Attention
Kinetic Depth Task
Also called: kinetic depth effect, structure from motion, shape from motion, KDE, SFM
Measure how moving dots reveal a three-dimensional shape. Participants identify a sphere or cylinder, with static displays as a comparison.
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. Try it here first, with no account.
- Papers, 2021 to 2025
- 8
- Evidence grade
- D
- Registered clinical studies
- 1
What it measures
Identify a sphere or cylinder from moving dots seen through a small window. Static dot displays provide a comparison for shape judgments without motion. Scores accuracy for moving shapes and its difference from the static baseline.
Constructs
- Structure from motion
- Visual shape perception
- Kinetic depth
Research uses
- Research on shape perception from motion
- Group comparisons of visual processing
How the paradigm works
Moving dots can reveal a three-dimensional shape even when a single view cannot. This task asks participants to identify a sphere or a vertical cylinder from an original generated dot field. Both start with the same distribution of projected dot positions, while hidden depth controls the subsequent motion.
More about the paradigm
Each display lasts 2400 ms behind a fixed rectangular window. Two shapes, 80 or 160 starting dots, and moving or static presentation make eight conditions, each repeated 8 times in the standard 64-trial session. Six moving practice displays give feedback. The left/right shape mapping and trial order are seeded. Answers follow display offset, with no time limit.
The primary measure is moving-shape accuracy, with static accuracy and the motion benefit as secondary measures. Shape judgments include changing motion and dot-density cues, not a pure estimate of one visual mechanism. Screens differ in size and timing; compare sessions on similar equipment. This research task provides no clinical classification and needs no calibration.
Scores
- Moving Shape Accuracy%
- Share of usable moving displays whose shape was identified correctly.
- Higher means more correct shape judgments
- Static Shape Accuracy%
- Accuracy on static projections, which carry no shape information.
- About 0.5 is expected
- Motion Benefit%
- Moving accuracy minus static accuracy.
- Positive means more correct shape judgments with motion
- Moving Accuracy With 80 Dots%
- Moving shape accuracy with 80 starting dots.
- Higher means more correct judgments
- Moving Accuracy With 160 Dots%
- Moving shape accuracy with 160 starting dots.
- Higher means more correct judgments
- Median Answer Timems
- Median time from display offset to a moving-shape answer.
- Informational
- Anticipationscount
- Answers under 100 ms, excluded from accuracy and answer time.
- Lower is better
- Early Key Pressescount
- Arrow keys pressed while the dots were still visible, ignored.
- Informational
- Frame Intervalms
- Median measured screen-frame interval.
- About 16.7 ms at 60 Hz
- Dropped Frames%
- Share of expected display frames skipped.
- Above 0.05 is flagged
- Display Durationms
- Median measured duration of the dot display.
- About 2400 ms
- Completed Trialstrials
- Answered test displays in the selected run.
- Fewer than planned is flagged
- Planned Trialstrials
- Number of planned test displays.
- Informational
Use and evidence
8 papers from 2021 to 2025 name this task in their title or abstract, down 47% compared with 2016 to 2020. That ranks it 460 of 495 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 2 |
| 2024 | 1 |
| 2023 | 2 |
| 2022 | 2 |
| 2021 | 1 |
| 2020 | 1 |
| 2019 | 5 |
| 2018 | 3 |
| 2017 | 2 |
| 2016 | 4 |
| 2015 | 0 |
| 2014 | 3 |
| 2013 | 5 |
| 2012 | 5 |
| 2011 | 2 |
| 2010 | 9 |
| 2009 | 5 |
| 2008 | 4 |
| 2007 | 2 |
| 2006 | 3 |
| 2005 | 3 |
| 2004 | 2 |
| 2003 | 1 |
| 2002 | 1 |
| 2001 | 1 |
| 2000 | 0 |
Use grade E
Fewer than 30 papers from 2021 to 2025.
Evidence grade D
Little published measurement evidence found.
- Papers on test-retest reliability
- 0
- Papers on reliability or validity
- 3
- Registered clinical studies using it as an outcome
- 1
Note on the counts: Original generated sphere/cylinder shape judgments; matched static baseline; no clinical classification..
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 3 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Display
- 80 or 160 white starting dots behind a fixed 120 by 196.8 px window on a 320 by 260 px dark panel. A sphere or cylinder turns back and forth around a vertical axis through 35 degrees each way.
- Timing
- 500 ms fixation, then 2400 ms of moving or static dots. Answer after the dots disappear, with no time limit. Frame intervals, display duration and dropped frames are recorded.
- Trials
- 64 standard: 8 per shape, dot count and motion condition. The setting permits 6 to 16 repeats, giving 48 to 128 tests in a seeded mixed order.
- Practice
- 6 moving displays with feedback for 1000 ms each. Short breaks after every 32 tests.
- Response
- Left or right arrow, or click the corresponding shape. The shape assigned to each side is fixed within the session and seeded across sessions.
- Scores
- Moving-shape accuracy; static accuracy; moving minus static accuracy; moving accuracy by dot count; answer time and timing quality. Answers under 100 ms are excluded.
Our generated displays use uniform projected starting positions and a common window, rather than the complete silhouettes and rating scales in the source. Moving dots can reveal both motion and density cues. Screens differ; use similar equipment for comparisons. No calibration or clinical classification.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: kinetic_depth_test from the scored run. Shape answers to moving displays have two choices. Static displays are a baseline without shape information and are excluded from accuracy validity checks. An incomplete run or poor frame timing is flagged. Responses under 100 ms follow the timed-test rule.
Why these rules
Shape is defined by changing dot positions. Static projections are matched across shapes, so chance performance there is expected. Moving shape judgments can be difficult, so accuracy is descriptive rather than a clinical threshold. The frame schedule is part of the stimulus.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Trials per shape, density and motion condition | 8 | 6 to 16 |
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 Kinetic Depth Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Dosher, Landy and Sperling, 1989), with the standard settings (trials per shape, density and motion condition: 8). The main score was moving shape accuracy (share of usable moving displays whose shape was identified correctly).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Dosher, B. A., Landy, M. S., & Sperling, G. (1989). Ratings of kinetic depth in multidot displays. Journal of Experimental Psychology: Human Perception and Performance, 15(4), 816-825. https://doi.org/10.1037/0096-1523.15.4.816Sphere and cylinder dot displays, with separate judgments of depth, rigidity and coherence. Our task measures shape identification.
Source papers
- Dosher, B. A., Landy, M. S., & Sperling, G. (1989). Ratings of kinetic depth in multidot displays. Journal of Experimental Psychology: Human Perception and Performance, 15(4), 816-825.Paradigm source, Adults
Questions
How long does the Kinetic Depth 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?
Moving Shape Accuracy, Static Shape Accuracy, Motion Benefit, Moving Accuracy With 80 Dots, Moving Accuracy With 160 Dots, Median Answer Time, Anticipations, Early Key Presses, Frame Interval, Dropped Frames, Display Duration, Completed Trials and Planned Trials. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Kinetic Depth Task used in research?
8 papers from 2021 to 2025 name it in their title or abstract, down 47% compared with 2016 to 2020. That ranks it 460 of 495 test families in the ConductCognition test census (use grade E). Source: ConductCognition test census 0.22.0, counted 3 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Kinetic Depth Task have?
In the published research, 0 papers report its test-retest reliability and 1 registered clinical study uses 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 per shape, density and motion condition (6 to 16). 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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