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										VISUAL SEARCH
										(behavioral data only)
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Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 06-19-2017
last updated:  03-12-2020 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Script Copyright © 03-12-2020 Millisecond Software

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BACKGROUND INFO 	
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This script implements a basic visual search paradigm based on:

Motter,B.C., & Simoni, D.A. (2008). Changes in the functional visual field during search with and without
eye movements. Vision Research 48 (2008) 2382–2393.

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TASK DESCRIPTION	
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Participants are asked to check letter arrays of green and red L's and T's (in 6 different spatial rotations)
of varying array sizes (6, 12, 24, 48) for a target letter. 
The target letter shares one feature with each distractor letter ("conjunction style search array"). 
For example, if the target letter is a red L, the distractor letters are red T's and green L's. 
Half the arrays contain the target.

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DURATION 
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the default set-up of the script takes appr. 25 minutes to complete
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DATA FILE INFORMATION 
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The default data stored in the data files are:

(1) Raw data file: 'visualsearch_letters_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
script.sessionid:					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 such as feedback trials. Thus, trialnum 
										may not reflect the number of main trials run per block.
										
values.arraySize:					stores the number of stims presented (6, 12, 24, 48)									
values.targetPresent:				1 = target presented in array; 0 = otherwise	
picture.target.hposition:			the horizontal screen position (in % of canvas width)
picture.target.vposition:			the vertical screen position (in % of canvas height)

expressions.targetDistance:			calculates the distance (in %) from the target stim to the center (fixation cross)
									relative to the screen canvas (portion of monitor used for stimulus display)
									(only valid for 'Target Present' trials)
									-> the value can be converted to absolute measurements if the dimensions of the monitor are known
									(also needed: expressions.canvasRatio)	
									
expressions.canvasRatio:			calculates the ratio of canvas (=the part of the screen that is used by the script) height to height 
									of monitor(in %)	

values.currentTarget:				stores the itemnumber of the current target item cue								
response:							the participant's response (scancode of response button: 18(E); 23(I))
Response:							translates scancode of response button into response: 'yes' vs. 'no
values.responseCategory:			accuracy of response: 1 = correct response; 0 = otherwise
latency: 							the response latency (in ms); measured from: onset of stims (after presentation of cue)


(2) Summary data file: 'visualsearch_letters_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)

expressions.ACCoverall:				overall proportion correct (across all test trials)
expressions.meanRT:					mean latency (in ms) across all correct test trials

expressions.ACCtargetPresent_6:		proportion correct of trials with 6 stimuli where the target is present
expressions.RTtargetPresent_6:		mean correct latency (in ms) of trials with 6 stimuli where the target is present
expressions.ACCtargetAbsent_6:		proportion correct of trials with 6 stimuli where the target is absent
expressions.RTtargetAbsent_6:		mean correct latency (in ms) of trials with 6 stimuli where the target is absent

expressions.ACCtargetPresent_12:	proportion correct of trials with 12 stimuli where the target is present
expressions.RTtargetPresent_612:	mean correct latency (in ms) of trials with 12 stimuli where the target is present
expressions.ACCtargetAbsent_12:		proportion correct of trials with 12 stimuli where the target is absent
expressions.RTtargetAbsent_12:		mean correct latency (in ms) of trials with 12 stimuli where the target is absent

expressions.ACCtargetPresent_24:	proportion correct of trials with 24 stimuli where the target is present
expressions.RTtargetPresent_24:		mean correct latency (in ms) of trials with 24 stimuli where the target is present
expressions.ACCtargetAbsent_24:		proportion correct of trials with 24 stimuli where the target is absent
expressions.RTtargetAbsent_24:		mean correct latency (in ms) of trials with 24 stimuli where the target is absent

expressions.ACCtargetPresent_48:	proportion correct of trials with 48 stimuli where the target is present
expressions.RTtargetPresent_48:		mean correct latency (in ms) of trials with 48 stimul]i where the target is present
expressions.ACCtargetAbsent_48:		proportion correct of trials with 48 stimuli where the target is absent
expressions.RTtargetAbsent_48:		mean correct latency (in ms) of trials with 48 stimuli where the target is absent


* separate data files: to change to one data file for all participants (on Inquisit Lab only), go to section
"DATA" and follow further instructions

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EXPERIMENTAL SET-UP 
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Practice: default
- 24 practice trials (6 per target category, e.g. 'green L', order is randomized)
- each possible target is used once per target category - random selection)
- 2 different array sizes per target category (4 stims vs. 16 stims), random selection
- half the trials (12) have the target present (order of 'target present' vs. 'target absent' randomized)
- provides performance feedback


Test: default 
2 target colors (green vs. red) x 2 target letters (L vs. T) x 4 array sizes (6, 12, 24, 48) x 2 target condition (present vs. absent) 
x 6 reps = 192 trials, 
tested in a full, mixed design

- the 4 target categories (color x letter) are selected in random order
- in each of the 4 target conditions (color x letter, e.g. 'green L'): 
	- equal frequency of the 4 possible array sizes (array size is randomly determined)
	- half the targets are present, half the targets are absent (randomly selected)
		=> balanced across the 4 different set sizes (6 targets present/6 targets absent for each of the 4 set sizes)
		Note: Motter & Simoni (2008) ran sessions of 240 trials.
	
- Target Selection:
	- The target stimulus is selected randomly from the 6 possible rotations (see under STIMULI) for the given target condition)
	- each rotation is selected equally often 
	=> each target rotation is run 8 times per target condition
	
- Distractor Selection:
		- half the distractors are selected from the opposite color (but same letter)
			-> the appropriate item numbers are selected randomly without replacement (repetitions are possible, once all 6 possible stims were selected)
		- the remaining distractors are selected from the same color (but different letter)
			-> the appropriate item numbers are selected randomly without replacement (repetitions are possible, once all 6 possible stims were selected)

- Stim Locations:
	- 48 possible stim locations (7x7 matrix, with fixation cross in the center)
	- stim locations are randomly (without replacement) assigned to each of the stims (including target)
	- stim locations reset before each new trial


Canvas:
By default, the canvas (=part of the screen used by this script) is the biggest square (width = height) that can be
established on the current monitor. The canvas can be further manipulated by explicitly forcing
a specific canvas size and/or by forcing a specific windowsize (see section DEFAULTS for more info)	
	

Trial Sequence:
Fixation Cross (until Spacebar press) -> Cue (default: 1000ms)->Array (max: 7000ms)
	
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STIMULI
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provided by Millisecond Software - can be edited under section Editable Stimuli

Note:
each target category (green L, red L, green T, red T) can be represented by 1 of 6 orientations:
the letter was rotated 6 times by increments of 60deg

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INSTRUCTIONS 
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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).
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EDITABLE CODE 
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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:

/cueDuration:							duration (in ms) of cue (default: 1000ms)
/responseWindow:						duration (in ms) of response window (default: 7000ms)
/spacebarReminder:						the delay (in ms) after which a spacebar-response reminder is presented (default: 2000ms)
/feedbackDuration:						duration  (in ms) of feedback duration (default: 2000ms)
/readyDuration:							duration (in ms) of get-ready trial (default: 3000ms)
/picSize:								proportional sizing of images in percentage of canvas height (default: 10%)
/fixationSize:							proportional sizing of fixation cross in percentage of canvas height (default: 10%)

Response Keys:
/yesKey:							the yes-key scancode (default: E); the left response key
/noKey:							the no-key scancode (default: I); the right response key