PEBL Hub — IRB Fact Sheet — 2026-08-23
Flanker Task
Category:Attention
Duration:~8 minutes
Parameters:9 configurable parameters available
Version:1.0
Input:Keyboard
Description
An implementation of the Eriksen Flanker Task, a test of selective attention and response inhibition where participants identify a central target while ignoring flanking distractors.
Participants respond to the direction of a central arrow while ignoring surrounding flanker arrows. Flankers can be congruent (same direction as target), incongruent (opposite direction), or neutral. The task includes practice trials followed by test blocks with an 800ms response deadline.
Key Parameters
| numreps | Number of repeats of 2x3 design (default: 20) |
| practicereps | Number of repetitions of desing in practice (default: 2) |
| includedashtrials | whether -->-- and --<-- trials should be included (default: 1) |
| includeemptytrials | whether [ > ] and [ < ] trials should be used (default: 1) |
| arrowsize | Pixel length of arrow (not head, entire arrow) (default: 40) |
| gap | pixel gap between arrows (default: 2) |
| fixationtime | Time prior to trial that fixation appears, in ms (default: 500) |
| timeout | Time allotted to make response, in ms (default: 800) |
| iti | Inter-trial interval; time between response and new trial strarting, in ms (default: 1000) |
| responsemode | Response method: auto (platform-aware), keyboardShift (L/R shift), keyboardSafe (Z/slash for web), mousetarget (click targets), mousebutton (L/R mouse buttons), userselect (custom key) (default: auto) |
Example Data Output (5 sample rows)
| subnum | test | block | trial | practice | targdir | flankercoherence | flankerdir | time0 | resp | corr | rt |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | flanker | 0 | 1 | 1 | -1 | -1 | 1 | 32539 | [<timeout>] | 0 | 802 |
| 1 | flanker | 0 | 2 | 1 | -1 | 1 | -1 | 34336 | <lshift> | 1 | 546 |
| 1 | flanker | 0 | 3 | 1 | 1 | 0 | 0 | 35889 | <rshift> | 1 | 503 |
| 1 | flanker | 0 | 4 | 1 | 1 | 1 | 1 | 37390 | <rshift> | 1 | 466 |
| 1 | flanker | 0 | 5 | 1 | -1 | NA | NA | 38835 | <lshift> | 1 | 559 |
References
Eriksen, C. W., & Schultz, D. W. (1979). Information processing in visual search: A continuous flow conception and experimental results. Perception & Psychophysics, 25(4), 249-263.
Stins, J. F., Polderman, T. J. C., Boomsma, D. I., & de Geus, E. J. C. (2007). Conditional accuracy in response interference tasks: Evidence from the Eriksen flanker task and the spatial conflict task. Advances in Cognitive Psychology, 3(3), 389-396.