Attention
Backward Masking Task
Also called: visual backward masking, visual masking task, pattern masking, target-to-mask interval, stimulus onset asynchrony
Measure early visual processing speed: how long a brief ring must show before a following mask stops people naming the side of its gap.
4-6 minTimed: desktop or laptop with a mouse or trackpad
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- Papers, 2021 to 2025
- 240
- Evidence grade
- C
- Registered clinical studies
- 4
What it measures
A measure of early visual processing speed. A ring with a gap on one side flashes for about 33 ms, and a pattern of lines then covers the same place after one of six fixed intervals, each shown equally often. Participants press the arrow key that points to the gap. The score is the target-to-mask interval at which 75 percent of answers are right.
Constructs
- Early visual processing speed
- Visual masking
- Brief display identification
Research uses
- Schizophrenia and psychosis research
- Visual processing research
- Aging research
How the paradigm works
The Backward Masking Task measures how quickly the visual system takes in a brief display: how long a target must be on its own before a following pattern no longer blocks it. A cross is shown for 600 ms, then a ring with a gap on one side for about 33 ms, then a blank, then a mask for 250 ms: the same ring with no gap, plus short lines at seeded places, over the same spot. The time from the target's onset to the mask's onset comes from a fixed ladder of six intervals, about 33, 50, 67, 100, 150 and 233 ms, and on some trials the target shows alone. Participants then press the arrow key that points to the gap, with no time limit.
More about the paradigm
Every display time is fixed before the session: each interval, and the target alone, appears 10 times (standard; 6 to 16) in a seeded order, with the four gap sides balanced, for 70 trials in about 4 minutes after 6 practice trials with feedback. Nothing a participant answers changes the display times. Displays switch on screen frames through the frame-timed helper, the measured durations are saved on every trial, and trials more than one frame off plan leave the scores. Desktop and laptop only.
The main score is the interval at which 75 percent of answers are right, from a monotone fit to the share right at each interval, interpolated on log interval; lower means faster visual processing. Accuracy at each interval, accuracy with the target alone and the screen's timing are also reported. Scores support research and do not diagnose.
Scores
- Masking Thresholdms
- The time from target onset to mask onset at which 75 percent of answers are right, from a monotone fit to the share right at each interval, interpolated on log interval.
- Lower is better; the target needed less time on its own
- Threshold at Longest Intervalflag
- 1 when even the longest interval stayed under 75 percent right, so the score is the longest interval and only a lower bound.
- 1 is flagged for review
- Threshold at Shortest Intervalflag
- 1 when the shortest interval was already at or above 75 percent right, so the score is the shortest interval and an upper bound.
- 1 is noted for review
- Accuracy by Interval%
- Share right at each target-to-mask interval, keyed by its planned length in whole ms.
- Rises with the interval
- Accuracy with a Mask%
- Share right over all trials with a mask.
- Informational
- Accuracy with the Target Alone%
- Share right when the target showed with no mask.
- Under 50% is invalid and under 80% is flagged for review
- Target Alone Trials Answeredtrials
- Trials with the target alone that were answered and ran on time.
- Informational
- Median Answer Timems
- Median time from the question to the answer.
- Informational; the answer has no time limit
- Early Key Pressescount
- Arrow keys pressed before the question appeared, which are not taken as answers.
- Informational
- Frame Intervalms
- Median time between screen frames during the trials.
- About 16.7 on a 60 Hz screen
- Refresh RateHz
- Screen refresh rate from the frame interval.
- Informational
- Displays on Time%
- Share of answered trials whose target and interval each ran within one frame of plan; only these are scored.
- Under 0.9 is flagged for review
- Completed Trialstrials
- Trials answered in the scored run.
- Fewer than planned is flagged for review
- Planned Trialstrials
- Trials the run set out to show.
- Informational
Use and evidence
240 papers from 2021 to 2025 name this task in their title or abstract, down 32% compared with 2016 to 2020. That ranks it 104 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 59 |
| 2024 | 46 |
| 2023 | 38 |
| 2022 | 64 |
| 2021 | 33 |
| 2020 | 56 |
| 2019 | 73 |
| 2018 | 68 |
| 2017 | 70 |
| 2016 | 85 |
| 2015 | 64 |
| 2014 | 81 |
| 2013 | 93 |
| 2012 | 81 |
| 2011 | 93 |
| 2010 | 131 |
| 2009 | 69 |
| 2008 | 60 |
| 2007 | 62 |
| 2006 | 71 |
| 2005 | 61 |
| 2004 | 71 |
| 2003 | 44 |
| 2002 | 45 |
| 2001 | 48 |
| 2000 | 40 |
Use grade C
100 to 299 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
- 10
- Papers on reliability or validity
- 91
- Registered clinical studies using it as an outcome
- 4
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 31 October 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Display
- On a dark panel: a cross for 600 ms, a ring with a gap on one side for about 33 ms, a blank, then a mask for 250 ms: the same ring with no gap and 12 short lines over the same place.
- Intervals
- Target onset to mask onset of about 33, 50, 67, 100, 150 or 233 ms, set in frames of a 60 Hz screen and shown in whole frames of the screen's own rate. On some trials the target shows alone.
- Answer
- Press the arrow key that points to the gap, with no time limit. Keys pressed before the question are counted and not taken as answers.
- Trials
- 10 at each interval and 10 with the target alone (standard; 6 to 16 each): 70 trials in a seeded order, with the four gap sides balanced within each.
- Practice
- 6 trials, 2 with the target alone and 2 at each of the two longest intervals, with feedback for 1,000 ms.
- Fixed times
- Every display time is set before the session, and no answer changes it: there is no staircase.
- Score
- The interval at which 75 percent of answers are right, from a monotone fit to the share right at each interval, interpolated on log interval. Trials whose displays ran more than one frame off plan leave the score.
Masking studies use letters, shapes or the target's position. This version uses a ring with a gap on one of four sides, so the four answers differ only in where the gap is. The intervals are a fixed ladder (the method of constant stimuli), not a staircase.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: backward_masking_test from the scored run, a choice of four gap sides after the mask, with no time limit (chance 25%). Below chance invalidates and not above chance is flagged; one arrow on 90% of answers invalidates when accuracy is not above chance. Under 50% right with the target alone, on at least four such trials, invalidates and under 80% is flagged. No fitted interval, a fit at the longest interval, a run short of its planned trials, or fewer than 90% of displays within one frame of plan is flagged for review. Answer times are not checked: the answer comes after the mask, when it may already be decided.
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). With the target alone and no mask the gap is plain to see, so errors on those trials mean the target could not be seen or the task was not followed. The display times carry the score, so trials whose displays ran late leave it.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Trials at each interval | 10 | 6 to 16 |
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. 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 Backward Masking Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Breitmeyer and Ogmen, 2006; Green, Nuechterlein and Mintz, 1994), with the standard settings (trials at each interval: 10). The main score was masking threshold (the time from target onset to mask onset at which 75 percent of answers are right, from a monotone fit to the share right at each interval, interpolated on log interval).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Breitmeyer, B. G., & Ogmen, H. (2006). Visual masking: Time slices through conscious and unconscious vision (2nd ed.). Oxford University Press. https://doi.org/10.1093/acprof:oso/9780198530671.001.0001Backward masking and the interval from target onset to mask onset.
- Enns, J. T., & Di Lollo, V. (2000). What's new in visual masking? Trends in Cognitive Sciences, 4(9), 345-352. https://doi.org/10.1016/S1364-6613(00)01520-5
- Green, M. F., Nuechterlein, K. H., & Mintz, J. (1994). Backward masking in schizophrenia and mania: I. Specifying a mechanism. Archives of General Psychiatry, 51(12), 939-944. https://doi.org/10.1001/archpsyc.1994.03950120011003Identifying a brief target at a range of target-to-mask intervals.
- Green, M. F., Lee, J., Wynn, J. K., & Mathis, K. I. (2011). Visual masking in schizophrenia: Overview and theoretical implications. Schizophrenia Bulletin, 37(4), 700-708. https://doi.org/10.1093/schbul/sbr051
- Bach, M. (1996). The Freiburg Visual Acuity Test: Automatic measurement of visual acuity. Optometry and Vision Science, 73(1), 49-53. https://doi.org/10.1097/00006324-199601000-00008A ring with a gap on one of several sides as an on-screen target, answered with one key per side.
Source papers
- Green MF, Nuechterlein KH, Mintz J (1994). Backward masking in schizophrenia and mania. I. Specifying a mechanism. Archives of General Psychiatry, 51(12):939-944.Paradigm source, Adults
Questions
How long does the Backward Masking Task take?
About 4 to 6 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. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Masking Threshold, Threshold at Longest Interval, Threshold at Shortest Interval, Accuracy by Interval, Accuracy with a Mask, Accuracy with the Target Alone, Target Alone Trials Answered, Median Answer Time, Early Key Presses, Frame Interval, Refresh Rate, Displays on Time, Completed Trials and Planned Trials. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Backward Masking Task used in research?
240 papers from 2021 to 2025 name it in their title or abstract, down 32% compared with 2016 to 2020. That ranks it 104 of 395 test families in the ConductCognition test census (use grade C). Source: ConductCognition test census 0.14.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Backward Masking Task have?
In the published research, 10 papers report its test-retest reliability and 4 registered clinical studies use it as an outcome (evidence grade C in the ConductCognition test census).
Which settings can a researcher change?
Trials at each interval (6 to 16). 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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