PEBL Hub — IRB Fact Sheet — 2026-08-23

Plus-Minus Task

Executive Function Processing Speed

Category:Executive Function

Duration:~10 minutes

Parameters:2 configurable parameters available

Version:1.0

Description

A set-shifting task where participants add, subtract, and alternate between adding and subtracting a number from two-digit stimuli.

Participants complete three blocks of mental arithmetic. In the first block, they add a constant (default 3) to each number. In the second block, they subtract it. In the third block, they alternate between adding and subtracting on successive trials. The switch cost (difference between alternating and pure blocks) measures executive function and cognitive flexibility.

Measures: Executive function, set shifting, cognitive flexibility

Key Parameters

listsize	Number of math problems per list (default: 30)
addend	Value that should be added or subtracted in the problems. (default: 3)

Data Output Columns

sub	Participant ID
block	Block type: A (addition), S (subtraction), SW (switch/alternating)
trial	Trial number within the current block
value	The two-digit stimulus number presented
addend	The operation and value applied (e.g., +3 or -3)
corranswer	The typed response from the participant
answer	The correct answer
correct	Whether the response was correct (1) or incorrect (0)
corrcount	Cumulative correct count within the block
abstime	Absolute timestamp in milliseconds from the start of the test
rt	Response time in milliseconds from stimulus onset to Enter key

References

Jersild, A. T. (1927). Mental set and shift. Archives of Psychology, 89, 5-82.

Miyake, A., Friedman, N. P., Emerson, M. J., Witzki, A. H., Howerter, A., & Wager, T. D. (2000). The unity and diversity of executive functions and their contributions to complex 'frontal lobe' tasks: A latent variable analysis. Cognitive Psychology, 41(1), 49-100.

Mueller, S. T. (2011). The PEBL Plus-Minus Task. Computer software retrieved from http://pebl.sf.net/battery.html