Attention
Brief Letter Report Task
Also called: TVA whole report, theory of visual attention, whole-report paradigm, visual processing speed
Measure visual processing speed and short-term storage capacity from letters flashed at several durations, followed by masks.
7-10 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. Try it here first, with no account.
- Papers, 2021 to 2025
- 50
- Evidence grade
- C
- Registered clinical studies
- 3
What it measures
Measure visual processing speed and short-term storage capacity. Six letters flash at several fixed durations, followed by masks. Participants report the letters they saw. A whole-report model separates processing speed, capacity and the exposure threshold.
Constructs
- Visual processing speed
- Visual short-term capacity
- Perceptual threshold
Research uses
- Visual attention research
- Aging research
- Clinical group comparisons
How the paradigm works
Brief letter report measures how visual information builds up with exposure time. Six original consonants appear together around fixation, then masks cover them. Reports at seven durations from about 17 to 300 ms reveal both the rise in performance and its capacity limit.
More about the paradigm
The standard session has six practice reports and 84 scored reports, twelve at each duration. Participants type only letters they are fairly sure they saw, in any order, without a deadline. All durations are set before the session. Measured screen-frame times, stimuli, masks and reports are saved.
Our scorer fits an equal-rate exponential encoding model with a capacity limit by maximum likelihood. Each of six letters has rate C/6 after threshold t0. A fractional capacity K mixes the two neighboring integer limits. Processing speed C is the primary measure, with K, t0, raw report counts, precision and fit diagnostics alongside it. Timing faults are excluded from fitting; insufficient or flat data yield no model estimate. This restricted whole-report fit does not estimate spatial bias, distractor selection or sensory persistence.
Scores
- Visual Processing Speedletters/s
- Fitted total encoding rate C across six letters.
- Higher means faster encoding under this model.
- Short-term Capacityitems
- Fitted capacity K, with neighboring integer capacities mixed.
- Estimated number of letters held at once.
- Exposure Thresholdms
- Fitted t0 before encoding begins.
- Read with screen timing and model fit.
- Mean Letters Reporteditems
- Mean correctly reported identities across all durations.
- Descriptive; depends on the exposure mix.
- Letters at 17 msitems
- Mean correctly reported letters at the planned 17 ms exposure (rounded).
- Compare the curve across durations.
- Letters at 33 msitems
- Mean correctly reported letters at the planned 33 ms exposure (rounded).
- Compare the curve across durations.
- Letters at 50 msitems
- Mean correctly reported letters at the planned 50 ms exposure (rounded).
- Compare the curve across durations.
- Letters at 83 msitems
- Mean correctly reported letters at the planned 83 ms exposure (rounded).
- Compare the curve across durations.
- Letters at 133 msitems
- Mean correctly reported letters at the planned 133 ms exposure (rounded).
- Compare the curve across durations.
- Letters at 200 msitems
- Mean correctly reported letters at the planned 200 ms exposure (rounded).
- Compare the curve across durations.
- Letters at 300 msitems
- Mean correctly reported letters at the planned 300 ms exposure (rounded).
- Compare the curve across durations.
- Model Fit Erroritems
- Root mean squared error of duration-specific means, weighted by trial count.
- Above 0.75 letters is flagged for review.
- Model Negative Log Likelihoodscore
- Negative log likelihood of the correct-letter counts.
- Compare models fitted to the same data only.
- Model at Parameter Limit0/1
- One when C, K or t0 reaches a fitting bound.
- A boundary fit is flagged.
- Reports Used in Fitcount
- Reports with measured display timing within one frame of plan.
- Faulty displays remain in raw report scores.
- Report Precision%
- Correct letters divided by all letters submitted.
- Low precision indicates many reported letters were absent.
- Median Report Timems
- Time from the report prompt to submission, excluding submissions under 100 ms.
- Descriptive; speed is not the goal.
- Anticipationscount
- Premature keys and submissions under 100 ms.
- Premature keys are not accepted.
- Frame Intervalms
- Median measured frame interval.
- Describes the screen timing.
- Displays on Time%
- Share with measured exposure and mask within one frame of plan and no display interruption.
- Below 90% is flagged for review.
- Planned Reportscount
- Number of scored reports planned.
- Compare with completed reports.
- Completed Reportscount
- Number of valid report rows in the selected run.
- Blank reports count; missing rows do not.
Use and evidence
50 papers from 2021 to 2025 name this task in their title or abstract, down 55% compared with 2016 to 2020. That ranks it 361 of 582 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 11 |
| 2024 | 9 |
| 2023 | 8 |
| 2022 | 7 |
| 2021 | 15 |
| 2020 | 18 |
| 2019 | 27 |
| 2018 | 14 |
| 2017 | 30 |
| 2016 | 21 |
| 2015 | 25 |
| 2014 | 24 |
| 2013 | 19 |
| 2012 | 19 |
| 2011 | 16 |
| 2010 | 20 |
| 2009 | 12 |
| 2008 | 21 |
| 2007 | 4 |
| 2006 | 6 |
| 2005 | 8 |
| 2004 | 1 |
| 2003 | 3 |
| 2002 | 4 |
| 2001 | 2 |
| 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
- 22
- Registered clinical studies using it as an outcome
- 3
Measured on ConductCognition
Pooled across the studies that feed our platform norms, by device group. A figure needs 50 or more people.
No pooled figure yet.
Note on the counts: includes theory papers.
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 0.39.0, counted 8 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Display
- Six distinct consonants, drawn from a 20-letter alphabet, around the center of a 300 by 220 px dark panel. Letters are 30 px; their centers lie on an ellipse with horizontal radius 90 px and vertical radius 76 px.
- Timing
- A central dot for 500 ms, letters for about 17, 33, 50, 83, 133, 200 or 300 ms, then crossing-stroke masks at all six positions for 500 ms. Display times are fixed before the session. Actual exposure, mask duration and frame interval are recorded.
- Answer
- Type the letters you are fairly sure you saw, in any order, then press Enter or choose Done. There is no deadline. Blank reports are allowed; repeated letters are not accepted. Backspace corrects the last letter.
- Length
- 12 trials at each of seven durations, 84 total, in seeded order. The setting allows 8 to 24 trials per duration, 56 to 168 total. A short break follows every 28 scored trials.
- Practice
- Six reports at 300, 300, 200, 200, 83 and 83 ms, each followed by the letters and a correct-letter count for 1,000 ms.
- Model
- Maximum-likelihood fit of an equal-rate exponential encoding model with a capacity limit: C letters per second, K stored letters and t0 milliseconds before encoding starts. Fractional K mixes its neighboring integer capacities. The fit uses measured exposures from displays within one frame of plan.
- Scores
- Processing speed, capacity and threshold, mean letters at each duration, report precision, fit error and parameter-limit flags. A fit needs at least 35 reports over five measured durations spanning at least 100 ms, with increasing report counts.
This is an original, equal-weight implementation of the whole-report model described in the TVA literature. It estimates neither spatial bias nor target selection. Screen timing, Latin-letter familiarity and report precision affect the estimates. Review flagged fits alongside raw reports; published clinical cutoffs and norms are not applied.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scores use the completed run's letter reports. A blank report means no letters were seen. Low recall is part of the measure, so accuracy and repeated answers do not invalidate a run. Reports submitted under 200 ms on at least half the trials invalidate. Premature keys are counted and ignored. Missing reports, fewer than 90% of displays within one frame of plan, or report precision below 80% are flagged for review. Display interruptions are recorded.
Why these rules
Report accuracy depends on brief exposure and memory. A person may correctly report no letters at short exposures; this is not an omission. Display timing is needed to interpret letter report performance.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Reports at each duration | 12 | 8 to 24 |
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.
- 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 Brief Letter Report Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Bundesen, 1990; Kyllingsbæk, 2006), with the standard settings (reports at each duration: 12). The main score was visual processing speed (fitted total encoding rate C across six letters).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Bundesen, C. (1990). A theory of visual attention. Psychological Review, 97(4), 523-547. https://doi.org/10.1037/0033-295X.97.4.523
- Kyllingsbæk, S. (2006). Modeling visual attention. Behavior Research Methods, 38(1), 123-133. https://doi.org/10.3758/BF03192757Whole-report likelihood and exponential encoding with a capacity limit. This task uses its own fitting code and a restricted capacity distribution.
Source papers
Questions
How long does the Brief Letter Report Task take?
About 7 to 10 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?
Visual Processing Speed, Short-term Capacity, Exposure Threshold, Mean Letters Reported, Letters at 17 ms, Letters at 33 ms, Letters at 50 ms, Letters at 83 ms, Letters at 133 ms, Letters at 200 ms, Letters at 300 ms, Model Fit Error, Model Negative Log Likelihood, Model at Parameter Limit, Reports Used in Fit, Report Precision, Median Report Time, Anticipations, Frame Interval, Displays on Time, Planned Reports and Completed Reports. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Brief Letter Report Task used in research?
50 papers from 2021 to 2025 name it in their title or abstract, down 55% compared with 2016 to 2020. That ranks it 361 of 582 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.39.0, counted 8 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Brief Letter Report Task have?
In the published research, 3 papers report its test-retest reliability and 3 registered clinical studies use it as an outcome (evidence grade C in the ConductCognition test census).
Does it report a percentile?
No. Scores and quality flags only.
Which settings can a researcher change?
Reports at each duration (8 to 24). 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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