Processing Speed
Rhythm Discrimination Task
Also called: rhythm discrimination test, same-different rhythm task, beat-based rhythm discrimination, rhythm perception test
Measure rhythm perception as participants hear a rhythm of tones twice, then say whether a third is the same or different, with and without a beat.
9-12 minUntimed
Free to start: 10 free participants per account, then $0.99 per participant for academic research, or any yearly plan. Preview any test free after you sign up.
- Papers, 2021 to 2025
- 53
- Evidence grade
- C
- Registered clinical studies
- 6
What it measures
Measures how well people hear a change in a rhythm. Each round plays a rhythm of tones twice, then a third time that is the same or different, and participants say which. Some rhythms carry a regular beat and some do not. The main score is d-prime, how well changed rhythms are told from unchanged ones.
Constructs
- Rhythm perception
- Beat perception
- Auditory memory for time patterns
- Interval timing
Research uses
- Rhythm and timing research
- Parkinson's disease research
- Music and language research
How the paradigm works
The rhythm discrimination task measures how well people hear a change in a rhythm, and how much a regular beat helps them. Each round plays a rhythm of tones twice and then a third time, and the participant answers whether the third was the same as the first two or different (Grahn and Brett, 2007). Healthy adults discriminate rhythms that carry a beat better than rhythms that do not, and that advantage is much weaker in Parkinson's disease (Grahn and Brett, 2009).
More about the paradigm
The rhythms are built by the task's own code, never taken from a published list. Each has five to seven intervals of one to four units, twelve units in all, then a final tone. Metric simple rhythms place an accent at the start of every four units, which listeners hear as a beat (the accent rules of Povel and Essens, 1985); metric complex rhythms use the same intervals in an order that leaves at least one beat without a tone; nonmetric rhythms keep that order with lengths of 1, 1.4, 3.5 and 4.5 units, which no beat fits. In a different round, two neighboring intervals swap places, so the third rhythm keeps the same intervals and length (Cameron and colleagues, 2016). Each tone fills its interval and stops 40 ms before the next. A unit is 220 to 270 ms and the tones take one of six pitches from 294 to 587 Hz, both drawn for each round, and 1,100 ms of silence separate the three presentations.
At the standard setting a session has 30 rounds: five same and five different rounds of each rhythm type, in runs that hold each kind once, in an order drawn from the session's seed (24 to 48 rounds as a setting). Four practice rounds with feedback come first. Participants press Play to start each round and answer once the third rhythm has ended, with no time limit. Before the test they set a comfortable volume and pass a short headphone check (Woods and colleagues, 2017). The test needs headphones and normal hearing, and it does not test hearing.
The main score is d prime, how well changed rhythms are told from unchanged ones, from the Different answers on changed and on unchanged rhythms, both rates log-linear corrected (Hautus, 1995). d prime is also given for each rhythm type, with the beat advantage (metric simple minus metric complex), percent correct, the hit and false alarm rates and the response criterion. Answers within 100 ms of the buttons turning on are counted as anticipations and left out. Scores support research and do not diagnose.
Scores
- d Primed'
- Sensitivity over all rounds: z of the rate of Different answers on changed rhythms minus z of that rate on unchanged rhythms, both log-linear corrected.
- Higher is better
- Response Criterionz
- Minus half the sum of the two z values behind d prime. Negative values mean a leaning to answer Different.
- Informational
- d Prime, Metric Simpled'
- d prime on rhythms that carry a regular beat.
- Higher is better
- d Prime, Metric Complexd'
- d prime on rhythms with the same intervals in an order without a regular beat.
- Higher is better
- d Prime, Nonmetricd'
- d prime on rhythms whose interval lengths no beat fits.
- Higher is better
- Beat Advantaged'
- d prime on metric simple minus metric complex rhythms, two types with the same intervals.
- Higher means the beat helped more
- Percent Correct%
- Rounds answered correctly, as a percent of the scored rounds (chance is 50%).
- Higher is better
- Percent Correct, Metric Simple%
- Percent correct on metric simple rhythms.
- Higher is better
- Percent Correct, Metric Complex%
- Percent correct on metric complex rhythms.
- Higher is better
- Percent Correct, Nonmetric%
- Percent correct on nonmetric rhythms.
- Higher is better
- Hit Rate%
- Share of changed rhythms answered Different, uncorrected.
- Higher is better
- False Alarm Rate%
- Share of unchanged rhythms answered Different, uncorrected.
- Lower is better
- Median Response Timems
- Median time from the answer buttons turning on to the answer, over the scored rounds.
- Informational
- Anticipationscount
- Answers within 100 ms of the buttons turning on, left out of the scores.
- At least half the rounds makes the session invalid
- Completed Roundscount
- Test rounds answered.
- Informational
- Planned Roundscount
- Test rounds planned by the settings.
- Informational
- Headphone Check Passed0/1
- 1 when the headphone check before the test passed (at least 5 of 6 right), 0 when it did not.
- 0 withholds the percentile
Use and evidence
53 papers from 2021 to 2025 name this task in their title or abstract, up 26% compared with 2016 to 2020. That ranks it 250 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 14 |
| 2024 | 9 |
| 2023 | 9 |
| 2022 | 11 |
| 2021 | 10 |
| 2020 | 1 |
| 2019 | 12 |
| 2018 | 6 |
| 2017 | 11 |
| 2016 | 12 |
| 2015 | 10 |
| 2014 | 4 |
| 2013 | 6 |
| 2012 | 6 |
| 2011 | 6 |
| 2010 | 9 |
| 2009 | 5 |
| 2008 | 7 |
| 2007 | 4 |
| 2006 | 5 |
| 2005 | 9 |
| 2004 | 2 |
| 2003 | 6 |
| 2002 | 4 |
| 2001 | 3 |
| 2000 | 3 |
Use grade D
30 to 99 papers from 2021 to 2025.
Evidence grade C
At least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies.
- Papers on test-retest reliability
- 3
- Papers on reliability or validity
- 15
- Registered clinical studies using it as an outcome
- 6
How the grades work
Use: A is 1,000 or more papers from 2021 to 2025, B 300 to 999, C 100 to 299, D 30 to 99 and E fewer than 30. Evidence: A means at least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome; B, at least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers; C, at least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies; D, little published measurement evidence found. The counts measure use. They include every paper that names the task in its title or abstract. Grades describe the published research on this task, not ConductCognition's version of it.
Source: ConductCognition test census 0.14.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Round
- Play, then a rhythm of tones three times with 1,100 ms of silence between them: twice the same, then the same rhythm or a different one. Same and Different buttons work once the third has ended, with no time limit.
- Rhythms
- Five to seven intervals of one to four units, twelve units in all, then a final tone, built by the task's own code. Metric simple rhythms have a tone on every beat, every four units; metric complex rhythms use the same intervals with at least one beat left silent; nonmetric rhythms use lengths of 1, 1.4, 3.5 and 4.5 units.
- Change
- In a different round two neighboring intervals swap places, so the number of intervals and the length stay the same.
- Tones
- Sine tones that fill each interval and stop 40 ms before the next, with 8 ms ramps. Each round draws a unit of 220 to 270 ms and one of six pitches from 294 to 587 Hz.
- Rounds
- 5 same and 5 different rounds of each rhythm type (standard, 4 to 8 of each), in runs that hold each kind once, in an order drawn from the session's seed: 30 rounds. 4 practice rounds with feedback come first.
- Sound setup
- A comfortable volume set on a steady tone, then a six-round headphone check (Woods and colleagues, 2017). By default a failed check ends the test.
- Score
- d prime from the Different answers on changed and unchanged rhythms, both rates log-linear corrected, overall and for each rhythm type. Answers within 100 ms of the buttons turning on leave the score.
The test needs headphones and normal hearing, and it does not test hearing: the tones play at a volume each participant sets, so the scores compare rhythm perception within a study. The scores support research and do not diagnose.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: rhythm_discrimination_test from the scored run, one Same or Different answer per round once the third rhythm has played, with no time limit (chance 1 in 2; half the rounds of each rhythm type are the same), graded from the saved rhythms. Accuracy significantly below chance invalidates and not above chance is flagged. One answer on 90% of rounds invalidates when accuracy is not above chance. Answers within 100 ms of the buttons turning on, on at least half the rounds, invalidate. A run short of its planned rounds is flagged for review. A failed headphone check that stopped the test invalidates; one the study's setting ran past is flagged and withholds the percentile.
Why these rules
Accuracy significantly below chance (one-sided exact test, p < .05) cannot come from guessing; it means the response mapping was reversed or the task was not followed (Slick, Sherman and Iverson 1999 treat below-chance forced-choice performance as definite response bias). Chance-level accuracy can be a real result in impaired participants, so it is only flagged. One option on at least 90% of answered trials, when the correct options are balanced and accuracy is not above chance, means the answers did not depend on the items (the task counterpart of long-string responding in surveys; Curran 2016). The answer buttons turn on only when the last sound has been heard, and the decision forms while listening, so a quick answer is expected; an answer within 100 ms of the buttons turning on was pressed before they could be seen, and the session is invalid only when at least half the answers are that fast. Woods, Siegel, Traer and McDermott (2017) let only listeners who passed the headphone check go on, because a listener on loudspeakers hears the sounds differently; a session that ran after a failed check keeps its scores but not its percentile.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| When the headphone check fails | Stop the test | Stop the test, Continue the test |
| Same and different rounds per rhythm type | 5 | 4 to 8 |
Yearly plans can change settings within these limits. Free and pay-as-you-go studies use the standard settings.
Need a setting this test does not have?
Devices and languages
- Untimed test: runs on desktops, laptops, tablets and phones. Needs headphones. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Rhythm Discrimination Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Grahn and Brett, 2007; Povel and Essens, 1985), with the standard settings (when the headphone check fails: Stop the test; same and different rounds per rhythm type: 5). The main score was d prime (sensitivity over all rounds: z of the rate of Different answers on changed rhythms minus z of that rate on unchanged rhythms, both log-linear corrected).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Grahn, J. A., & Brett, M. (2007). Rhythm and beat perception in motor areas of the brain. Journal of Cognitive Neuroscience, 19(5), 893-906. https://doi.org/10.1162/jocn.2007.19.5.893
- Grahn, J. A., & Brett, M. (2009). Impairment of beat-based rhythm discrimination in Parkinson's disease. Cortex, 45(1), 54-61. https://doi.org/10.1016/j.cortex.2008.01.005The beat-based advantage and its reduction in Parkinson's disease.
- Povel, D.-J., & Essens, P. (1985). Perception of temporal patterns. Music Perception, 2(4), 411-440. https://doi.org/10.2307/40285311The accent rules that sort the rhythms into types.
- Cameron, D. J., Pickett, K. A., Earhart, G. M., & Grahn, J. A. (2016). The effect of dopaminergic medication on beat-based auditory timing in Parkinson's disease. Frontiers in Neurology, 7, 19. https://doi.org/10.3389/fneur.2016.00019The swap of two intervals that changes a rhythm.
- Woods, K. J. P., Siegel, M. H., Traer, J., & McDermott, J. H. (2017). Headphone screening to facilitate web-based auditory experiments. Attention, Perception, & Psychophysics, 79(7), 2064-2072. https://doi.org/10.3758/s13414-017-1361-2The headphone check before the test.
Source papers
- Grahn and Brett (2007): the three rhythm types and the task. Povel and Essens (1985): the accent model behind the types. Grahn and Brett (2009): the beat-based advantage and its reduction in Parkinson's disease. Cameron, Pickett, Earhart and Grahn (2016): the swap that changes a rhythm.Paradigm source, Adults
Questions
How long does the Rhythm Discrimination Task take?
About 9 to 12 minutes, as listed in the test library.
What device does a participant need?
Untimed test: runs on desktops, laptops, tablets and phones. Needs headphones. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
d Prime, Response Criterion, d Prime, Metric Simple, d Prime, Metric Complex, d Prime, Nonmetric, Beat Advantage, Percent Correct, Percent Correct, Metric Simple, Percent Correct, Metric Complex, Percent Correct, Nonmetric, Hit Rate, False Alarm Rate, Median Response Time, Anticipations, Completed Rounds, Planned Rounds and Headphone Check Passed. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Rhythm Discrimination Task used in research?
53 papers from 2021 to 2025 name it in their title or abstract, up 26% compared with 2016 to 2020. That ranks it 250 of 395 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.14.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Rhythm Discrimination Task have?
In the published research, 3 papers report its test-retest reliability and 6 registered clinical studies use it as an outcome (evidence grade C in the ConductCognition test census).
Which settings can a researcher change?
When the headphone check fails (Stop the test, Continue the test) and same and different rounds per rhythm type (4 to 8). Settings can be changed on yearly plans; free and pay-as-you-go studies use the standard settings.
Which languages can participants use?
Participants can take this test in English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese. English is on every plan, and the other languages come with yearly plans. Have a native speaker read the machine-translated text before launch.
Is this a clinical test?
No. ConductCognition is for research use only. It runs, scores and exports the test; clinical interpretation is outside the platform.
Every test: the full test list.
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