The trust game.
How much of 100 TL (Turkish lira) would you hand over to a stranger, knowing it will be tripled?
Original study
- Berg, J., Dickhaut, J., & McCabe, K. (1995). Trust, reciprocity, and social history. Games and Economic Behavior, 10(1), 122–142. Source
- Ortmann, A., Fitzgerald, J., & Boeing, C. (2000). Trust, reciprocity, and social history: A re-examination. Experimental Economics, 3(1), 81–100. Source
- Johnson, N. D., & Mislin, A. A. (2011). Trust games: A meta-analysis. Journal of Economic Psychology, 32(5), 865–889. Source
- Cox, J. C. (2004). How to identify trust and reciprocity. Games and Economic Behavior, 46(2), 260–281. Source
- Bohnet, I., Greig, F., Herrmann, B., & Zeckhauser, R. (2008). Betrayal aversion: Evidence from Brazil, China, Oman, Switzerland, Turkey, and the United States. American Economic Review, 98(1), 294–310. Source
- Glaeser, E. L., Laibson, D. I., Scheinkman, J. A., & Soutter, C. L. (2000). Measuring trust. Quarterly Journal of Economics, 115(3), 811–846. Source
- Kovacs, R., Dunaiski, M., Galizzi, M. M., Grimalda, G., Hortala-Vallve, R., Murtin, F., & Putterman, L. (2024). The determinants of trust: Findings from large, representative samples in six OECD countries. Economica, 91(364), 1521–1552. Source
Our adaptation
A hypothetical two-role adaptation of the trust game of Berg, Dickhaut and McCabe (1995). Across five rounds the roles alternate in a fixed order: investor, trustee, investor, trustee, investor. The investor sends 0–100 TL out of 100 TL in 10 TL steps; the amount sent is tripled and the amount returned is set by the return ratio of a random previous participant who faced the same amount as trustee. The trustee receives three times the amount a previous investor sent and decides how much to return.
Differences from the original study
- Money is hypothetical; the counterpart is a recorded decision, not a live person.
- Every participant plays both roles.
- The trustee has no endowment of their own.
Measured variables
The columns of the open data file. List fields are expanded into numbered columns (for example rt_60, est_3); JSON columns contain only numbers and fixed stimulus names.
| Column | Type | Description |
|---|---|---|
sent_1 | number | Amount sent in the investor rounds (TL; sent_1 … sent_3 = rounds 1, 3 and 5). (item 1) |
sent_2 | number | Amount sent in the investor rounds (TL; sent_1 … sent_3 = rounds 1, 3 and 5). (item 2) |
sent_3 | number | Amount sent in the investor rounds (TL; sent_1 … sent_3 = rounds 1, 3 and 5). (item 3) |
trustee | JSON | Trustee rounds: [{"recv": TL received, "ret": TL returned, "r": return ratio}] (2 rounds). |
back_1 | number | Amount returned to the participant in the investor rounds (TL; from a recorded trustee's ratio). (item 1) |
back_2 | number | Amount returned to the participant in the investor rounds (TL; from a recorded trustee's ratio). (item 2) |
back_3 | number | Amount returned to the participant in the investor rounds (TL; from a recorded trustee's ratio). (item 3) |
Columns present in every file (14)
row_id | string | Row code. Regenerated at random in every release; it does not identify a person and cannot be matched across releases or experiments. |
experiment | string | Short name of the experiment (URL slug). |
experiment_version | integer | Version of the answer format. For experiments whose format changed, only the current format is published. |
date | YYYY-MM-DD | YYYY-Www | YYYY-MM | Day the answer was given (Istanbul time). If fewer than 5 answers share the same day, language and device, it is coarsened to the ISO week, and to the month if that is still too few. |
date_precision | day | week | month | Precision of the date column. |
lang | tr | en | (boş) | Interface language. Language recording started in the first week of October 2026; for earlier answers it is known only in experiments whose stimuli depend on the language, and empty otherwise. |
device | desktop | mobile | tablet | (boş) | Device class reported by the browser (class only; browser details are neither stored here nor published). |
source | site | embed | Where the answer came from: the balabs site or the experiment embedded on another site. The embedding site is not published. |
mode | free | daily | challenge | race | session | (boş) | Play mode in scored experiments: free play, daily round, challenge, race room, experiment session. Empty for unscored experiments and for older answers that did not store it. |
color_vision | normal | rg | by | contrast | (boş) | In color-based experiments, the color vision mode the participant chose: normal, red-green, blue-yellow or high contrast. Stimuli are generated along different axes per mode, so compare within a mode. Empty for other experiments. |
first_play | 1 | Every row is a participant’s first play of this experiment (always 1). Replays are stored only as leaderboard scores and are not part of the open data. |
seen_before | yes | no | unsure | (boş) | Participant’s own report of whether they had seen this experiment or its known answer before (in experiments that ask). |
duration_s | number | Time from the start of the experiment to submitting the answer, in seconds (measured in the browser, 0.1 s). |
play_score | number | Leaderboard score of the first play (scored experiments; defined on the method card). Empty for unscored experiments. |
Exclusion criteria
The server checks the three amounts sent as multiples of 10 between 0 and 100, and the trustee decisions between 0 and 300 with the amount returned not exceeding the amount received; invalid submissions are rejected.
- Only each participant's first answer to this experiment; replays are not included.
- Simulated rows, bots, banned and sample accounts are not included.
- Answers before 3 October 2026 are not included (the first day the open data notice was live).
Scoring
This experiment has no leaderboard score. The crowd result is the mean share sent (trust) and the return ratio (trustworthiness).
Version notes
- October 2026
The interface language (lang) started being stored with each answer; for earlier answers it is known only in experiments whose stimuli depend on the language, and empty otherwise.