Return to the Missing Scan Task page
___________________________________________________________________________________________________________________	

											*Missing Scan Test*
___________________________________________________________________________________________________________________	

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 04-03-2019
last updated:  06-30-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 06-30-2020 Millisecond Software

___________________________________________________________________________________________________________________
BACKGROUND INFO 	
___________________________________________________________________________________________________________________	

This script implements a Missing Scan Test (MST) procedure based on the procedure described by Buschke (1963).
Disclaimer: the procedure implemented is a best guess effort by Millisecond Software.

In general the MST procedure presents lists of randomly ordered items (mostly numbers) of well known sets 
(Example: set 1-16) that leave out one set member (e.g. 5). Participants then have to name the missing set member. 

The MST procedure is believed to test item short term memory retention that is less subject to retrieval effects 
than recall/recognition tests. According to Bushke the MST method does not require retrieval 
by recall or recognition as it depends mainly on prior (well versed) knowledge of class membership. 
In order to correctly report the missing class member of such a well-known class, however, retention of all 
presented class members is still necessary and thus the MST can be used as a capacity measure for short term 
memory. 

Usually, the MST methodology uses lists of items that are greater in length than is used in digit span tests 
(e.g. N=13) and use items that are well-known such as lists of consecutive numbers. 

Reference

Buschke, H. (1963). Retention in Immediate Memory Estimated without Retrieval.
Science, New Series, Vol. 140, No. 3562 (Apr. 5, 1963), pp. 56-57
https://www.jstor.org/stable/1710736

___________________________________________________________________________________________________________________
TASK DESCRIPTION	
___________________________________________________________________________________________________________________	

This script runs an MST task and Digit Span (DS) task* (optional). Order of task is determined by 
selected groupnumber.
Both tasks are using the same stimuli lists which are generated at the beginning of each script run.
By default, only the MST task is set to be run (see editable parameters).

Participants are given a class of consecutive numbers of varying lengths (4, 6, 8, 10, 12, 14).
The classes are taken from the numbers 1-16.
Example class: '4, 5, 6, 7, 8, 9 '
Then participants hear a random order of these elements. However, one of the items is missing.
Example presentation: "seven", "four", "five", "eight", "nine"

MST: participants are asked to name the missing number (by default, the missing number is selected from a number dial)
DS: participants are asked to name all the numbers that were presented, order is not important 
(by default, numbers are selected from a number dial)

*the DS task is simplified: participants get the same stimuli lists as in the MST task and recalling
the order of the items is not important (see Buschke, 1963)

___________________________________________________________________________________________________________________	
DURATION 
___________________________________________________________________________________________________________________	
the default set-up of the script* takes appr. 25-30 minutes to complete

*by default, this script only runs the MST task. If the DS task is run duration will double.
___________________________________________________________________________________________________________________	
DATA FILE INFORMATION 
___________________________________________________________________________________________________________________		
The default data stored in the data files are:

(1) Raw data file: 'missingscantest_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. 
										
										
level:								the currently tested level (length of sequence) 
missingNumber:						the selected missing Number of the currently tested sequence (e.g. 6)
class:								the selected class (e.g. '5, 6, 7, 8')
startNumber:						the first class member
lastNumber:							the last class member
presentationClass:					the selected class in the randomly ordered presentation (e.g. 05080706)
presentedNumbers:					lists the presented numbers in order of presentation (missing number is not presented)

enteredResponse:					all the entered responses in the order entered (including those respones that might have been deleted)

finalResponse: 						the final response given for the current trial
									Note: for DS trials the final values.finalResponse contains the ordered sequence of entered numbers
									(thus it may not reflect the order in which the items were named)
									
correctResponse: 					the correct response for the current trial (Note: for DS trials it contains the ordered response)									

correct:							accuracy of response: 1 = correct response; 0 = otherwise

rt:									the cumulative response time (in ms) of all trials that collected a number until the submit button is pressed/'done'	
									measured from onset of first reponse collecting trial

mainly used for debugging:									
parameters.debugmode:				for data collection purposes this value should be 0 (if it's 1 participants will be able to see correct responses on the screen)									
sequenceLength:						stores the length of the sequence (should be equal to values.level)
values.theoreticalPresentedNumbers:	the theoretically presented numbers (should be equal to values.presentedNumbers)


(2) Summary data file: 'missingscantest_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)
									
									
MST:								retention span for the Missing Scan Test 

MST_propCorrect_level4:				stores the proportion correct responses for level 4 MST trials
MST_meancorrRT_level4:				stores the mean reaction time for level 4 MST trials (correct trials only)
(same for level6, level8, level10, level12, level14 trials)

DS:									retention span for the (simplified) Digit Span Test

DS_propCorrect_level4:				stores the proportion correct responses for level 4 DS trials
DS_meancorrRT_level4:				stores the mean reaction time for level 4 DS trials (correct trials only)
(same for level6, level8, level10, level12, level14 trials)								
							
							
* separate data files: to change to one data file for all participants (on Inquisit Lab only), go to section
"DATA" and follow further instructions

___________________________________________________________________________________________________________________	
EXPERIMENTAL SET-UP (best guess effort)
___________________________________________________________________________________________________________________	

This script is set up to run a Missing Scan Test (MST) and a Digit Span (DS) Assessment by default.
The order of the tasks is counterbalanced by groupnumber:
odd groupnumbers will run MST -> DS; even groupnumbers will run DS -> MST
(Note: parameters.runDSAssessment controls whether the DS Assessment is run)

Stimuli Preparation:
At the beginning of the script, the script generates all the stimuli that are used for the MST/DS task:
- the script generates stimuli for 90 trials: 15 trials for each of the 6 levels (4, 6, 8, 10, 12, 14) tested 
- the script randomly selects a level (4, 6, 8, 10, 12, 14) and randomly (without replacement)
selects the missing number for the current level (1-15) (Note: each level runs numbers 1-15 once as the missing number)
	Example: level 4, missing number 5

- an algorithm randomly selects a suitable class/sequence for the selected level and selected missing number
and randomizes the order of the numbers for presentation purposes.
Note: the missing number is never 'a limiting number of the class' (Buschke, 1963) which 
Millisecond Software interpreted to be the highest number of the class.
	Example: class generated: '3, 4, 5, 6' => presentation class: '04050306' (the missing number '05' will not be presented)

- the information is then added to several level specific lists 
(e.g. list.level4_class, list.level4_missingNumber, list.level4_presentationNumbers), so that MST and DS assessment
run the very same stimuli for each level

Response Format:
By default, the stimuli are presented orally at 1 number per second and the response is collected in 'written' format
(the numbers are selected from a number dial).
Note: parameters.responseFormat can be set to collect oral responses.

MST Task:
(1) Demo: a minimum of one demo trial (level=3) is run to demonstrate the setup of the MST task
(participants can decide whether they want to run additional demo trials)
- the script randomly selects the missing number and generates a suitable class and random presentation order
- the class is announced to participants (start button press starts the random sequence delivery)
- the numbers are presented orally at 1 number per second
- after a default delay of 0ms (editable parameter) the response is collected either in 'written'
format (number selection from a number dial; default) or in verbal format (Response: missing number only)
- participants receive feedback during the demo

(2) Test:
- the script randomly selects a level without replacement (levels: 4, 6, 8, 10, 12, 14; each tested 15 times)
- the script randomly selects the missing number of the level as well as the generated class and
random presentation order
- the class is announced to participants (start button press starts the random sequence delivery)
- the numbers are presented orally at 1 number per second in random order
- after a default delay of 0ms (editable parameter) the response is collected either in 'written'
format (number selection from a number dial; default) or in verbal format (Response: missing number only)
- participants do not receive feedback during the test
- after an intertrial interval (default: 500ms; editable parameters), the next class is presented


DS Task:
(1) Demo: a minimum of one demo trial (level=3) is run to demonstrate the setup of the MST task
(participants can decide whether they want to run additional demo trials)
- the script randomly selects the missing number and generates a suitable class and random presentation order
- the class is announced to participants (start button press starts the random sequence delivery)
- the numbers are presented orally at 1 number per second
- after a default delay of 0ms (editable parameter) the response is collected either in 'written'
format (number selection from a number dial; default) or in verbal format (Response: ALL the numbers presented; order is irrelevant)
- participants receive feedback during the demo

(2) Test:
- the script randomly selects a level without replacement (levels: 4, 6, 8, 10, 12, 14; each tested 15 times)
- the script randomly selects the missing number of the level as well as the generated class and
random presentation order
- the class is announced to participants (start button press starts the random sequence delivery)
- the numbers are presented orally at 1 number per second
- after a default delay of 0ms (editable parameter) the response is collected either in 'written'
format (number selection from a number dial; default) or in verbal format (Response: ALL the numbers presented; order is irrelevant)
- participants do not receive feedback during the test
- after an intertrial interval (default: 500ms; editable parameters), the next class is presented

Span Assessment:
The assessment of the MST and the digit span was inspired by the method recommended by Woodworth and Schlosberg (1954):
The script started with a base value of 2:
MST: 2 + 2*x/15 (level4) + 2*x/15 (level6) + 3*x/15 (8) + 2*x/15 (10) + 2*x/15 (12) + 2*x/15 (14)
DS: 2 + 2*x/15 (level4) + 2*x/15 (level6) + 3*x/15 (8) + 2*x/15 (10) + 2*x/15 (12) + 2*x/15 (14)

=> the span range possible with this algorithm: 2-14


Description of experimental setup in Buschke (1963):
"The test items were the numbers from one to sixteen. 
Series containing 4, 6, 8, 10, 12, or 14 randomly ordered numbers were prepared so that in the 15 series 
for each number of items the missing number was randomly 1 through 15. 
This was achieved by using appropriate segments of the sequence one to sixteen as the classes 
from which one number was missing. The missing number was never a limiting number of the class. 

Before both digit-span and missing-scan tests the subjects were told the class or sequential 
series of numbers to which the numbers presented belonged."

___________________________________________________________________________________________________________________
STIMULI
___________________________________________________________________________________________________________________
Numbers 1-16, presented orally (using voiceover feature of text elements)

__________________________________________________________________________________________________________________	
INSTRUCTIONS 
___________________________________________________________________________________________________________________	
provided by Millisecond Software - can be edited under section Editable Instructions

___________________________________________________________________________________________________________________	
EDITABLE CODE 
___________________________________________________________________________________________________________________	
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: