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								Mackworth Clock Vigilance Test
SCRIPT INFO

Script Author: Jeffrey Q. Ouyang (qijia.ouyang@gmail.com)
Date: 08-08-2011
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 the Mackworth Clock Vigilance Test as described in:

-Ann M.W. et al. 2001. Developing measures of fatigue using an alcohol comparison to validate 
 the effects of fatigue on performance. Accident Analysis and Prevention 33, 313-326.
-Mats G. et al. 1994. Relations Between Perfromance and Subjective Ratings of Sleepiness 
 During a Night Awake. Sleep 17, American Sleep Disorders Association and Sleep Research
 Society, 236-241. 
-Kenneth L.L. et al. 2000. The Macworth Clock Test: A Computerized Version, The Journal of 
Psychology, 134:2, 153-161

The Mackworth Clock Vigilance Test measures a subject's ability to sustain attention in the face of monotonous 
stimulation. 

											  *Task*
Participants watch a red dot jump from one circle position to next position (24) in a clockwise fashion at 
constant speed. Occasionally, the red dot skips a position. Participants are asked to press the Spacebar
whenever they notice such a skipped event.


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

(1) Raw data file: 'MackworthClock_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) 
stimulusitem:					the presented stimuli in order of trial presentation
response:						the participant's response
latency: 						the response latency (in ms)

values.hit:						1 = hit (spacebar pressed after skipped event); 0 = no hit 
values.miss:					1 = miss (spacebar not pressed after skipped event); 0 = no miss
values.false_alarm:				1 = False Alarm (spacebar pressed after a non-skipped event); 0 = no FA
				
values.total_hits:				counts all hits during test
values.total_misses:			counts all misses during test
values.total_falsealarms:		counts all false alarms during test
values.skip_count:				counts the number of skipped events during test

(2) Summary data file: 'MackworthClock_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)
values.total_hits:				counts all hits during test
values.total_misses:			counts all misses during test
values.total_falsealarms:		counts all false alarms during test
values.skip_count:				counts the number of skipped events during test
response_window_duration: 		the max time in ms that a participant can respond after a signal (skip) event 
/Mean_HitRT:					stores the mean Hit latency (in ms)
/STD_HitRT:        			    stores the standard deviation of all Hit latencies
/Median_HitRT:					stores the median Hit latency (in ms)



EXPERIMENTAL SET-UP:

Test Procedures: 
1. A circle, with 24 equally spaced "slots" (as represented by the empty space between 
two "+" marks), is presented on the computer screen.
2. A red dot starts from the 12'o clock position and flashes in turn in each "slot". 
2a.The dot stays visible for 0.65 sec and so there is an interval of 0.65 sec between each flash.
3. The signal event is when the dot skips a position. 
3a.Total number of signal events is user-definable.
3b.The signal events are "spread out" evenly around the average event intervals with pseudorandom
     components added in (rand(-10,10)).
3c.The subject identifies this event by hitting the space bar (or other user-definable key).
4. The entire test lasts up to a pre-defined amount of time.
	
INSTRUCTIONS
check 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:

User-definable Macworth clock test parameters: 
total_skip_events: 					Total number of signal (skip) events. 
total_runtime:      				Total amount of time in ms the Macworth clock test will run. 
norm_interval:    					Interval between regular dot "flashes".    (in ms, recommended: 500ms - 800ms, default: 650ms)
skip_interval:     					Flash Interval when there's a skip event. (in ms, recommended: 500ms - 800ms, default: 650ms) 
response_window_duration: 			the max time in ms that a participant can respond after a signal (skip) event 

*Note: If possible, skip events will be randomly distributed such that the duration before the next event 
is at least as long as the specified response window. This may not be possible, however, if relative large number of
events are specified for a relative short task time, or if the response window is too long.

Also defines the coordinates for boundary marks, flashing positions of red dot
and various internal system variables. 

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