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DIGIT SPAN (AUDITORY)
Script Author: Katja Borchert, Ph.D. (email@example.com) for Millisecond Software, LLC
last updated: 06-30-2020 by K. Borchert (firstname.lastname@example.org) for Millisecond Software, LLC
Script Copyright © 06-30-2020 Millisecond Software
This script implements the Digit Span procedure, a measure of working memory, with two main measures
the Two Error Maximal Lenght (TE_ML), 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
Participants hear digit sequences and have to recall them (in either a forward or backward manner)
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.
Note: by default, this script runs a forward and a backward assessment (in this order).
To run only one of the sessions, go to section Editable Parameters and change the default settings.
the default set-up of the script takes appr. 15 minutes to complete
DATA FILE INFORMATION
The default data stored in the data files are:
(1) Raw data file: 'digitspan_raw*.iqdat' (a separate file for each participant)
build: The specific Inquisit version used (the 'build') that was run
computer.platform: the platform the script was run on (win/mac/ios/android)
date, time, date and time script was run
subject, group, with the current subject/groupnumber
session: with the current session id
blockcode, blocknum: the name and number of the current block (built-in Inquisit variable)
trialcode, trialnum: the name and number of the currently recorded trial (built-in Inquisit variable)
Note: trialnum is a built-in Inquisit variable; it counts all trials run; even those
that do not store data to the data file.
assesstype: 0 for Forward and 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
con_errorcount: consecutive error count on the current level
TE_ML: the TE_ML, it's -1 until it's set (and once it's set it it should not change anymore)
TE_TT: the TE_TT, it's -1 until it's set (and once it's set it should not change anymore)
ML: 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 MS, 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) Summary data file: 'digitspan_summary*.iqdat' (a separate file for each participant)
computer.platform: the platform the script was run on (win/mac/ios/android)
script.startdate: date script was run
script.starttime: time script was started
script.subjectid: assigned subject id number
script.groupid: assigned group id number
script.sessionid: assigned session id number
script.elapsedtime: time it took to run script (in ms); measured from onset to offset of script
script.completed: 0 = script was not completed (prematurely aborted);
1 = script was completed (all conditions run)
fTE_ML = 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.
fTE_TT = Two-error total trials, the number of trials before FORWARD TE_ML 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.
bTE_ML = 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.
bTE_TT = Two-error total trials, the number of trials before BACKWARD TE_ML 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.
f_countPracticeTrials: the number of forward practice trials presented until a correct response (or task was aborted prematurely)
b_countPracticeTrials: the number of backward practice trials presented until a correct response (or task was aborted prematurely)
Overview of procedure implemented:
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 allowed, the task terminates.
For the duration of 14 trials (based on Experiment 1, Woods et al, 2011), a participant hears a sequence of auditory 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 TE_ML is set to the last correctly recalled number of digits
(e.g. if participant reaches level 8, but answers incorrectly both times, the TE_ML is set to 7). Because the digit span assessment does not exit when
TE_ML 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 TE_ML = 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 FORWARD assessment (= recall the digits in the order presented) and BACKWARD assessment (= recall the digits in reversed order).
Forward assessment starts at level 3
Backward assessment starts at level 2
by default, participant runs through the forward and then the backward assessment.
see section Editable Stimuli/Editable Lists
Instructions are not original to the task. They are provided by Millisecond Software
as htm/html pages and can be edited by changing the provided htm/html files.
To edit htm/html-files: open the respective documents in simple Text Editors such as TextEdit (Mac)
or Notepad (Windows).
check below for (relatively) easily editable parameters, stimuli, instructions etc.
Keep in mind that you can use this script as a template and therefore always "mess" with the entire code
to further customize your experiment.
The parameters you can change are:
/circleproportion: proportion of canvas height used for the circle radius of response buttons (default: 0.3)
/runForwardAssessment: true (1) = runs Forward Assessment (default); false (0) = skips Forward Assessment
/runBackwardAssessment: true (1) = runs Backward Assessment (default); false (0) = skips Backward Assessment
Note: if both assessments are run, forward assessment always precedes backward assessment
/minPracticeTrials: minimum number of practice trials before a participant can move towards test with a correct response
/maxPracticeTrials: maximum number of practice trials run until either a correct responses is given or
the task is aborted (default: 8)
/debugmode: 1 = script presents the correct solutions (debugmode); 0 = no correct solutions are presented (default)