Attention
Attentional Capture Task
Also called: additional singleton task, additional singleton paradigm, attentional capture paradigm, irrelevant singleton, singleton distractor
Measure how much a shape in an odd color slows the search for a target: participants find a diamond among circles while one circle sometimes has a different color.
5-7 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
- 122
- Evidence grade
- C
- Registered clinical studies
- 1
What it measures
Measures how much a shape in an odd color slows the search for the shape that matters. Six shapes ring the center of the screen; participants find the one diamond among circles and press F or J for the direction of the line inside it. On half the trials one circle has a different color.
Constructs
- Selective attention
- Capture by salient distractors
- Visual search
Research uses
- Attention and distraction research
- Aging and attention research
- Within-study group comparison
How the paradigm works
The attentional capture task measures how much a salient shape that does not matter pulls attention away from the shape that does. It follows the additional singleton paradigm of Theeuwes (1992). Six outlined shapes appear on a ring around a central cross: one diamond, the target, and five circles. Each shape holds a short white line. Participants find the diamond and press F if its line is horizontal or J if it is vertical. The lines in the circles are tilted 22.5 degrees, so they never give the answer. On half the trials one circle has a different color: the odd color stands out more than the diamond's shape, yet it never marks the target.
More about the paradigm
The shapes are red or blue, chosen at random on each trial, and the odd circle has the other color. Changing the colors at random keeps the odd color salient: when the distractor's color stays the same, people learn to ignore it and the cost fades (Adam and colleagues, 2021). Red and blue take the place of Theeuwes's red and green, so the odd color stays plain to people with red-green color blindness. A 600 ms cross comes before each display, and the shapes stay until a response or 2,000 ms. The standard session is 192 trials in a seeded random order, half with the odd color, after 16 practice trials with feedback. The diamond's place, its line and the color are balanced within each condition, and each display is saved with its trial.
The main score is the capture cost: mean correct response time on trials with the odd color minus trials without it. Positive values mean the odd color slowed the search, the capture Theeuwes (1992) reported. The cost is also given as a percent of the mean without the odd color, which allows for overall speed, and from medians. Accuracy in each condition and the difference in accuracy are reported. Responses under 100 ms count as anticipations. A cost measured in response times is noisy for one person, so the score is best used for group comparisons. Scores support research and do not diagnose.
Scores
- Capture Costms
- Mean correct response time on trials with a circle in the odd color minus trials without one.
- Lower means less slowing by the odd color
- Response Time With the Odd Colorms
- Mean correct response time on trials with a circle in the odd color.
- Lower is faster
- Response Time Without the Odd Colorms
- Mean correct response time on trials where every shape had one color.
- Lower is faster
- Capture Cost, Percent%
- The capture cost as a percent of the mean without the odd color.
- Lower means less slowing by the odd color
- Capture Cost, Mediansms
- Median correct response time with the odd color minus without it.
- Lower means less slowing by the odd color
- Accuracy%
- Share of all test trials answered with the key for the line in the diamond.
- Higher is better
- Accuracy With the Odd Color%
- Share of trials with the odd color answered correctly, leaving out responses under 100 ms.
- Higher is better
- Accuracy Without the Odd Color%
- Share of trials without the odd color answered correctly, leaving out responses under 100 ms.
- Higher is better
- Capture Error Effect%
- Accuracy without the odd color minus accuracy with it.
- Positive values mean more errors with the odd color
- Mean Correct Response Timems
- Mean response time of correct answers on all test trials.
- Lower is faster
- Trials Used With the Odd Colortrials
- Correct trials with the odd color at or after 100 ms, the trials the cost uses.
- Fewer than 20 is flagged
- Trials Used Without the Odd Colortrials
- Correct trials without the odd color at or after 100 ms, the trials the cost uses.
- Fewer than 20 is flagged
- Anticipationscount
- Responses under 100 ms from the shapes' onset.
- Lower is better
- Missed Responsescount
- Trials with no key press within 2,000 ms.
- Lower is better
- Total Trialstrials
- Trials in the scored run.
- Informational
Use and evidence
122 papers from 2021 to 2025 name this task in their title or abstract, up 85% compared with 2016 to 2020. That ranks it 169 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 33 |
| 2024 | 25 |
| 2023 | 17 |
| 2022 | 28 |
| 2021 | 19 |
| 2020 | 14 |
| 2019 | 17 |
| 2018 | 14 |
| 2017 | 12 |
| 2016 | 9 |
| 2015 | 7 |
| 2014 | 9 |
| 2013 | 11 |
| 2012 | 9 |
| 2011 | 3 |
| 2010 | 7 |
| 2009 | 2 |
| 2008 | 3 |
| 2007 | 3 |
| 2006 | 3 |
| 2005 | 1 |
| 2004 | 2 |
| 2003 | 0 |
| 2002 | 0 |
| 2001 | 0 |
| 2000 | 0 |
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
- 4
- Papers on reliability or validity
- 12
- Registered clinical studies using it as an outcome
- 1
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
- Six outlined shapes on a ring around a central cross: one diamond and five circles, each with a short white line.
- Lines
- Horizontal or vertical in the diamond, tilted 22.5 degrees in every circle.
- Keys
- F for a horizontal line and J for a vertical one, shown under the shapes on every trial.
- Colors
- All shapes red or all blue, chosen at random on each trial. On distractor trials one circle has the other color.
- Fixation
- 600 ms.
- Shapes
- They stay until a response or 2,000 ms.
- Trial mix
- 192 trials (standard; 96 to 288), half with the odd color, with the diamond's place, its line and the color balanced within each half.
- Order
- A seeded random order, saved with the trial data.
- Practice
- 16 trials with feedback for 800 ms. No feedback in the test.
- Score
- Mean correct response time with the odd color minus without it.
Theeuwes (1992) showed a green circle among green squares, with a red square as the distractor, in separate blocks. This version uses the diamond among circles of Theeuwes (2004), mixes trials with and without the odd color, and uses a red and a blue that switch at random from trial to trial, so the odd color stays salient (Adam and colleagues, 2021) and plain to people with red-green color blindness.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: attentional_capture_test from the scored run, F or J for the line in the diamond (chance 50%) within 2,000 ms, correctness from the recorded key. Below chance invalidates and not above chance is flagged. One key on 90% of answers invalidates when accuracy is not above chance. Missed responses and responses under 100 ms follow the timed-test rule. Fewer than 20 correct trials in either condition 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). Missed responses and responses under 100 ms keep the platform's timed-test rule: more than max(3, 25%) missed responses or more than max(2, 20%) responses under 100 ms invalidate, and any is flagged. A response under 100 ms cannot be a reaction to the stimulus. The capture cost is a difference between two means, so it needs enough correct trials in each condition; the limit of 20 is a ConductScience choice.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Number of trials | 192 | 96 to 288 |
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 Attentional Capture Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Theeuwes, 1992; Theeuwes, 2004), with the standard settings (number of trials: 192). The main score was capture cost (mean correct response time on trials with a circle in the odd color minus trials without one).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Theeuwes, J. (1992). Perceptual selectivity for color and form. Perception & Psychophysics, 51(6), 599-606. https://doi.org/10.3758/BF03211656The additional singleton paradigm: a salient color singleton slows the search for a shape singleton.
- Theeuwes, J. (1991). Cross-dimensional perceptual selectivity. Perception & Psychophysics, 50(2), 184-193. https://doi.org/10.3758/BF03212219
- Theeuwes, J. (2004). Top-down search strategies cannot override attentional capture. Psychonomic Bulletin & Review, 11(1), 65-70. https://doi.org/10.3758/BF03206462The diamond among circles, with the lines in the other shapes tilted 22.5 degrees.
- Bacon, W. F., & Egeth, H. E. (1994). Overriding stimulus-driven attentional capture. Perception & Psychophysics, 55(5), 485-496. https://doi.org/10.3758/BF03205306How the way people search changes the cost.
- Adam, K. C. S., Patel, T., Rangan, N., & Serences, J. T. (2021). Classic visual search effects in an additional singleton task: An open dataset. Journal of Cognition, 4(1), 34. https://doi.org/10.5334/joc.182Colors that switch at random keep the cost; one fixed distractor color lets it fade.
- Luck, S. J., Gaspelin, N., Folk, C. L., Remington, R. W., & Theeuwes, J. (2021). Progress toward resolving the attentional capture debate. Visual Cognition, 29(1), 1-21. https://doi.org/10.1080/13506285.2020.1848949
Source papers
- Theeuwes J (1992). Perceptual selectivity for color and form. Perception & Psychophysics, 51(6):599-606.Paradigm source, Adults
Questions
How long does the Attentional Capture Task take?
About 5 to 7 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?
Capture Cost, Response Time With the Odd Color, Response Time Without the Odd Color, Capture Cost, Percent, Capture Cost, Medians, Accuracy, Accuracy With the Odd Color, Accuracy Without the Odd Color, Capture Error Effect, Mean Correct Response Time, Trials Used With the Odd Color, Trials Used Without the Odd Color, Anticipations, Missed Responses and Total Trials. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Attentional Capture Task used in research?
122 papers from 2021 to 2025 name it in their title or abstract, up 85% compared with 2016 to 2020. That ranks it 169 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 Attentional Capture Task have?
In the published research, 4 papers report its test-retest reliability and 1 registered clinical study uses it as an outcome (evidence grade C in the ConductCognition test census).
Which settings can a researcher change?
Number of trials (96 to 288). 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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