Volunteer's dilemma.
One person's small sacrifice saves everyone: will you be that person in the room?
Original study
- Diekmann, A. (1985). Volunteer's dilemma. Journal of Conflict Resolution, 29(4), 605–610. Source
- Darley, J. M., & Latané, B. (1968). Bystander intervention in emergencies: Diffusion of responsibility. Journal of Personality and Social Psychology, 8(4, Pt. 1), 377–383. Source
- Fischer, P., Krueger, J. I., Greitemeyer, T., Vogrincic, C., Kastenmüller, A., Frey, D., Heene, M., Wicher, M., & Kainbacher, M. (2011). The bystander-effect: A meta-analytic review on bystander intervention in dangerous and non-dangerous emergencies. Psychological Bulletin, 137(4), 517–537. Source
- Goeree, J. K., Holt, C. A., & Smith, A. M. (2017). An experimental examination of the volunteer's dilemma. Games and Economic Behavior, 102, 303–315. Source
- Otsubo, H., & Rapoport, A. (2008). Dynamic volunteer's dilemmas over a finite horizon: An experimental study. Journal of Conflict Resolution, 52(6), 961–984. Source
- Manning, R., Levine, M., & Collins, A. (2007). The Kitty Genovese murder and the social psychology of helping: The parable of the 38 witnesses. American Psychologist, 62(6), 555–562. Source
- Arechar, A. A., Gächter, S., & Molleman, L. (2018). Conducting interactive experiments online. Experimental Economics, 21(1), 99–131. Source
Our adaptation
A simultaneous live-room adaptation of Diekmann's (1985) volunteer's dilemma. When 6 people gather in a public room (3–200 in private rooms), 3 rounds are played; each player starts every round with 100 points and if at least one person presses 'I'll do it' within 20 seconds, volunteers get 75 and everyone else 100; if nobody presses, everyone gets 0. A press is final and is not shown to others until the round ends; the press time is recorded on the server clock.
Differences from the original study
- Points are imaginary.
- Three rounds are played in the same room, so rounds are not independent.
- In streamed rooms, promises made in the chat can change the structure of the game.
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 |
|---|---|---|
group_id | group code | Room code: links rows from the same room; regenerated at random in every release. |
group_size | integer | Number of players in the room. |
points | number | Player's total points. |
rate | number | Share of rounds in which the player volunteered. |
none | number | Share of the room's rounds with no volunteer. |
first_s | number | Second of the room's first press (median over rounds). |
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
Answers to this experiment are never accepted from the browser; they are written on the server from the room's action records only when the room ends.
- 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 volunteering rate and the no-volunteer rate by group size.
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.