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

Two-Column Addition Test

arithmetic mental_calculation processing_speed working_memory numerical_processing

Category:Processing Speed

Duration:~10 minutes

Ages:7+

Populations:adults, adolescents, children (with adequate arithmetic skills), research participants, cognitive assessment batteries

Parameters:Four configurable parameters: numpractice (number of practice trials, default 10), numtrials (number of test trials, default 45), isi (inter-stimulus interval in ms, default 250), timeout (time limit per problem in ms, default 15000). All parameters are optional with sensible defaults.

Version:1.0

Description

Mental arithmetic task requiring rapid addition of three two-digit numbers presented vertically

The Two-Column Addition Test assesses mental arithmetic ability by requiring participants to rapidly add three two-digit numbers. **Procedure**: Three two-digit numbers (ranging from 11-99, no zeros) are presented vertically in columnar format. Participants must mentally calculate the sum and enter their answer using the keyboard number keys. The answer must be entered left-to-right (hundreds digit first, then tens, then ones if applicable). Participants can use backspace to correct mistakes before pressing Enter to confirm. **Timing**: Each problem has a 15-second time limit. If participants fail to respond within this time, a buzzer sounds and the next problem appears. Practice trials provide feedback on accuracy and response time; test trials do not. **Phases**: 1. **Practice Phase** (10 trials by default): Problems with feedback showing correct/incorrect and response time 2. **Test Phase** (45 trials by default): Problems without feedback **Scoring**: The test records accuracy, response time to first keypress, completion time, number of keystrokes, and whether timeout occurred. This provides measures of both speed and accuracy in mental arithmetic.

Measures: Mental calculation ability, arithmetic processing speed, working memory for numerical information, and performance under time constraints

Device requirements: Keyboard required for numeric input. Desktop or laptop computer recommended (tablet/mobile keyboard input may work but is less tested).

Notes

Part of the UTC-PAB (Unified Tri-Services Cognitive Performance Assessment Battery) as Test 4
Numbers are randomly generated (11-99 excluding any with 0 digits)
Buzzer sound (buzz500ms.ogg) plays on timeout
Instructions updated for web deployment with HTML-lite formatting and AdaptiveTextBox
Requires numeric keyboard input - not suitable for pure touch interfaces
Default timeout of 15 seconds is configurable via parameters
Practice trials provide accuracy feedback and completion time; test trials do not
LSL support added: markers for block start/end, stimulus onset, response submission/timeout, and trial accuracy
Available in 7 languages: English, German, Spanish, French, Italian, Dutch, Portuguese

Key Parameters

numpractice	Number of practice trials (default: 10)
numtrials	Number of testing trials (default: 45)
isi	ISI between tests (in ms) (default: 250)
timeout	Time (in ms) given to solve a problem. (default: 15000)

Scoring & Interpretation

Accuracy = proportion of corr=1 trials. Mean RT = average completetime for corr=1 trials. Timeout rate = proportion of toolong=1 trials. Initiation time = mean firstclick. Correction rate can be inferred from clicks > (answer_length + 1).