The endlessly rising tone.
Can you hear a sound that keeps rising yet never gets any higher? Could the same two notes sound like they go up to you and down to the person next to you?
Original study
- Shepard, R. N. (1964). Circularity in judgments of relative pitch. The Journal of the Acoustical Society of America, 36(12), 2346–2353. Source
- Deutsch, D. (1986). A musical paradox. Music Perception, 3(3), 275–280. Source
- Deutsch, D. (1991). The tritone paradox: An influence of language on music perception. Music Perception, 8(4), 335–347. Source
- Deutsch, D., Henthorn, T., & Dolson, M. (2004). Speech patterns heard early in life influence later perception of the tritone paradox. Music Perception, 21(3), 357–372. Source
- Repp, B. H. (1994). The tritone paradox and the pitch range of the speaking voice: A dubious connection. Music Perception, 12(2), 227–255. Source
- Chambers, C., Akram, S., Adam, V., Pelofi, C., Sahani, M., Shamma, S., & Pressnitzer, D. (2017). Prior context in audition informs binding and shapes simple features. Nature Communications, 8, 15027. Source
- Malek, S., & Sperschneider, K. (2018). Aftereffects of spectrally similar and dissimilar spectral motion adaptors in the tritone paradox. Frontiers in Psychology, 9, 677. Source
- Risset, J.-C. (1969). Pitch control and pitch paradoxes demonstrated with computer-synthesized sounds. The Journal of the Acoustical Society of America, 46(1A), 88. Source
Our adaptation
An adaptation of Shepard (1964) tones and Deutsch's (1986) tritone paradox. All tones consist of octave-spaced sine components under a fixed bell-shaped envelope. Round 1 plays 24 tritone pairs (12 pitch classes × 2 envelope positions) and asks whether the second tone went up or down; in round 2 the tone climbs in semitone steps and at steps 12, 24 and 36 the participant says whether it is still rising and how high it is relative to the start; round 3 compares the first tone of the staircase with the tone at step 36.
Differences from the original study
- Level and speakers are not controlled; phone speakers can distort the envelope, so headphones are recommended.
- Tritone pairs are played before the staircase, because judgments can shift after an ascending sequence (Malek and Sperschneider, 2018).
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 |
|---|---|---|
checkpoints | JSON | Answers at the staircase checkpoints: [[still rising (1 yes, 0 no, 2 unsure), height relative to start (−1 below, 0 same, 1 a bit above, 2 well above, 3 far above)] × 3]. |
same | integer | Which is higher, the first tone or the tone at step 36 (0 the first, 1 step 36, 2 the same). |
tritone | JSON | Tritone pairs: [[pitch class of the first tone 0–11, envelope position, 1 = went up / 0 = went down, time ms] × 24]. |
down | JSON | Share of 'went down' by pitch class (12 values). |
peak | number | Peak of the personal pitch-circle orientation (pitch class, decimal). |
strength | number | Strength of the orientation. |
consistency | number | Share of complementary pairs heard in opposite directions. |
peak_class | integer | Peak pitch class (0–11) if the orientation is clear; otherwise empty. |
rise | integer | Number of checkpoints at which the tone was said to be still rising (0–3). |
height | integer | Height answer at the last checkpoint. |
headphones | integer | Listening mode (1 headphones, 0 speakers). |
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 the three checkpoint answers and the 24 tritone pairs (each pitch class and envelope once), and computes orientation and consistency itself. The clear-orientation threshold is the strength exceeded by only about 5% of fully random answer sets.
- 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 distribution of peak pitch classes and the share hearing the staircase as rising throughout.
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.