Attention
Object-Based Attention Task
Also called: two-rectangle paradigm, two-rectangles task, Egly paradigm, same-object advantage task, object-based cueing task
Measure how much faster attention moves within an object than to another object: after a cue at one end of a rectangle, participants press for a square at the far end or on the other rectangle.
9-11 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
- 49
- Evidence grade
- D
- Registered clinical studies
- 0
What it measures
Measures how much faster attention moves within an object than to another object the same distance away. Two rectangles stand around a cross, one end brightens, and a white square then fills that end, the far end of the same rectangle or the near end of the other rectangle. Participants press the space bar as soon as they see it.
Constructs
- Object-based attention
- Spatial attention
- Perceptual grouping
Research uses
- Visual attention research
- Perceptual organization research
- Within-study group comparison
How the paradigm works
The Object-Based Attention Task measures whether attention moves more easily within an object than from one object to another. Egly, Driver and Rafal (1994) showed people two outlined rectangles and cued one end with a brief brightening. A target at the far end of the cued rectangle was detected faster than a target the same distance away on the other rectangle, so attention had followed the object as well as the space. Their display became the most used test of object-based attention (Chen, 2012).
More about the paradigm
Two rectangles stand around a central cross, side by side on half the trials and one above the other on the rest. They appear 1,000 ms before the cue. One end brightens for 100 ms, and 200 ms later a white square fills an end. On 75% of the trials with a target it fills the cued end, on 12.5% the far end of the cued rectangle (same object) and on 12.5% the near end of the other rectangle (different object). The last two are the same distance from the cue. Participants press the space bar as soon as they see the square. One trial in nine has no square and needs no press.
The primary score is the same-object benefit: mean detection time on different-object trials minus same-object trials. The benefit is small: 13 ms in the first report, 9 ms in the detection task of Pilz and colleagues (2012), who tested 60 people, and 14 ms in an online letter task with 264 people (Francis and Thunell, 2022). Both of the later studies found it larger with lying rectangles than with upright ones, so the score is also given for each orientation. Taken one at a time, only 2 of Pilz and colleagues' 60 people showed a significant benefit with lying rectangles and 3 with upright ones, so one person's benefit is not meaningful: read it across a group, which Francis and Thunell put at hundreds of people.
Scores
- Same-Object Benefitms
- Mean detection time at the near end of the other rectangle minus at the far end of the cued rectangle. The two ends are the same distance from the cue.
- Positive values mean attention moved faster within the cued rectangle
- Same-Object Benefit, Lying Rectanglesms
- The benefit on trials with the rectangles one above the other.
- Positive values mean attention moved faster within the cued rectangle
- Same-Object Benefit, Upright Rectanglesms
- The benefit on trials with the rectangles side by side.
- Positive values mean attention moved faster within the cued rectangle
- Cue Benefitms
- Mean detection time at the far end of the cued rectangle minus at the cued end: a move of attention through space that stays on one object.
- Positive values mean the cue speeded detection at its own end
- Detection Time, Cued Endms
- Mean detection time when the target filled the cued end.
- Lower is faster
- Detection Time, Same Rectanglems
- Mean detection time when the target filled the far end of the cued rectangle.
- Lower is faster
- Detection Time, Other Rectanglems
- Mean detection time when the target filled the near end of the other rectangle.
- Lower is faster
- Same-Object Benefit, Mediansms
- Median detection time at the near end of the other rectangle minus at the far end of the cued rectangle.
- Positive values mean attention moved faster within the cued rectangle
- Targets Detected%
- Share of trials with a target answered with a press at or after 100 ms from the target, with no press before it.
- Higher is better
- Presses Without a Target%
- Share of catch trials with a press.
- Lower is better; over a quarter is flagged
- Mean Detection Timems
- Mean detection time over all trials with a target.
- Lower is faster
- Cued-End Detections Usedtrials
- Detections at the cued end.
- Informational
- Same-Rectangle Detections Usedtrials
- Detections at the far end of the cued rectangle, the trials the benefit uses.
- Fewer than 12 is flagged
- Other-Rectangle Detections Usedtrials
- Detections at the near end of the other rectangle, the trials the benefit uses.
- Fewer than 12 is flagged
- Missed Targetscount
- Trials with a target and no press within 2,000 ms.
- Lower is better
- Presses Before the Targetcount
- Trials with a press before the target appeared, or before the moment it would have appeared on a catch trial.
- Lower is better
- Anticipationscount
- Presses under 100 ms from the target's onset.
- Lower is better
- Trials With a Targettrials
- Trials with a target in the scored run.
- Informational
- Catch Trialstrials
- Trials with no target in the scored run.
- Informational
- Total Trialstrials
- Trials in the scored run.
- Informational
Use and evidence
49 papers from 2021 to 2025 name this task in their title or abstract, up 29% compared with 2016 to 2020. That ranks it 307 of 495 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 8 |
| 2024 | 8 |
| 2023 | 8 |
| 2022 | 14 |
| 2021 | 11 |
| 2020 | 10 |
| 2019 | 12 |
| 2018 | 2 |
| 2017 | 6 |
| 2016 | 8 |
| 2015 | 9 |
| 2014 | 3 |
| 2013 | 6 |
| 2012 | 7 |
| 2011 | 10 |
| 2010 | 21 |
| 2009 | 3 |
| 2008 | 4 |
| 2007 | 3 |
| 2006 | 3 |
| 2005 | 5 |
| 2004 | 6 |
| 2003 | 1 |
| 2002 | 2 |
| 2001 | 1 |
| 2000 | 1 |
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
- 16
- 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 0.22.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Display
- Two outlined rectangles, 320 by 64 px, around a central cross: side by side on half the trials and one above the other on the rest. Their ends sit on the corners of a 256 px square.
- Before the cue
- The cross alone for 500 ms, then the rectangles for 1,000 ms.
- Cue
- The outline of one end brightens for 100 ms.
- Cue to target
- A 200 ms gap, 300 ms from the start of the cue.
- Target
- A white square fills an end, until a press or 2,000 ms.
- Key
- The space bar for every target. A press before the target, or under 100 ms after it, is not a detection.
- Trial mix
- 192 trials with a target (standard; 128 to 384, in steps of 64): 75% at the cued end, 12.5% at the far end of the cued rectangle and 12.5% at the near end of the other rectangle, plus one catch trial with no target for every eight: 216 trials in all.
- Order
- A seeded random order with each end of each orientation cued equally often, saved with the trial data, and a break halfway. The displays switch on screen frames, and their measured durations are saved.
- Practice
- 12 trials, 2 of them with no target, with feedback for 800 ms. No feedback in the test.
- Score
- Mean detection time at the near end of the other rectangle minus at the far end of the cued rectangle.
The display, the cue and the target follow Egly, Driver and Rafal (1994), and the timing and the catch trials follow the detection task of Pilz and colleagues (2012), who gave 640 trials with a target over a session. This version has 192, with 24 at each of the two ends the score compares, to keep the session near 10 minutes. The benefit is small, and only 2 and 3 of Pilz and colleagues' 60 people showed it on their own, depending on orientation, so one person's benefit is not meaningful. Compare groups: Francis and Thunell (2022) estimate that a study needs hundreds of people. Scores are also given for each orientation, because both of those studies found the benefit larger with rectangles lying one above the other.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: object_based_attention_test from the scored run, press the space bar for a target (8 of every 9 trials) and withhold on catch trials with no target, within 2,000 ms. Responding mainly on catch trials invalidates; not separating targets from catch trials is flagged. Presses on over half the catch trials invalidate and on over a quarter are flagged. Presses before the target are held to the limit for responses under 100 ms. Fewer than 12 detections at either uncued end is flagged and withholds the percentile. Missed responses and responses under 100 ms follow the timed-test rule.
Why these rules
Responses concentrated on trials that needed none (one-sided Fisher exact test, p < .05) mean the instructions were reversed and invalidate; responses that do not separate the two trial types are flagged. Responding is the common, prepotent response here, so missing more than max(3, 25%) of response trials signals non-engagement (the platform's timed-test rule); any miss is flagged. Responses under 100 ms follow the timed-test rule. Catch trials show whether presses followed the targets, as in the detection task of Pilz and colleagues (2012); a press before the target cannot be a detection, so it is held to the limit for responses under 100 ms. The catch-trial limits and the minimum of 12 detections are ConductScience choices, the limits being those of the inhibition of return task.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Trials with a target | 192 | 128 to 384 |
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 Object-Based Attention Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Egly, Driver and Rafal, 1994; Pilz, Roggeveen, Creighton, Bennett and Sekuler, 2012), with the standard settings (trials with a target: 192). The main score was same-object benefit (mean detection time at the near end of the other rectangle minus at the far end of the cued rectangle).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Egly, R., Driver, J., & Rafal, R. D. (1994). Shifting visual attention between objects and locations: Evidence from normal and parietal lesion subjects. Journal of Experimental Psychology: General, 123(2), 161-177. https://doi.org/10.1037/0096-3445.123.2.161The paradigm: after a cue at one end of a rectangle, a target on that rectangle is detected faster than one the same distance away on the other rectangle.
- Pilz, K. S., Roggeveen, A. B., Creighton, S. E., Bennett, P. J., & Sekuler, A. B. (2012). How prevalent is object-based attention? PLoS ONE, 7(2), e30693. https://doi.org/10.1371/journal.pone.0030693The timing, the trial mix and the catch trials. Detection benefit of 9 ms, with few individuals showing it on their own.
- Francis, G., & Thunell, E. (2022). Excess success in articles on object-based attention. Attention, Perception, & Psychophysics, 84(3), 700-714. https://doi.org/10.3758/s13414-022-02459-6An online study of 264 people: a 14 ms benefit, 33 ms with lying rectangles and none with upright ones, and the sample sizes it calls for.
- Lamy, D., & Egeth, H. (2002). Object-based selection: The role of attentional shifts. Perception & Psychophysics, 64(1), 52-66. https://doi.org/10.3758/BF03194557The benefit depends on a shift of attention within the trial, which the cue calls for.
- Chen, Z. (2012). Object-based attention: A tutorial review. Attention, Perception, & Psychophysics, 74(5), 784-802. https://doi.org/10.3758/s13414-012-0322-zA review of the paradigm and what changes the benefit.
Source papers
- Francis G, Thunell E (2022). Excess success in articles on object-based attention. Attention, Perception, & Psychophysics, 84(3):700-714.Paradigm source, University students
Questions
How long does the Object-Based Attention Task take?
About 9 to 11 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?
Same-Object Benefit, Same-Object Benefit, Lying Rectangles, Same-Object Benefit, Upright Rectangles, Cue Benefit, Detection Time, Cued End, Detection Time, Same Rectangle, Detection Time, Other Rectangle, Same-Object Benefit, Medians, Targets Detected, Presses Without a Target, Mean Detection Time, Cued-End Detections Used, Same-Rectangle Detections Used, Other-Rectangle Detections Used, Missed Targets, Presses Before the Target, Anticipations, Trials With a Target, Catch Trials and Total Trials. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Object-Based Attention Task used in research?
49 papers from 2021 to 2025 name it in their title or abstract, up 29% compared with 2016 to 2020. That ranks it 307 of 495 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.22.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Object-Based Attention 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 with a target (128 to 384). 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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