Attention
Ventriloquism Task
Also called: ventriloquist effect, ventriloquism effect, ventriloquist illusion, visual bias of auditory localization, audiovisual spatial localization
Measure how far a flash of light pulls the place a sound seems to come from: participants click where short sounds came from while a light flashes beside them.
7-9 minTimed: desktop or laptop with a mouse or trackpad
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
- 73
- Evidence grade
- D
- Registered clinical studies
- 0
What it measures
A measure of how much a light pulls the place a sound seems to come from. A short burst of noise plays from the left, ahead or the right, placed by the time difference between the ears, often with a small light flashing at the same moment to one side of it, and participants click on a line where the sound came from. The score is the visual pull: how far the answers move with the light, as a percent of the light's move.
Constructs
- Audiovisual integration
- Spatial hearing
- Multisensory perception
- Visual capture of sound location
Research uses
- Multisensory integration research
- Spatial perception research
- Aging and development studies
- Within-study group comparison
How the paradigm works
The ventriloquism task measures how much a light pulls the place a sound seems to come from, the effect a ventriloquist uses to make a voice seem to come from a puppet's mouth. A short burst of noise plays in the headphones from the left, ahead or the right, often with a small light flashing at the same moment to one side of it, and participants click on a line where the sound came from, ignoring the light. Bertelson and Aschersleben (1998) showed that a light flashed in step with a sound draws its heard place toward the light even when people cannot tell they differ, and that the pull is lost when the light and the sound are out of step. Alais and Burr (2004) showed that the pull follows how precisely each sense locates the event, which is why it is a common measure of audiovisual integration.
More about the paradigm
The sound is placed by the time difference between the ears, as in Alais and Burr (2004): the left ear 500 microseconds ahead, no difference, or the right ear ahead. Each sound comes alone or with the light 40 line units to its left or to its right, on a line from -100 at the left end to +100 at the right end. The light shows for three frames of a 60 Hz screen (about 50 ms) and the noise lasts 50 ms, timed so the sound is heard as the light appears. The standard session has 8 trials of each of the 9 pairs of sound and light, 72 in all, after 6 practice sounds alone with feedback on their side, in about 8 minutes with the sound setup.
The test needs headphones and normal hearing. Before it, a loudness step sets a comfortable volume and the headphone check of Woods and colleagues (2017) checks that headphones are worn; a failed check stops the test unless the study chooses to continue. The browser reports how late its sound output plays, and the sound is scheduled to allow for it; most wireless headphones add a delay it cannot see, so wired headphones are best.
Scores
- Visual Pull%
- At each sound, the mean answer with the light to the right less the mean answer with the light to the left, as a percent of the distance between the lights, averaged over the sounds.
- Higher means a stronger pull
- Visual Pull, Sound Ahead%
- The visual pull for the sound with no time difference between the ears.
- Higher means a stronger pull
- Visual Pull, Sounds to the Side%
- The visual pull for the left and right sounds together.
- Higher means a stronger pull
- Shift Toward a Left Light%
- Mean shift of the answers toward a light on the left against the same sound alone, as a percent of the light's offset.
- Informational
- Shift Toward a Right Light%
- Mean shift of the answers toward a light on the right against the same sound alone, as a percent of the light's offset.
- Informational
- Sound Alone Spanscore
- Mean answer to the right sound alone less that to the left sound alone, in line units from -100 to +100.
- Under 20 is flagged for review
- Sound Alone Side%
- Share of answers to the left and right sounds alone on the sound's side of the middle.
- Higher is better
- Sound Alone Spreadscore
- Mean spread of the answers to each sound alone, in line units.
- Lower is more consistent
- Median Answer Timems
- Median time from the question to the answer.
- Informational
- Displays on Time%
- Share of answered trials whose light showed for its planned frames with none dropped.
- Below 0.9 is flagged for review
- Sound to Light Offsetms
- Median time from the light reaching the screen to the sound being heard, by the browser's clocks; 0 is planned.
- Near 0 is on time
- Reported Output Delayms
- Delay of the sound output that the browser reported, null when it reported none.
- Informational
- Headphone Check Passed0/1
- 1 when the headphone check passed.
- 0 is flagged
Use and evidence
73 papers from 2021 to 2025 name this task in their title or abstract, up 28% compared with 2016 to 2020. That ranks it 219 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 15 |
| 2024 | 11 |
| 2023 | 19 |
| 2022 | 17 |
| 2021 | 11 |
| 2020 | 14 |
| 2019 | 16 |
| 2018 | 10 |
| 2017 | 11 |
| 2016 | 6 |
| 2015 | 9 |
| 2014 | 10 |
| 2013 | 19 |
| 2012 | 14 |
| 2011 | 14 |
| 2010 | 16 |
| 2009 | 12 |
| 2008 | 8 |
| 2007 | 8 |
| 2006 | 3 |
| 2005 | 3 |
| 2004 | 10 |
| 2003 | 8 |
| 2002 | 5 |
| 2001 | 8 |
| 2000 | 5 |
Use grade D
30 to 99 papers from 2021 to 2025.
Evidence grade D
Little published measurement evidence found.
- Papers on test-retest reliability
- 0
- Papers on reliability or validity
- 26
- Registered clinical studies using it as an outcome
- 0
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.
- Display
- A gray cross on black above a line 800 pixels long, its places from -100 at the left end to +100 at the right end.
- Sounds
- A 50 ms burst of noise at the level set in the loudness step, placed by the time difference between the ears: the left ear 500 microseconds ahead, no difference, or the right ear 500 microseconds ahead.
- Light
- None, or a white disk 20 pixels wide, 40 line units to the left or right of the sound's place (10 units for each 100 microseconds), for 3 frames of a 60 Hz screen (about 50 ms). The sound is heard as the light appears.
- Fixation
- 600 to 1,000 ms, drawn at random for each trial.
- Answer
- A click on the line where the sound came from, or a mark moved with the arrow keys and set with Enter, with no time limit.
- Length
- 8 trials of each of the 9 pairs of sound and light (6 to 12), in rounds of 9 in a random order: 72 trials.
- Practice
- 6 sounds alone, each place twice, with feedback on the side the sound came from.
- Sound setup
- A loudness step, then the headphone check of Woods and colleagues (2017). A failed check stops the test unless the study chooses to continue.
- Scoring
- The visual pull: at each sound, the mean answer with the light to the right less that with the light to the left, as a percent of the 80 units between the lights, averaged over the sounds.
- Timing
- Trials whose light did not show for its planned frames are left out. The time from the light to the sound, by the browser's clocks, is saved with every answer.
The test needs headphones and normal hearing. The studies cited played sounds from loudspeakers or placed them in a laboratory; this version places them by the time difference between the ears, which is heard inside the head, so places on the line are relative and the pull compares answers to the same sound. The browser reports how late its sound output plays and the sound is scheduled to allow for it, but most wireless headphones add a delay the browser cannot see, so wired headphones are best. Sizes are not calibrated to the viewing distance. No percentile: the pull is a bias, not a better or worse score. 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: ventriloquism_test from the scored run, a place on a line answered with no time limit. Only the left and right sounds with no light have a right answer, the side of the middle they came from (chance 50%); every other answer is the measure and is not judged. Below chance on those sides invalidates and not above chance is flagged; one side of the line on 90% of answers invalidates when the sides are not above chance; answers under 200 ms on at least half the trials invalidate. A headphone check that stopped the test invalidates, and one that failed while the test ran on is flagged. Sounds alone placed the wrong way round or under 20 line units apart, no visual pull, a run short of its planned trials, or fewer than 90% of trials with their light on time is flagged for review.
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). An answer under 200 ms is faster than a simple visual reaction, so it cannot reflect the item. Following response-time effort screening for untimed tests (Wise and Kong 2005), the session is invalid only when at least half the answers are that fast. A sound led by one ear is heard on that side over headphones, so answers to the sounds alone show whether the task was followed and whether the headphones were on the right ears. The pull is the shift of the answers between lights on either side of the same sound, which means little when left and right sounds were not told apart.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Trials per sound and light | 8 | 6 to 12 |
| When the headphone check fails | Stop the test | Stop the test, Continue the test |
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
- Timed test: participants need a desktop or laptop with a mouse or trackpad. Needs headphones. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- No percentile. Scores and quality flags only. How norms work
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Ventriloquism Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Bertelson P, Aschersleben G, 1998; Alais D, Burr D, 2004), with the standard settings (trials per sound and light: 8; when the headphone check fails: Stop the test). The main score was visual pull (at each sound, the mean answer with the light to the right less the mean answer with the light to the left, as a percent of the distance between the lights, averaged over the sounds).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Bertelson, P., & Aschersleben, G. (1998). Automatic visual bias of perceived auditory location. Psychonomic Bulletin & Review, 5(3), 482-489. https://doi.org/10.3758/BF03208826A light flashed with a sound draws its heard place, and does not when out of step with it.
- Alais, D., & Burr, D. (2004). The ventriloquist effect results from near-optimal bimodal integration. Current Biology, 14(3), 257-262. https://doi.org/10.1016/j.cub.2004.01.029The pull follows how precisely each sense places the event.
- Burr, D., & Alais, D. (2006). Combining visual and auditory information. Progress in Brain Research, 155, 243-258. https://doi.org/10.1016/S0079-6123(06)55014-9Sounds placed only by the time difference between the ears.
- 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.
Source papers
- Bertelson P, Aschersleben G (1998). Automatic visual bias of perceived auditory location. Psychonomic Bulletin & Review, 5(3):482-489.N 22, Adults (mean age 28)
- Alais D, Burr D (2004). The ventriloquist effect results from near-optimal bimodal integration. Current Biology, 14(3):257-262.N 6, Adults
Questions
How long does the Ventriloquism Task take?
About 7 to 9 minutes, as listed in the test library.
What device does a participant need?
Timed test: participants need a desktop or laptop with a mouse or trackpad. Needs headphones. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Visual Pull, Visual Pull, Sound Ahead, Visual Pull, Sounds to the Side, Shift Toward a Left Light, Shift Toward a Right Light, Sound Alone Span, Sound Alone Side, Sound Alone Spread, Median Answer Time, Displays on Time, Sound to Light Offset, Reported Output Delay and Headphone Check Passed. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Ventriloquism Task used in research?
73 papers from 2021 to 2025 name it in their title or abstract, up 28% compared with 2016 to 2020. That ranks it 219 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 Ventriloquism Task have?
In the published research, 0 papers report its test-retest reliability and 0 registered clinical studies use it as an outcome (evidence grade D in the ConductCognition test census).
Does it report a percentile?
No. Scores and quality flags only.
Which settings can a researcher change?
Trials per sound and light (6 to 12) and when the headphone check fails (Stop the test, Continue the test). 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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