Number Stroop Task
System Requirements
Minimum: 800×600
Recommended: 1280×800
Description
A numerical variant of the Stroop task measuring interference between enumeration and digit reading, requiring participants to report quantity while ignoring digit identity.
Measures: Executive function, inhibitory control, enumeration speed, numerical processing, and the ability to suppress automatic digit reading in favor of quantity judgment.
Executive Function Attention Processing Speed
Ages: 7+ · Populations: adults, children, research, clinical, neuropsychological-assessment
About This Test
Modeled after Hernandez et al. (2010). Participants indicate how many items (1-3) appear on screen by pressing keys 1, 2, or 3, regardless of item identity. Stimuli include: (a) neutral letters (Z, MM, GGG), (b) congruent digits matching quantity (1, 22, 333), or (c) incongruent digits mismatching quantity (2, 33, 111). Each trial begins with a fixation cross (1000ms) followed by stimulus presentation (2000ms timeout). The task includes practice with feedback, followed by two test blocks without feedback. Keyboard response mode is standard.
- Numerical Stroop variant based on Hernandez et al. (2010) methodology
- Practice block (24 trials) with feedback, followed by two test blocks (84 trials each) without feedback
- Tests enumeration-digit interference rather than color-word interference
- Includes 9 language translations: English, German, Spanish, French, Italian, Korean, Dutch, Portuguese, Turkish
- Updated to PEBL 2.3 with Layout system, block counters, and version 1.0 (2026)
- The CSV header contains 'response' twice - column 2 shows response mode, column 9 shows actual response
Test Details
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Scientific Background
Original Task References:
These references describe the original task that this PEBL implementation is based on.
- Hernandez, A., Caño, A., & Costa, A. (2010). The role of cognitive control in bilingual language switching. Cognitive Psychology, 61(1), 1-24.
- Pavese, A., & Umiltà, C. (1998). Symbolic distance between numerosity and identity modulates Stroop interference. Journal of Experimental Psychology: Human Perception and Performance, 24(5), 1535-1545.
Validation status: Preliminary
Related Tests
Data Output
Creates multiple data files: (1) numstroop-keyboard-<subnum>.csv with trial-by-trial data, (2) numstroop-keyboard-summary-<subnum>.txt with performance statistics, (3) numstroop-keyboard-pooled.csv combining all participants, and (4) numstroop-sumall.csv with summary statistics.
Key Variables
| Variable | Description |
|---|---|
| subnum | Participant identifier code |
| block | Block number (0=practice, 1=first test block, 2=second test block) |
| trial | Trial number within block |
| stim | The stimulus displayed (e.g., '111', 'ZZZ', '2') |
| cond | Trial type: C=congruent, I=incongruent, N=neutral |
| responded | Whether participant responded (1=yes, 0=timeout) |
| response | Participant's response (1-3 for quantity) |
| correct | Response accuracy (1=correct, 0=incorrect) |
| rt | Response time in milliseconds |
About This Test
A numerical variant of the Stroop task measuring interference between enumeration and digit reading, requiring participants to report quantity while ignoring digit identity.
Category: Executive Function
Estimated Duration: 10 minutes
Available Translations: 9 languages
Documentation Sources:
Test description file, Test implementation, Parameter schema
Documentation Status: Complete