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						Immediate & Delayed Memory Task (IMT/DMT) - Testing Session
SCRIPT INFO

Script Author: David Nitz (dave@millisecond.com) for Millisecond Software, LLC
last updated: 01-14-2016 by K.Borchert (katjab@millisecond.com) for Millisecond Software LLC

Copyright © 01-14-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
	This script implements a practice session for the Immediate & Delayed Memory Task (IMT/DMT) described in:

	Dougherty, D.M., Marsh, D.M., and Mathias, C.W. (2002). Immediate and Delayed Memory Tasks:  A computerized measure 
	of memory, attention, and impulsivity. Behavior Research Methods, Instruments, and Computers, 34, 391-398.

	
											  *Task*
Participants view a steady stream of 5-digit (default) numbers and are asked to click the Mouse button if the current
target number is identical to the one before it.
2 slightly different conditions:
A) Delayed: the target numbers are followed by three distractor numbers. The distractor numbers are always the same
number (12345).
B) Immediate: target numbers follow target numbers immediately. No distractors are used.



DATA FILE INFORMATION: 
The default data stored in the data files are:

(1) Raw data file: 'IMTDMT_test_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) 
stimulusitem:					the presented stimuli in order of trial presentation
response:						the participant's response
correct:						the correctness of the response (1 = correct; 0 = incorrect)
latency: 						the response latency (in ms)

(2) Summary data file: 'IMTDMT_test_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:				time it took to run script (in ms)
computer.platform:				the platform the script was run on
/completed:						0 = script was not completed (prematurely aborted); 1 = script was completed (all conditions run)
ndigits							Number of digits for stimuli. Valid range is 2-7. Default is 5.
									Default is "1234567". The distractor string will automatically be cropped to the correct length as
									specified by ndigits.

imt_blockcount					Number of IMT blocks run.
imt_totalcorrectdetections		Total number of correct detections across all IMT blocks.
imt_n_targettrials_total		Total number of target trials across all IMT blocks.
imt_correctdetections_pct_total	Computes the percentage of correct detections across all IMT blocks.
imt_totalcommissionerrors		Total number of commission errors across all IMT blocks.
imt_n_catchtrials_total			Total number of catch trials across all IMT blocks.
imt_commissionerrors_pct_total	Computes the percentage of commission errors across all IMT blocks.
imt_totalfillererrors			Total number of filler errors across all IMT blocks.
imt_n_fillertrials_total		Total number of filler trials across all IMT blocks.
imt_fillererrors_pct_total		Computes the percentage of filler errors across all IMT blocks.

imt_meantargetlatency_total		Computes the mean RT for responses to target stimuli across all IMT blocks.
imt_meancatchlatency_total		Computes the mean RT for responses to catch stimuli across all IMT blocks.

imt_hr							Computes the hit-rate across all IMT blocks.
imt_fr							Computes the false-alarm-rate across all IMT blocks.
imt_dprime						Computes d' for the IMT (parametric measure of discriminability).
imt_beta						Computes ß (beta) for the IMT (parametric measure of bias).
imt_aprime						Computes A' for the IMT ("nonparametric" measure of discriminability).
imt_bd							Computeds B''d for the IMT ("nonparametric" measure of bias; cf. Donaldson, 1992).


dmt_blockcount					Number of DMT blocks run.

dmt_totalcorrectdetections		Total number of correct detections across all DMT blocks.
dmt_n_targettrials_total		Total number of target trials across all DMT blocks.
dmt_correctdetections_pct_total	Computes the percentage of correct detections across all DMT blocks.
dmt_totalcommissionerrors		Total number of commission errors across all DMT blocks.
dmt_n_catchtrials_total			Total number of catch trials across all DMT blocks.
dmt_commissionerrors_pct_total	Computes the percentage of commission errors across all DMT blocks.
dmt_totalfillererrors			Total number of filler errors across all DMT blocks.
dmt_n_fillertrials_total		Total number of filler trials across all DMT blocks.
dmt_fillererrors_pct_total		Computes the percentage of filler errors across all DMT blocks.

dmt_meantargetlatency_total		Computes the mean RT for responses to target stimuli across all DMT blocks.
dmt_meancatchlatency_total		Computes the mean RT for responses to catch stimuli across all DMT blocks.

dmt_hr							Computes the hit-rate across all DMT blocks.
dmt_fr							Computes the false-alarm-rate across all DMT blocks.
dmt_dprime						Computes d' for the DMT (parametric measure of discriminability).
dmt_beta						Computes ß (beta) for the DMT (parametric measure of bias).
dmt_aprime						Computes A' for the DMT ("nonparametric" measure of discriminability).
dmt_bd							Computeds B''d for the DMT ("nonparametric" measure of bias; cf. Donaldson, 1992).

tasktype						1 = Run IMT only
									2 = Run DMT only
									3 = Run IMT -> DMT alternatingly
									4 = Run DMT -> IMT alternatingly
									Default is 3.
nblockspertask					Number of blocks per task. I.e., with tasktype=3 and nblockspertask=2, there will be 2 IMT blocks and
									2 DMT blocks in alternating order.
									Defaults: 
									For tasktype=1 and tasktype=2, nblockspertask should be set to 4.
									For tasktype=3 and tasktype=4, nblockspertask should be set to 2.

targetprobability				Default is 33.
catchprobability				Default is 33.
fillerprobability				Default is 34 (100-targetprobability-catchprobability)
									target-, catch- and fillerprobability *must* add up to 100!

									!!! IMPORTANT NOTICE !!!				
									* The above probabilities only apply to individual trials. 
									* They *do not* represent presentation probabilities across a session!
									* This is an important consideration when adjusting target and catch probabilities 
									* because a filler stimulus always follows a target or catch stimulus to prevent 
									* successive target or catch trials. 
									* Additionally, the first stimulus in a testing block will always be a novel filler stimulus. 
									* As a consequence, the actual percentage of trials for each stimulus type across an 
									* entire session can be expected to be approx. *half* of the respective probability value 
									* specified.
									* If needed, exact (empirical) probabilities for a given may be calculated based on the 
									* recorded (raw) data.
distractor						Type of distractor. Valid options are "1234567" and "0000000".
stimulusduration				Display duration of digit stimulus. Default is 500ms.
blackoutduration				Blackout duration after stimulus display. Default is 500ms.
blockduration					Duration of a single task block in ms. Default is 300000
restduration					Duration of rest period between task blocks in ms. Recommended values range between 15000 and 30000.
									Restduration can be set to 0 to run blocks without any breaks between them.
									Default is 30000ms

Additional Note: In Inquisit Lab, a screenshot can be saved any time a participant is presented a performance summary for the current block.	
To do so, go to trial.dmtsummarytrial/trial.imtsummarytrial/									
									
																		
EXPERIMENTAL SET-UP
Experimenter can select via parameters.tasktype which conditions (and in which order) participant runs through
the task(s)
1 => only IMT task (for practice: 2 repetitions)
2 => only DMT task (for practice: 2 repetitions)
3 => IMT task -> DMT task (for practice: once per task)
4 => DMT task -> IMT task (for practice: once per task)


STIMULI
target numbers (identical repeats): exact repeat of the last presented 5-digit number
catch numbers (similar numbers): 5-digit numbers (default) that differ by only 1 digit from the previous number (and are not equal to distractor items)
filler numbers (different numbers): randomly generated 5-digit numbers that differ in at least 2 digits from the previous number (and are not equal to distractor items)
Numbers are presented black on white. Size can be set via parameters.stimsize

INSTRUCTIONS
This script implements a testing session for the IMTDMT task. Instructions are not included (instructions are included in IMTDMT_practice.iqx).

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:

	stimsize						Size of digit stimuli in canvas height proportion; Adjust to suit your display size / resolution.
									Dougherty et al. recommend a height of approx. 33 mm for all (digit)
									stimuli.
	
	targetprobability				Default is 60.
	catchprobability				Default is 0.
	fillerprobability				Default is 40 (100-targetprobability-catchprobability)
									target-, catch- and fillerprobability *must* add up to 100!

									!!! IMPORTANT NOTICE !!!				
									* The above probabilities only apply to individual trials. 
									* They *do not* represent presentation probabilities across a session!
									* This is an important consideration when adjusting target and catch probabilities 
									* because a filler stimulus always follows a target or catch stimulus to prevent 
									* successive target or catch trials. 
									* Additionally, the first stimulus in a testing block will always be a novel filler stimulus. 
									* As a consequence, the actual percentage of trials for each stimulus type across an 
									* entire session can be expected to be approx. *half* of the respective probability value 
									* specified.
									* If needed, exact (empirical) probabilities for a given may be calculated based on the 
									* recorded (raw) data.

	ndigits							Number of digits for stimuli. Valid range is 2-7. Default is 5.
	distractor						Type of distractor. Valid options are "1234567" and "0000000".
									Default is "1234567". The distractor string will automatically be cropped to the correct length as
									specified by ndigits.
	blockduration					Duration of a single task block in ms. Default is 300000
	restduration					Duration of rest period between task blocks in ms. Recommended values range between 15000 and 30000.
									Restduration can be set to 0 to run blocks without any breaks between them.
									Default is 30000ms
	stimulusduration				Display duration of digit stimulus. Default is 500ms.
	blackoutduration				Blackout duration after stimulus display. Default is 500ms.
	tasktype						1 = Run IMT only
									2 = Run DMT only
									3 = Run IMT -> DMT alternatingly
									4 = Run DMT -> IMT alternatingly
									Default is 3.
	nblockspertask					Number of blocks per task. I.e., with tasktype=3 and nblockspertask=2, there will be 2 IMT blocks and
									2 DMT blocks in alternating order.
									Defaults: 
									For tasktype=1 and tasktype=2, nblockspertask should be set to 4.
									For tasktype=3 and tasktype=4, nblockspertask should be set to 2.

	!!! THESE VARIABLES CAN BE EDITED IN THIS SCRIPT BUT ARE FIXED IN THE ORIGINAL IMTDMT PROGRAM.
	minlatency:						the minimum latency that is accepted for a true response (default: 100ms)
	dmt_ndistractors:				number of consecutive distractor trials (default: 3) 
	minhdist:						minimum number of digits that need to differ between a new filler stimulus and a previous stimulus (default: 2)

	Debugging Parameter:
	showdebuginfo:					1 = displays red debugging info on the screen; 0 = debugging info cannot be seen


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