Attention
Line Bisection Test
Also called: line bisection task, Schenkenberg line bisection
Measure spatial attention as participants mark the middle of lines on the left, in the center and on the right, scored as the deviation from the true middle.
3-5 minUntimed
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
- 224
- Evidence grade
- B
- Registered clinical studies
- 68
What it measures
Measures how attention is spread between the left and right of space. Lines of six lengths appear one at a time on the left, in the center and on the right, and participants mark the middle of each. The main score is the mean deviation of the marks from the true middle, with rightward deviations positive.
Constructs
- Spatial attention
- Visuospatial judgment
- Attentional bias between left and right
Research uses
- Spatial attention and neglect research
- Pseudoneglect and aging research
- Within-study group comparison
How the paradigm works
The line bisection test measures how attention is spread between the left and right of space. Horizontal lines appear one at a time, and participants click or tap the exact middle of each. Before each line they press Next line, a button centered below the field, so every movement starts from the middle of the screen. Each line gets one mark, which cannot be changed, and there is no time limit.
More about the paradigm
The 18 lines follow Schenkenberg, Bradford and Ajax (1980): six lengths in the ratio 100 to 200, each shown once on the left, once in the center and once on the right of the field. The longest line spans 45% of the field width. Left and right lines are centered a quarter of the width from each side, so each lies wholly in its half. The order is drawn from the session's random seed, with no more than three lines in a row at one position, and a study can run up to three sets. Two practice lines come first; the mark is confirmed, but the true middle is not shown, so practice does not train the bias away. Each mark is saved with the line's ends as shares of the field width and the field's size in pixels.
Each mark's deviation is its distance from the true middle as a percentage of half the line, positive to the right (Schenkenberg et al. 1980). The main score is the mean deviation over all lines. The mean is also given for left, center and right lines and for short and long lines. Healthy adults tend to bisect slightly left of the true middle, a bias called pseudoneglect, and older adults less so (Jewell and McCourt 2000). In neglect after right-hemisphere damage, marks move away from the neglected left side. The scores support research on spatial attention and do not diagnose neglect.
Scores
- Mean Deviation%
- Mean distance of the marks from the true middle, as a percentage of half the line; marks right of the middle are positive.
- Positive values mean marks to the right; healthy adults are often slightly negative
- Mean Absolute Deviation%
- Mean size of the deviation, whatever its direction.
- Lower means marks closer to the true middle
- Left Line Deviation%
- Mean deviation on the six lines in the left half of the field.
- Compare with the center and right lines
- Center Line Deviation%
- Mean deviation on the six lines in the center of the field.
- Compare with the left and right lines
- Right Line Deviation%
- Mean deviation on the six lines in the right half of the field.
- Compare with the left and center lines
- Short Line Deviation%
- Mean deviation on the three shortest lengths (100 to 140).
- Compare with long lines; the difference shows the effect of line length
- Long Line Deviation%
- Mean deviation on the three longest lengths (160 to 200).
- Compare with short lines; the difference shows the effect of line length
- Lines Bisectedcount
- Lines with a scored mark.
- 18 per set when every line is scored
- Marks Beyond the Line Endcount
- Marks placed past either end of the line.
- Above 0 means some lines were not bisected
- Presses Off the Linecount
- Presses away from the line, which marked nothing.
- Lower means fewer missed presses
- Anticipationscount
- Marks made under 100 ms after the line appeared, left out of every other score.
- Above 0 means some marks came before the line could be seen
- Median Time to Markms
- Median time from the line appearing to the mark.
- Lower is faster; speed is not the aim of the task
Use and evidence
224 papers from 2021 to 2025 name this task in their title or abstract, down 22% compared with 2016 to 2020. That ranks it 113 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 43 |
| 2024 | 42 |
| 2023 | 54 |
| 2022 | 41 |
| 2021 | 44 |
| 2020 | 50 |
| 2019 | 53 |
| 2018 | 67 |
| 2017 | 55 |
| 2016 | 62 |
| 2015 | 56 |
| 2014 | 66 |
| 2013 | 66 |
| 2012 | 67 |
| 2011 | 66 |
| 2010 | 60 |
| 2009 | 43 |
| 2008 | 39 |
| 2007 | 52 |
| 2006 | 57 |
| 2005 | 43 |
| 2004 | 36 |
| 2003 | 43 |
| 2002 | 50 |
| 2001 | 36 |
| 2000 | 42 |
Use grade C
100 to 299 papers from 2021 to 2025.
Evidence grade B
At least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers.
- Papers on test-retest reliability
- 19
- Papers on reliability or validity
- 97
- Registered clinical studies using it as an outcome
- 68
Published reliability
- Test-retest ICC .97 in stroke patients with neglect. (Bailey et al. 2004) https://doi.org/10.1080/09602010343000282
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.
- Lines
- 18 lines: six lengths in the ratio 100 to 200, each shown once on the left, in the center and on the right.
- Field
- The longest line spans 45% of the field width; left and right lines are centered a quarter of the width from each side.
- Start
- Next line, a button centered below the field, shows each line, so every movement starts from the middle.
- Response
- One click or tap on the line; the mark shows for 400 ms and cannot be changed. No time limit.
- Order
- Random order from the session's seed, with no more than three lines in a row at one position; 1 to 3 sets.
- Practice
- Two centered lines; the mark is confirmed, but the true middle is not shown.
The scores support research on spatial attention and do not diagnose neglect.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: line_bisection_test from the scored run, one per line. A mark has no correct position to compare with chance, so accuracy is not judged against chance. Marks within 200 ms of the line appearing on at least half the lines invalidate. Marks beyond the end of the line on 3 or more lines are flagged for review.
Why these rules
There is no correct option to compare with chance, so accuracy is not judged against chance. An answer under 200 ms is faster than a simple visual reaction, so it cannot reflect the item. Following response-time effort screening for untimed tests (Wise and Kong 2005), the session is invalid only when at least half the answers are that fast. A mark beyond the end of a line does not bisect it, so 3 or more such marks are flagged. A shift of the marks to one side never invalidates, because that shift is what the test measures.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Line sets | 1 | 1 to 3 |
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
- Untimed test: runs on desktops, laptops and tablets. 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 Line Bisection Test in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Schenkenberg, Bradford & Ajax, 1980), with the standard settings (line sets: 1). The main score was mean deviation (mean distance of the marks from the true middle, as a percentage of half the line; marks right of the middle are positive).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Schenkenberg, T., Bradford, D. C., & Ajax, E. T. (1980). Line bisection and unilateral visual neglect in patients with neurologic impairment. Neurology, 30(5), 509-517. https://doi.org/10.1212/WNL.30.5.509
- Jewell, G., & McCourt, M. E. (2000). Pseudoneglect: A review and meta-analysis of performance factors in line bisection tasks. Neuropsychologia, 38(1), 93-110. https://doi.org/10.1016/S0028-3932(99)00045-7
Source papers
- Schenkenberg T, Bradford DC, Ajax ET (1980). Line bisection and unilateral visual neglect in patients with neurologic impairment. Neurology, 30(5):509-517.Paradigm source, Adults
- Jewell G, McCourt ME (2000). Pseudoneglect: a review and meta-analysis of performance factors in line bisection tasks. Neuropsychologia, 38(1):93-110.Paradigm source, Adults
Questions
How long does the Line Bisection Test take?
About 3 to 5 minutes, as listed in the test library.
What device does a participant need?
Untimed test: runs on desktops, laptops and tablets. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Mean Deviation, Mean Absolute Deviation, Left Line Deviation, Center Line Deviation, Right Line Deviation, Short Line Deviation, Long Line Deviation, Lines Bisected, Marks Beyond the Line End, Presses Off the Line, Anticipations and Median Time to Mark. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Line Bisection Test used in research?
224 papers from 2021 to 2025 name it in their title or abstract, down 22% compared with 2016 to 2020. That ranks it 113 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 Line Bisection Test have?
In the published research, 19 papers report its test-retest reliability and 68 registered clinical studies use it as an outcome (evidence grade B in the ConductCognition test census). Test-retest ICC .97 in stroke patients with neglect. (Bailey et al. 2004)
Does it report a percentile?
No. Scores and quality flags only.
Which settings can a researcher change?
Line sets (1 to 3). 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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