PEBL Hub — IRB Fact Sheet — 2026-08-23
Even/Odd Classification Task
Executive Function
Processing Speed
Number Processing
Category:Executive Function
Duration:~8 minutes
Parameters:6 configurable parameters available
Version:1.0
Description
A brief number classification test in which participants judge whether a number is even or odd.
A simple classification task where participants view numbers between a configurable range (default 100-999) and respond whether each number is even or odd. The task measures basic numerical processing speed and accuracy. It serves as a good warm-up task or baseline measure of processing speed.
Measures: Number classification speed, basic numerical processing, simple decision making
Key Parameters
| reps | Number of trials of each condition (odd and even). Total trials will be twice this. (default: 10) |
| isi | Inter-stimulus interval in ms. (default: 500) |
| minval | smallest possible number to test. (default: 100) |
| maxval | largest possible number to test. (default: 999) |
| responsemode | Response method: auto (platform-aware), keyboardShift (L/R shift), keyboardSafe (Z/slash for web), arrowLR (left/right arrows), mousetarget (click targets), mousebutton (L/R mouse buttons), userselect (custom key) (default: auto) |
| responselabels | Semantic labels for left and right responses (default: Array) |
Data Output Columns
| subnum | Participant ID |
| trial | Trial number |
| starttime | Stimulus onset time (ms since test start) |
| number | Number displayed (range set by minval/maxval parameters) |
| isodd | Whether the number is odd (1) or even (0) |
| resp | Participant response (left or right, mapped to odd/even) |
| corr | Whether response was correct (1=correct, 0=incorrect) |
| rt | Response time in milliseconds |
References
Mueller, S. T. (2023). The PEBL Even-Odd Test. Computer software retrieved from http://pebl.sf.net/battery.html