questions
How long does the Ultimatum Game take?
About 3 to 6 minutes, as listed in the test library.
What device does a participant need?
Untimed test: runs on desktops, laptops, tablets and phones. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Unfair Offer Acceptance, Acceptance Rate, Acceptance at 1 Point, Lowest Consistently Accepted Offer, Comprehension Check and Mean Offer Share. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Ultimatum Game used in research?
592 papers from 2021 to 2025 name it in their title or abstract, about the same as from 2016 to 2020. That ranks it 39 of 395 test families in the ConductCognition test census (use grade B). Source: ConductCognition test census 0.14.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Ultimatum Game have?
In the published research, 3 papers report its test-retest reliability and 10 registered clinical studies use it as an outcome (evidence grade C in the ConductCognition test census).
Does it report a percentile?
No. Scores and quality flags only.
Which settings can a researcher change?
Offers per split (2 to 5), proposer block (On or off), partner wording (A computer program (standard), Neutral: your partner) and payment line (Hypothetical points (standard), The study pays for points). Settings can be changed on yearly plans; free and pay-as-you-go studies use the standard settings.
Which languages can participants use?
Participants can take this test in English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese. English is on every plan, and the other languages come with yearly plans. Have a native speaker read the machine-translated text before launch.
Is this a clinical test?
No. ConductCognition is for research use only. It runs, scores and exports the test; clinical interpretation is outside the platform.
Every test: the full test list.
Run this test in your next study
Start free with 10 free participants on any test, then use participant credits or a yearly plan.
Related tests