Attention
Inattentional Blindness Task
Also called: IB task, sustained inattentional blindness task, dynamic inattentional blindness task, unexpected object task, inattentional blindness paradigm
Measure whether participants notice an unexpected cross while they count the bounces of moving shapes, read across a group, with divided- and full-attention trials.
4-6 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
- 181
- Evidence grade
- C
- Registered clinical studies
- 2
What it measures
Measures whether people notice an unexpected object while their attention is busy. Participants count how often white or black shapes touch the edges of a box; on one trial a cross moves across the middle, and questions then ask whether they saw anything else. The main score is whether the cross was noticed, a measure read across a group. The surprise works once, so each person takes this test once.
Constructs
- Inattentional blindness
- Selective attention
- Attentional set
- Awareness
Research uses
- Attention research
- Awareness and consciousness research
How the paradigm works
Inattentional blindness is the failure to notice an unexpected object while attention is on something else (Mack and Rock, 1998; Simons and Chabris, 1999). This is the sustained version of Most and colleagues (2001), as Wood and Simons (2019) ran it in the browser. Four white and four black shapes move about a blue box for 15 seconds, and the participant counts how often the shapes of one color touch the edges. After a practice trial with feedback and one more counted trial, a cross moves across the middle of the box on the third trial, in view for 5 seconds. Questions then ask whether the participant saw anything other than the shapes, and the cross's shape and color, guessing if nothing was seen. A divided-attention trial (counting again, the cross again) and a full-attention trial (watching only) follow with the same questions (Kreitz et al., 2015), then one question on doing such a task before.
More about the paradigm
The main score is whether the cross was noticed on the critical trial: a yes with its shape or color right, as Wood and Simons (2019) code it. Each person gives one critical answer, so the noticing rate is read across a group, as in the sources. The answers after the divided- and full-attention trials and the error of the counts are reported too, and the shape and color answers stay in the data, since people who say no can still pick the right features more often than chance as a group (Nartker et al., 2025). Noticing depends on how much the cross looks like the counted and the ignored shapes (Most et al., 2001); its color is a setting. Scores support research and do not diagnose.
Scores
- Noticed the Cross0/1
- 1 when the participant said they saw something on the critical trial and named the cross's shape or color, 0 when not.
- Read across a group: the mean is the noticing rate
- Said They Saw Something0/1
- 1 when the participant answered yes after the critical trial.
- Informational
- Shape Right0/1
- 1 when the cross was chosen from six shapes after the critical trial, guessed or not.
- Chance is 1 in 6
- Color Right0/1
- 1 when the cross's color was chosen from six colors after the critical trial, guessed or not.
- Chance is 1 in 6
- Noticed on the Divided-Attention Trial0/1
- The same coding after the fourth trial, counted while the cross could be expected.
- Read across a group
- Noticed on the Full-Attention Trial0/1
- The same coding after the last trial, watched without counting.
- 0 is flagged for review
- Count Error%
- Mean error of the counts on the three counted test trials, as a percent of the true count.
- Lower means the counting was followed
- Count Error on the Critical Trial%
- Error of the count on the critical trial, as a percent of the true count.
- Informational
- Counts Off by Halfcount
- Counted test trials with no count or a count off by more than half.
- 2 or more makes the session invalid
- Did a Task Like This Before0/1
- 1 when the participant said they had done this task or one like it before, 0 when not; empty for not sure.
- 1 is flagged for review
- Earlier Sessionscount
- This participant's sessions of this test begun before this one.
- More than 0 is flagged: only a first session measures inattentional blindness
- Anticipationscount
- Answers given under 100 ms after the question appeared, left out of the scores.
- More than max(2, 20%) of the answers makes the session invalid
- Dropped Frame Rate%
- Share of frames the browser dropped while the shapes moved.
- Above 0.05 is flagged for review
Use and evidence
181 papers from 2021 to 2025 name this task in their title or abstract, up 8% compared with 2016 to 2020. That ranks it 131 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 56 |
| 2024 | 39 |
| 2023 | 29 |
| 2022 | 21 |
| 2021 | 36 |
| 2020 | 35 |
| 2019 | 27 |
| 2018 | 35 |
| 2017 | 37 |
| 2016 | 34 |
| 2015 | 29 |
| 2014 | 35 |
| 2013 | 22 |
| 2012 | 28 |
| 2011 | 34 |
| 2010 | 44 |
| 2009 | 19 |
| 2008 | 12 |
| 2007 | 18 |
| 2006 | 22 |
| 2005 | 19 |
| 2004 | 8 |
| 2003 | 4 |
| 2002 | 1 |
| 2001 | 9 |
| 2000 | 7 |
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
- 1
- Papers on reliability or validity
- 31
- Registered clinical studies using it as an outcome
- 2
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
- Four white and four black shapes (a square, a circle, a triangle and a diamond, 32 to 45 px) in a light blue box of 560 by 480 px with an 8 px square in the middle. All stay still for 1,000 ms, then move for 15,000 ms.
- Motion
- Each shape moves on a diagonal at 52.8, 105.6 or 158.4 px per second, steps to the next speed after 300 to 1,000 ms at random, and bounces off the edges at the same speed. The counted color passes in front.
- Task
- Count how often the shapes of one color touch the edges and type the count. The color is white or black, set for each session from its seed (standard), or chosen in the settings.
- Unexpected cross
- On the third trial a cross 32 px across, gray as standard (white, black or red as a setting), moves along the middle line at 96 px per second, in view for 5,000 ms from 8,000 ms into the motion. It comes and goes behind invisible edges 56 px in from each side.
- Questions
- After the third, fourth and fifth trials: was anything there other than the shapes, then the shape (6 drawn shapes) and the color (6 colors), guessing if nothing was seen. Last, one question on doing such a task before.
- Trials
- A practice trial with the true count as feedback, a counted trial, the critical trial, a divided-attention trial (counting, the cross again) and a full-attention trial (watching only).
- Score
- Noticed: a yes with the cross's shape or color right. One answer per person, so the noticing rate is read across a group. The count errors and the divided- and full-attention answers are reported too.
- Once per person
- The cross is a surprise only the first time, so each person takes the test once. Scoring flags a later session of the same participant and a reported earlier task like this one.
The last screen explains the cross and asks people not to tell others; studies debrief participants as their ethics review requires. The test runs on a desktop or laptop, and sizes and speeds are in screen pixels. Results are read across a group and do not diagnose; no percentile is computed.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: inattentional_blindness_count and inattentional_blindness_question from the scored run, practice left out. Accuracy is not judged against chance, since each person gives one critical answer. Two or more of the 3 counts missing or off by more than half invalidate. A cross missed on the full-attention trial, a reported earlier task like this one, an earlier session of this test and more than 5% of motion frames dropped are flagged for review. Responses under 100 ms follow the timed-test rule.
Why these rules
The cross is unexpected only once, so a person gives one critical answer and chance cannot be judged from it. Counting the bounces is what holds attention, so a session whose counts were missing or off by more than half did not test noticing under load (Wood and Simons 2019 leave such sessions out). A cross missed when watching was the only task, or an earlier encounter with the task, makes a miss or a sighting hard to read, so those sessions are flagged rather than dropped (Kreitz et al. 2015; Nartker et al. 2025). The motion is the display, so dropped frames change what was shown.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Color of the unexpected cross | Gray (standard) | Gray (standard), White, Black, Red |
| Shapes to count | White or black, set for each session (standard) | White or black, set for each session (standard), White, Black |
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 Inattentional Blindness Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Most et al., 2001), with the standard settings (color of the unexpected cross: Gray; shapes to count: White or black, set for each session). The main score was noticed the cross (1 when the participant said they saw something on the critical trial and named the cross's shape or color, 0 when not).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Most, S. B., Simons, D. J., Scholl, B. J., Jimenez, R., Clifford, E., & Chabris, C. F. (2001). How not to be seen: The contribution of similarity and selective ignoring to sustained inattentional blindness. Psychological Science, 12(1), 9-17. https://doi.org/10.1111/1467-9280.00303The task: counting bounces while an unexpected cross moves across, and the cross's likeness to the counted shapes.
- Wood, K., & Simons, D. J. (2019). Now or never: Noticing occurs early in sustained inattentional blindness. Royal Society Open Science, 6(11), 191333. https://doi.org/10.1098/rsos.191333The browser version: the shapes, their speeds, 5 seconds of the cross in view and the coding of noticing.
- Kreitz, C., Furley, P., Memmert, D., & Simons, D. J. (2015). Inattentional blindness and individual differences in cognitive abilities. PLoS ONE, 10(8), e0134675. https://doi.org/10.1371/journal.pone.0134675Divided- and full-attention trials after the critical trial.
- Most, S. B., Scholl, B. J., Clifford, E. R., & Simons, D. J. (2005). What you see is what you set: Sustained inattentional blindness and the capture of awareness. Psychological Review, 112(1), 217-242. https://doi.org/10.1037/0033-295X.112.1.217
- Simons, D. J., & Chabris, C. F. (1999). Gorillas in our midst: Sustained inattentional blindness for dynamic events. Perception, 28(9), 1059-1074. https://doi.org/10.1068/p281059
- Nartker, M., Firestone, C., Egeth, H., & Phillips, I. (2025). Sensitivity to visual features in inattentional blindness. eLife, 13, RP100337. https://doi.org/10.7554/eLife.100337People who report no cross can still pick its features more often than chance, as a group.
Source papers
- Most et al. (2001): the task. Wood and Simons (2019): the browser version, its sizes and speeds, and the coding of noticing. Kreitz et al. (2015): the divided- and full-attention trials.Paradigm source, Adults
Questions
How long does the Inattentional Blindness 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?
Noticed the Cross, Said They Saw Something, Shape Right, Color Right, Noticed on the Divided-Attention Trial, Noticed on the Full-Attention Trial, Count Error, Count Error on the Critical Trial, Counts Off by Half, Did a Task Like This Before, Earlier Sessions, Anticipations and Dropped Frame Rate. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Inattentional Blindness Task used in research?
181 papers from 2021 to 2025 name it in their title or abstract, up 8% compared with 2016 to 2020. That ranks it 131 of 395 test families in the ConductCognition test census (use grade C). Source: ConductCognition test census 0.14.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Inattentional Blindness Task have?
In the published research, 1 paper reports its test-retest reliability and 2 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?
Color of the unexpected cross (Gray (standard), White, Black, Red) and shapes to count (White or black, set for each session (standard), White, Black). 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.
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