Hold the time.
After watching how long the screen takes to fill, how accurately can you press and hold for the same length of time, without counting?
Original study
- Vierordt, K. (1868). Der Zeitsinn nach Versuchen. Tübingen: H. Laupp. Source
- Lejeune, H., & Wearden, J. H. (2009). Vierordt's The Experimental Study of the Time Sense (1868) and its legacy. European Journal of Cognitive Psychology, 21(6), 941–960. Source
- Hollingworth, H. L. (1910). The central tendency of judgment. The Journal of Philosophy, Psychology and Scientific Methods, 7(17), 461–469. Source
- Jazayeri, M., & Shadlen, M. N. (2010). Temporal context calibrates interval timing. Nature Neuroscience, 13(8), 1020–1026. Source
- Gibbon, J. (1977). Scalar expectancy theory and Weber's law in animal timing. Psychological Review, 84(3), 279–325. Source
- Grondin, S., Meilleur-Wells, G., & Lachance, R. (1999). When to start explicit counting in a time-intervals discrimination task: A critical point in the timing process of humans. Journal of Experimental Psychology: Human Perception and Performance, 25(4), 993–1004. Source
- Glasauer, S., & Shi, Z. (2021). The origin of Vierordt's law: The experimental protocol matters. PsyCh Journal, 10(5), 732–741. Preprint: Glasauer, S., & Shi, Z. (2018). 150 years of research on Vierordt's law – Fechner's fault? bioRxiv. https://doi.org/10.1101/450726 Source
- Wearden, J. H., & Lejeune, H. (2008). Scalar properties in human timing: Conformity and violations. Quarterly Journal of Experimental Psychology, 61(4), 569–587. Source
Our adaptation
A game adaptation of Vierordt's (1868) duration reproduction task. In each round a full-screen area fills from bottom to top in T seconds (no numbers), then the screen is held down for the same duration; the fill is not visible while holding. Targets are 0.9, 1.6, 2.5, 3.6 and 5.0 seconds, each jittered within ±8%, in random order.
Differences from the original study
- Press and release times include small device-dependent latencies.
- The fill animation depends on the screen refresh rate.
- Counting is not prevented.
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 |
|---|---|---|
t | JSON | Rounds: [[shown target ms, reproduced ms] × 5]. |
pts_1 | number | Round score (0–10): 10 / (1 + (|ln(reproduced / target)| / 0.15)^1.6). (item 1) |
pts_2 | number | Round score (0–10): 10 / (1 + (|ln(reproduced / target)| / 0.15)^1.6). (item 2) |
pts_3 | number | Round score (0–10): 10 / (1 + (|ln(reproduced / target)| / 0.15)^1.6). (item 3) |
pts_4 | number | Round score (0–10): 10 / (1 + (|ln(reproduced / target)| / 0.15)^1.6). (item 4) |
pts_5 | number | Round score (0–10): 10 / (1 + (|ln(reproduced / target)| / 0.15)^1.6). (item 5) |
points | number | Total score (0–50). |
slope | number | Slope of reproduced against target duration (below 1 means short durations were lengthened and long ones shortened). |
indiff | number | Indifference point (ms): the duration where reproduction equals the target; only if the slope is below 0.98 and the result lies between 300 and 9,000 ms. |
short | number | Mean deviation for the two shortest targets (%; positive = longer). |
long | number | Mean deviation for the two longest targets (%). |
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 requires all five rounds with targets between 500 and 8,000 ms and reproductions between 150 and 40,000 ms; it computes scores and summaries itself.
- 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
Leaderboard score: total score (0–50); higher is better.
Leaderboard measure: sense of time (higher is better). The play_score column in the open data is this score for the first play.
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.