Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond
Last Modified: January 05, 2025 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, D.L. et al (2011). Improving digit span assessment of short-term verbal memory. Journal of Clinicial and Experimental Neuropsychology, 33, 101-111
15 minutes
Participants see digit sequences and have to recall them in reversed order 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:
(1) Practice:
by default, participants have to go through at least 2 practice trials and at most 8 practice trials
until a correct response terminates the practice session and advances to the test session.
If no correct response is given within the maximum number of practice trials, the task terminates.
(2) Test
For the duration of 14 trials (based on Experiment 1, Woods et al, 2011), a participant sees a sequence of visual digits (starting with
level 3), where each digit is presented for 1 s. A visual signal is presented for the duration of 1s, after which the participant is asked to recall the
digit sequence and type the answer into a presented textbox.
If the response is correct (in digits and presentation order), the participant moves up to the next level (e.g. level 4).
If the response is incorrect, the same level is presented a second time.
If a consecutive error occurs the participant moves back down to a lower level, starting over.
The first time a participant makes a consecutive error, the traditional measure teML is set to the last correctly recalled number of digits
(e.g. if participant reaches level 8, but answers incorrectly both times, the teML is set to 7).
Because the digit span assessment does not exit when teML is set - as is done in traditional digit span assessments-
but goes on for the remainder of the 14 trials, it is possible for participants to superpass levels
they previously failed (e.g participant with teML = 7 may successfully recall 8 digits on a later try).
The new digit span assessment measure, ML, is set to the maximal length of digits correctly recalled during 14 trials.
Assessment is done for BACKWARD assessment (= recall the digits in reversed order).
Backward assessment starts at level 2
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 |
| 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 |
| bTEML | Two-error maximum length, the traditional measure of a participant's BACKWARDS digit span. It is the last digitspan a participant gets correct before making two consecutive errors. |
| bTETT | Two-error total trials, the number of trials before BACKWARD teML is reached (measure of consistency) |
| bML | Maximal BACKWARD digit span that a participant recalled correctly during all 14 trials. It is set to 0 before the start of the assessment. |
| bMS | The BACKWARD digit span that a participant is expected to get correct 50% of all times based on overall performance during all 14 trials. |
| bCountPracticeTrials | The number of backward 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 |
| date | Date the session was run |
| time | Time the session was run |
| subject | Participant ID |
| group | Group number |
| session | Session number |
| blockCode | Name of the current block |
| blockNum | Number of the current block |
| trialCode | Name of the current trial |
| trialNum | Number of the current trial |
| practice | 1 = practice 0 = test |
| assessType | 1 for Backward trials |
| 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 backward 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 backward 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 backward 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 backward 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 | 8 |
The Task Is Aborted (Default: 8) |
||
| bStartN | The starting span size for the backward span (select from 2-15) | 2 |
| bEndN | The last span size tested for the backward span (select from 2-15) | 15 |
Sizing Parameters |
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| circleProportion | 0.3 //proportion of canvas height used for the circle radius of response buttons (default: 0.3) | |
Timing Parameters |
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| 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 |
0 = No Correct Solutions Are Presented (Default) |
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