PEBL Hub — IRB Fact Sheet — 2026-08-23
Item Order Task
Memory
Processing Speed
Category:Memory
Duration:~8 minutes
Parameters:6 configurable parameters available
Version:1.0
Description
A short-term memory task testing both item and order memory for consonant sequences.
A string of seven consonants is displayed briefly, then after a delay a second string appears. Participants judge whether the two strings are identical (same) or different (different). Differences can be an item replacement (a new letter substituted) or an order swap (two adjacent letters exchanged). Measures short-term memory for both item identity and sequential order.
Measures: Short-term memory, item memory, order memory
Key Parameters
| numSame | Number of 'same' trials (default: 20) |
| numDiffItem | Number of different trials with item substitution (default: 10) |
| numDiffOrder | Number of different trials with order swap (default: 10) |
| stimsize | Stimulus size. stimulus set must have enough to cover these (default: 7) |
| prestime | Presentation time, in ms, of stimulus (default: 2000) |
| delaytime | Delay time, in ms, between stimulus disappearing and response probe. (default: 2500) |
References
Lee, C. L., & Estes, W. K. (1977). Order and position in primary memory for letter strings. Journal of Verbal Learning and Verbal Behavior, 16(4), 395-418.
Lee, C. L., & Estes, W. K. (1981). Item and order information in short-term memory: Evidence for multilevel perturbation processes. Journal of Experimental Psychology: Human Learning and Memory, 7(3), 149.
Mueller, S. T. (2011). The PEBL Item Order Task. Computer software retrieved from http://pebl.sf.net/battery.html