Number Stroop Task
A numerical variant of the Stroop task measuring interference between enumeration and digit reading, requiring participants to report quantity while ignoring digit identity.
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.
Measures: Executive function, inhibitory control, enumeration speed, numerical processing, and the ability to suppress automatic digit reading in favor of quantity judgment.
- 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
| responsetype | Response method: 'keyboard', 'keypad', 'audio', or 'choose' (ask participant at start). (default: keyboard) |
| scorerealtime | For audio responses: set to 1 to score responses with keyboard in real-time. Otherwise responses must be coded afterward. (default: 0) |
| usepreset | If 1, use same sequence of stimuli every time. If 0, regenerate randomly on each run. (default: 1) |
| fixationTime | Time for the fixation cross in milliseconds. (default: 1000) |
| responseTimeout | Time limit given for responding in milliseconds. (default: 2000) |
| voicekeythreshold | Voice key threshold for audio responses (may need adjustment based on microphone). (default: 0.35) |
| voiceKeyDuration | Voice key duration in milliseconds. (default: 200) |
| saveAudio | Should the audio buffer be saved for audio responses? (default: 1) |
| compressAudio | Command to compress audio files. (default: 0) |
| compressor | Compressor command for audio compression. (default: oggenc ) |
| Validation | preliminary |
| Psychometric data | Not available |
| Normative data | Not available |
| subnum | test | response | code | block | trial | stim | cond | responded | response | correct | abstime | rt | speechduration | recordtime |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 19 | number-stroop | keyboard | data/19/trial-000- | 0 | 0 | G | N | 1 | 1 | 1 | 22399 | 1275 | 0 | 1275 |
| 19 | number-stroop | keyboard | data/19/trial-001- | 0 | 1 | 333 | C | 1 | 3 | 1 | 25187 | 732 | 0 | 732 |
| 19 | number-stroop | keyboard | data/19/trial-002- | 0 | 2 | 3 | I | 1 | 3 | 0 | 27432 | 461 | 0 | 461 |
| 19 | number-stroop | keyboard | data/19/trial-003- | 0 | 3 | MMM | N | 1 | 3 | 1 | 29406 | 609 | 0 | 609 |
| 19 | number-stroop | keyboard | data/19/trial-004- | 0 | 4 | GG | N | 1 | 2 | 1 | 31538 | 554 | 0 | 554 |