PEBL Hub — IRB Fact Sheet — 2026-08-23
Pattern Comparison (Sequential)
Memory
Processing Speed
Perception
Category:Processing Speed
Duration:~8 minutes
Parameters:9 configurable parameters available
Version:1.0
Description
A sequential pattern comparison task where participants memorize a dot pattern and then judge whether a second pattern is the same or different.
A dot grid pattern is displayed briefly, then erased. After a delay, a second pattern appears and participants judge whether it is the same as or different from the first. Measures visual short-term memory and pattern discrimination.
Measures: Visual short-term memory, pattern comparison, processing speed
Key Parameters
| similarfoil | should foil be similar to target (default: 1) |
| foildiff | Number of changes between target and foil (default: 3) |
| size | size of the target/foil matrices (default: 4) |
| givefeedback | Whether to give feedback (default: 1) |
| condsize | Number of trials per condition (x12) (default: 10) |
| prestime | presentation time in ms (default: 1500) |
| delay | Delay before judgment (default: 3500) |
| responsemode | Response method (default: auto) |
| responselabels | Semantic labels for responses (default: Array) |
Data Output Columns
| subnum | Participant ID |
| trial | Trial number |
| samediff | Whether the second pattern was the same as or different from the first (same/diff) |
| delta | Number of dot position differences between patterns (0 for same trials; 1, 2, or 3 for different trials) |
| mat1 | First (study) pattern encoded as a binary string (1=dot present, 0=empty) |
| mat2 | Second (test) pattern encoded as a binary string |
| abstime | Absolute timestamp in milliseconds from the start of the test |
| rt | Response time in milliseconds from when the second pattern appeared |
| resp | Participant response (same or different) |
| corr | Whether the response was correct (1) or incorrect (0) |
References
Perez, W. A., Masline, P. J., Ramsey, E. G., & Urban, K. E. (1987). Unified tri-services cognitive performance assessment battery: Review and methodology. DTIC/TR-87-007.
Mueller, S. T. (2011). The PEBL Pattern Comparison Task. Computer software retrieved from http://pebl.sf.net/battery.html