Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Last Modified: January 12, 2026 by K. Borchert (katjab@millisecond.com), Millisecond
Script Copyright © Millisecond Software, LLC
This script implements the Digit Span procedure, a measure of working memory, with two main measures the Two Error Maximal Lenght (teML), which is the traditional digit span measure, and a new measure MeanSpan (MS), the digit span that a participant is supposed to get correct 50% of the time.
The implemented procedure is based on Woods et al (2011).
Woods, D.L. et al (2011). Improving digit span assessment of short-term verbal memory. Journal of Clinicial and Experimental Neuropsychology, 33, 101-111
8 minutes
Participants see digit sequences and have to recall them in the order presented by selecting the digits from a circle of digits with the mouse. Depending on performance, participants move up a level or down a level. Assessment is over after 14 trials.
Overview of procedure implemented:
see section Editable Stimuli/Editable Lists
Instructions are not original to the task. They are provided by Millisecond.
Change instructions in helper file "digitspanvisual_instructions_inc.iqjs"
File Name: digitspan_summary*.iqdat
| Name | Description |
|---|---|
| inquisit.version | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| computer.touch | 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities |
| computer.hasKeyboard | 0 = no external keyboard detected; 1 = external keyboard detected |
| startDate | Date the session was run |
| startTime | Time the session was run |
| subjectId | Participant ID |
| groupId | Group number |
| sessionId | Session number |
| elapsedTime | Session duration in ms |
| completed | 0 = Test was not completed 1 = Test was completed |
| fTEML | Two-error maximum length, the traditional measure of a participant's FORWARD digit span. It is the last digitspan a participant gets correct before making two consecutive errors. |
| fTETT | Two-error total trials, the number of trials before FORWARD teML is reached (measure of consistency) |
| fML | Maximal FORWARD digit span that a participant recalled correctly during all 14 trials |
| fMS | The FORWARD digit span that a participant is expected to get correct 50% of all times based on overall performance during all 14 trials. |
| fCountPracticeTrials | The number of forward practice trials presented until a correct response (or task was aborted prematurely) |
File Name: digitspanvisual_raw*.iqdat
| Name | Description |
|---|---|
| build | Inquisit version number |
| computer.platform | Device platform: win | mac |ios | android |
| computer.touch | 0 = device has no touchscreen capabilities; 1 = device has touchscreen capabilities |
| computer.hasKeyboard | 0 = no external keyboard detected; 1 = external keyboard detected |
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| blockcode | The name the current block (built-in Inquisit variable) |
| blocknum | The number of the current block (built-in Inquisit variable) |
| trialcode | The name of the currently recorded trial (built-in Inquisit variable) |
| trialnum | The number of the currently recorded trial (built-in Inquisit variable) trialnum is a built-in Inquisit variable; it counts all trials run even those that do not store data to the data file. |
| practice | 1 = practice 0 = test |
| assessType | 0 for Forward |
| list.digitSequences.currentValue | The selected sequence |
| list.digitSequences.currentIndex | The index of the current sequence |
| n | The number of digits presented in a trial |
| countTrials | Counts the trials run in the current assessment |
| sequence | The digit sequence presented |
| correctSolution | The correct digit sequence |
| proposedSolution | The entered digit sequence |
| acc | 1 = proposed solution is correct; 0 = otherwise |
| conErrorCount | Consecutive error count on the current level |
| teML | Two-error maximum length, the traditional measure of a participant's digit span for the current forward assessment It is the last digitspan a participant gets correct before making two consecutive errors. -> it's '-1' until it's set (and once it's set it it should not change anymore) |
| teTT | Two-error total trials, the number of trials before teML is reached for the current forward assessment (measure of consistency) -> it's -1 until it's set (and once it's set it should not change anymore) |
| ml | Maximal digit span that a participant recalled correctly during all 14 trials of the current forward assessment the ML, it's 0 until participant recalls digit sequences correctly. The ML is subject to change throughout all 14 trials. The last ML recorded represents the participant's actual ML. |
| ms | The estimated digit span for the current forward assessment that a participant is expected to get correct 50% of all times based on overall performance during all 14 trials. -> it's 0 until it's calculated at the end of a block. A value < 3 only happens if participant repeatedly failed on level 3(2). |
The procedure can be adjusted by setting the following parameters.
| Name | Description | Default |
|---|---|---|
Design Parameters |
||
| minPracticeTrials | Minimum number of practice trials before a participant can move towards test with a correct response | 2 |
| maxPracticeTrials | Maximum number of practice trials run until either a correct responses is given or the task is aborted | 8 |
| fStartN | The starting span size for the forward span (select from 3-16) | 3 |
| fEndN | The last span size tested for the forward span (select from 3-16) | 16 |
Sizing Parameters |
||
| circleProportion | Proportion of canvas height used for the circle radius of response buttons | 0.3 |
Timing Parameters |
||
| digitDurationMS | The StimulusOnsetAsynchrony (in ms) for each digit | 1000 |
| posFeedbackDurationMS | The duration (in ms) of the positive feedback stim during practice | 3000 |
Debugmode: Make Sure It's Set To 0 For Actual Testing |
||
| debugmode | 1 = script presents the correct solutions (debugmode) 0 = no correct solutions are presented | 0 |