Simon Task
System Requirements
Minimum: 800×600
Recommended: 1024×768
Description
Simon's spatial stimulus-response compatibility task. Participants respond to stimulus color while ignoring its spatial location, demonstrating automatic processing of task-irrelevant spatial information.
Measures: Selective attention, inhibitory control, color processing, spatial stimulus-response compatibility, reaction time
attention executive function inhibitory control
Ages: 7+ · Populations: adults, children, research, clinical
About This Test
Participants see colored circles (default: red or blue) appearing at different horizontal positions on the screen. They respond to the color using left/right shift keys, ignoring the horizontal position. The spatial position creates compatibility conditions: compatible (color and position match), incompatible (color and position conflict), or neutral (stimuli appear near center). The task measures selective attention and inhibition of automatic spatial responses.
- Colorblind individuals may have difficulty with default red-blue colors. Alternative color pairs (e.g., yellow/blue) can be configured via parameters.
- Demo mode uses 3 repetitions (42 trials, ~3-4 minutes) vs standard 10 repetitions (140 trials, ~10 minutes)
Test Details
simonsimon.pbl🚀 Try Without Registration
Run this test immediately without creating an account. Data stays in your browser.
Researcher Access Benefits
To save configurations, upload data, use translations, track completion, and manage studies, please log in or register for an account.
Scientific Background
Original Task References:
These references describe the original task that this PEBL implementation is based on.
- Simon, J. R., & Wolf, J. D. (1963). Choice reaction times as a function of angular stimulus-response correspondence and age. Ergonomics, 6, 99-105.
- Yamaguchi, M., & Proctor, R. W. (2012). Multidimensional vector model of stimulus-response compatibility. Psychological Review, 119, 272-303.
PEBL-Specific References:
These studies used the PEBL version of this task.
- Mueller, S. T. (2011). The PEBL Simon Interference Task. Computer software retrieved from http://pebl.sf.net/battery.html
Validation status: Not-validated
Related Tests
Data Output
Creates two data files: (1) simon-<SUBNUM>.csv with trial-level data including stimulus type, position, compatibility, response, correctness, timestamps, and reaction times; (2) simon-summary-<SUBNUM>.txt with summary statistics organized by compatibility condition and by position/stimulus combinations.
Key Variables
| Variable | Description |
|---|---|
| compatible | Compatibility condition: 1=compatible (color and position match), 0=neutral (center positions), -1=incompatible (color and position conflict) |
| pos | Horizontal position in pixels from screen center: -200, -100, -50, 0, 50, 100, 200 |
| rt | Reaction time in milliseconds from stimulus onset to response |
| corr | Response accuracy: 1=correct, 0=incorrect |
Example Data
example-data.csv Primary
Trial-by-trial data with columns: subnum, trial, type (1=left color, 2=right color), pos (horizontal position in pixels from center, -200 to +200), compatible (1=compatible, 0=neutral, -1=incompatible), resp (key pressed: <lshift> or <rshift>), corr (1=correct, 0=incorrect), time (absolute timestamp in ms), rt (reaction time in ms)
| subnum | trial | type | pos | compatible | resp | corr | time | rt |
|---|---|---|---|---|---|---|---|---|
| example | 1 | 2 | 50 | 1 | <rshift> | 1 | 19130 | 364 |
| example | 2 | 2 | -200 | -1 | <rshift> | 1 | 20181 | 479 |
| example | 3 | 1 | -50 | 1 | <lshift> | 1 | 21460 | 402 |
| example | 4 | 2 | -100 | -1 | <lshift> | 0 | 22648 | 379 |
| example | 5 | 2 | -200 | -1 | <lshift> | 0 | 23718 | 523 |
| example | 6 | 2 | -50 | -1 | <rshift> | 1 | 24901 | 383 |
| example | 7 | 1 | -100 | 1 | <lshift> | 1 | 26014 | 403 |
| example | 8 | 1 | 0 | 0 | <lshift> | 1 | 27026 | 454 |
| example | 9 | 2 | 200 | 1 | <rshift> | 1 | 28091 | 424 |
example-data-summary.txt Summary
Summary statistics including: response times by compatibility condition (-1, 0, 1), response times by position/condition combinations, accuracy by compatibility, accuracy by position/condition. Each section reports N, median, mean, and SD.
PEBL Simon Test: Summary data PEBL Version 2.2 Thu Nov 27 21:01:20 2025 Response times (by compatibility): condition N median mean sd --------------------------------- -1 24 382 455.333 181.053 0 8 395.5 523.875 302.224 1 24 407.5 429.042 103.884 Response times (by position/Condition): condition N median mean sd --------------------------------- 1|-200 4 557.5 535 159.256 1|-100 4 408.5 398.75 54.0619 1|-50 4 373.5 375.75 31.4514 1|0 4 431 612.25 387.301 1|50 4 539.5 640.5 312.321 1|100 4 385.5 381.25 37.2114 1|200 4 379.5 402.75 96.0192 2|-200 4 501 529.75 145.495 2|-100 4 378 369.75 16.0838 2|-50 4 365.5 408 97.2754 2|0 4 380.5 435.5 130.6 2|50 4 439 446.75 77.9563 2|100 4 452.5 441.25 96.1727 2|200 4 389.5 376.75 44.3699 Accuracy (By compatibility): condition N median mean sd --------------------------------- -1 24 1 0.625 0.484123 0 8 1 1 0 1 24 1 0.916667 0.276385 Accuracy (By position/condition): condition N median mean sd --------------------------------- 1|-200 4 1 0.75 0.433013 1|-100 4 1 1 0 1|-50 4 1 1 0 1|0 4 1 1 0 1|50 4 1 1 0 1|100 4 0.5 0.5 0.5 1|200 4 0.5 0.5 0.5 2|-200 4 0.5 0.5 0.5 2|-100 4 0.5 0.5 0.5 2|-50 4 1 0.75 0.433013 2|0 4 1 1 0 2|50 4 1 1 0 2|100 4 1 0.75 0.433013 2|200 4 1 1 0
Sample data showing typical output format. Actual values will vary by participant.
About This Test
Simon's spatial stimulus-response compatibility task. Participants respond to stimulus color while ignoring its spatial location, demonstrating automatic processing of task-irrelevant spatial information.
Category: Attention
Estimated Duration: 10 minutes
Available Translations: 8 languages
Documentation Sources:
Test description file, Test implementation, PEBL wiki archive, Parameter schema
Documentation Status: Standard