The common pot.
Of your 20 tokens, how many would you put into a common pot that is multiplied by 1.6 and split equally among four people?
Original study
- Ledyard, J. O. (1995). Public goods: A survey of experimental research. In J. H. Kagel & A. E. Roth (Eds.), The handbook of experimental economics (pp. 111–194). Princeton University Press. Source
- Fehr, E., & Gächter, S. (2000). Cooperation and punishment in public goods experiments. American Economic Review, 90(4), 980–994. Source
- Fehr, E., & Gächter, S. (2002). Altruistic punishment in humans. Nature, 415(6868), 137–140. Source
- Fischbacher, U., Gächter, S., & Fehr, E. (2001). Are people conditionally cooperative? Evidence from a public goods experiment. Economics Letters, 71(3), 397–404. Source
- Herrmann, B., Thöni, C., & Gächter, S. (2008). Antisocial punishment across societies. Science, 319(5868), 1362–1367. Source
- Fischbacher, U., & Gächter, S. (2010). Social preferences, beliefs, and the dynamics of free riding in public goods experiments. American Economic Review, 100(1), 541–556. Source
Our adaptation
An adaptation of Fehr and Gächter's (2000) public goods game with punishment, played with recorded group members. The participant and three people drawn from previous participants form a fixed group of four. Each round starts with 20 tokens; every token put into the pot is multiplied by 1.6 and split four ways (individual return 0.4). The first five rounds have no punishment; in the last three, after contributions are shown, spending 1 token removes 3 tokens from a member's earnings (at most 3 punishment points per round).
Differences from the original study
- Tokens are hypothetical; group members are recorded decisions of previous participants and do not react to the participant.
- Rounds without punishment always come first; the effect of punishment cannot be fully separated from learning and fatigue.
- Punishment is capped at 3 points per round.
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 |
|---|---|---|
c_1 | number | Tokens put into the pot in a round (0–20); c_1 … c_8 = rounds 1–8 (6–8 with punishment). (item 1) |
c_2 | number | Tokens put into the pot in a round (0–20); c_1 … c_8 = rounds 1–8 (6–8 with punishment). (item 2) |
c_3 | number | Tokens put into the pot in a round (0–20); c_1 … c_8 = rounds 1–8 (6–8 with punishment). (item 3) |
c_4 | number | Tokens put into the pot in a round (0–20); c_1 … c_8 = rounds 1–8 (6–8 with punishment). (item 4) |
c_5 | number | Tokens put into the pot in a round (0–20); c_1 … c_8 = rounds 1–8 (6–8 with punishment). (item 5) |
c_6 | number | Tokens put into the pot in a round (0–20); c_1 … c_8 = rounds 1–8 (6–8 with punishment). (item 6) |
c_7 | number | Tokens put into the pot in a round (0–20); c_1 … c_8 = rounds 1–8 (6–8 with punishment). (item 7) |
c_8 | number | Tokens put into the pot in a round (0–20); c_1 … c_8 = rounds 1–8 (6–8 with punishment). (item 8) |
mean_c | number | Mean contribution over the eight rounds. |
punish | JSON | Punishment points given to the three group members in rounds 6–8: [[member A, member B, member C] × 3 rounds]. |
others_1 | number | Mean contribution of the other three members in a round (from recorded histories; for conditional cooperation analysis). (item 1) |
others_2 | number | Mean contribution of the other three members in a round (from recorded histories; for conditional cooperation analysis). (item 2) |
others_3 | number | Mean contribution of the other three members in a round (from recorded histories; for conditional cooperation analysis). (item 3) |
others_4 | number | Mean contribution of the other three members in a round (from recorded histories; for conditional cooperation analysis). (item 4) |
others_5 | number | Mean contribution of the other three members in a round (from recorded histories; for conditional cooperation analysis). (item 5) |
others_6 | number | Mean contribution of the other three members in a round (from recorded histories; for conditional cooperation analysis). (item 6) |
others_7 | number | Mean contribution of the other three members in a round (from recorded histories; for conditional cooperation analysis). (item 7) |
others_8 | number | Mean contribution of the other three members in a round (from recorded histories; for conditional cooperation analysis). (item 8) |
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 that the eight contributions are whole numbers from 0 to 20 and that total punishment does not exceed 3 in any punishment round; 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 contribution by round and punishment behavior.
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.