Span Variants Test — IRB Fact Sheet

Description

A comprehensive battery of 9 working memory span tasks including forward/backward digit/letter/mixed spans and ordering tasks.

This replaces the the 'classic' digit span test from PEBL, with more variants that include running a series of letter/number/mixed span in forward/backward and ordered recall. dspan/digitspan allows running a single forward or backward span task, under a number of settings/parameters. These include auditory stimuli, procedure (staircase, small-to-large, and largest-to-smallest, control over presentation timing, and success criteria.

Key Parameters

forward_digit_order	Execution order for forward digit span (0=skip, else order number) (default: 1)
backward_digit_order	Execution order for backward digit span (0=skip, else order number) (default: 2)
forward_letter_order	Execution order for forward letter span (0=skip, else order number) (default: 0)
backward_letter_order	Execution order for backward letter span (0=skip, else order number) (default: 0)
forward_mixed_order	Execution order for forward mixed digit/letter span (0=skip, else order number) (default: 0)
backward_mixed_order	Execution order for backward mixed digit/letter span (0=skip, else order number) (default: 0)
digit_ordering_order	Execution order for digit ordering task (0=skip, else order number) (default: 0)
letter_ordering_order	Execution order for letter ordering task (0=skip, else order number) (default: 0)
mixed_ordering_order	Execution order for mixed ordering task (0=skip, else order number) (default: 9)
input	Input method: keyboard (top row numbers), keypad (numeric keypad), or mouse (default: keyboard)
UseAudio	Presentation mode: 0=video only, 1=audio+video, 2=audio only (works for digits and letters C,H,K,N,R,W,X,Y) (default: 1)
AllowBackspace	Allow users to backspace over responses (1=yes, 0=no) (default: 1)
AllowSkip	Allow users to skip over cells with '-' key (1=yes, 0=no) (default: 1)
responsemode	Layout response mode (use 'none' for manual keyboard input) (default: none)
version	Test progression type: 1=low-to-high (traditional), 2=high-to-low, 3=staircase (default: 1)
endearly	End list length when criterion is met (1=yes, 0=test all trials) (default: 0)
upperbound	The longest list length to test (default: 9)
lowerbound	The shortest list length to test (default: 3)
perlength	The number of trials at each length (default: 2)
criterion	Number of correct trials needed to proceed to next length (default: 1)
staircasestart	Starting list length for staircase method (version=3) (default: 4)
staircasetrials	Number of trials for staircase method (version=3) (default: 16)
ISI	Inter-stimulus interval in milliseconds (default: 1000)
iti	Inter-trial interval in milliseconds (default: 1500)
letter_set	Set of letters to use for letter span tasks (easily distinguishable, audio support for C,H,K,N,R,W,X,Y) (default: CHKNPQRWXY)

Scoring & Interpretation

Primary measure: Final span achieved for each task variant (final_span in pooled file). This represents the longest sequence correctly recalled.

Total correct: Sum of correct trials across all lengths (sumcorrect).

Progression: Tests can use low-to-high (traditional), high-to-low, or adaptive staircase methods (controlled by 'version' parameter).

The report file provides a convenient summary of all task results.

Example Data Output (5 sample rows)

subnum	tasktype	direction	stimulus_type	trialnum	length	try	input	response	resptime
example	forward_digit	forward	digit	1	3	0	465	456	1282
example	forward_digit	forward	digit	2	3	1	459	041	2311
example	backward_digit	backward	digit	1	3	0	917	719	2431
example	backward_digit	backward	digit	2	3	1	708	807	1264
example	forward_letter	forward	letter	1	3	0	RHN	NHR	3957

References

Based on classic digit span tasks with extensions for letters, mixed stimuli, and ordering variants commonly used in working memory research.