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DIGIT SPAN (AUDITORY)
Script Author: Katja Borchert, Ph.D. (firstname.lastname@example.org) for Millisecond Software, LLC
last updated: 08-02-2018 by K.Borchert (email@example.com) for Millisecond Software LLC
Copyright © 08-02-2018 Millisecond Software
This script implements the Digit Span procedure as described in:
Woods, D.L. et al (2011). Journal of Clinicial and Experimental Neuropsychology, 33, 101-111
Digit span assessment with traditional measure, the Two Error Maximal Lenght (TE_ML), and a new measure, the Maximum Length (ML)
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.
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: Inquisit build
computer.platform: the platform the script was run on
date, time, subject, group: date and time script was run with the current subject/groupnumber
blockcode, blocknum: the name and number of the current block
trialcode, trialnum: the name and number of the currently recorded trial
(Note: not all trials that are run might record data; by default data is collected unless /recorddata = false is set for a particular trial/block)
values.assesstype: 0 for Forward and 1 for Backward trials
list.digitsequences.currentvalue: the selected sequence
list.digitsequences.currentindex: the index of the current sequence
values.N: the number of digits presented in a trial
values.countTrials: counts the trials run in the current assessment
values.sequence: the digit sequence presented
values.correctSolution: the correct digit sequence
values.proposedSolution: the entered digit sequence
values.correct: 1 = proposed solution is correct; 0 = otherwise
values.con_errorcount: consecutive error count on a level
values.TE_ML: the TE_ML, it's -1 until it's set (and once it's set it it should not change anymore)
values.TE_TT: the TE_TT, it's -1 until it's set (and once it's set it should not change anymore)
values.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.
values.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)
script.startdate: date script was run
script.starttime: time script was started
script.subjectid: subject id number
script.groupid: group id number
script.elapsedtime: stores the time in ms it took to run the script
computer.platform: the platform the script was run on
completed: 0 = script was not completed; 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_values.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
see section Editable Instructions;
instructions are provided as separate html-pages. Changes to the instructions need to be made to the
html files directly.
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)