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											SIMPLE ATTENTIONAL BLINK 

SCRIPT INFO

Author: Katja Borchert, Ph.D. (katjab@millisecond.com) for Millisecond Software, LLC
Date: 11-04-2013
last updated:  08-15-2016 by K. Borchert (katjab@millisecond.com) for Millisecond Software, LLC

Copyright ©  08-15-2016 Millisecond Software


BACKGROUND INFO

											*Purpose*
This script implements a simple Attentional Blink design inspired by: 

Raymond, J.E.; Shapiro, K. L.; Arnell, K. M. (1992) Temporary suppression of visual processing in an RSVP task: 
An attentional blink? Journal of Experimental Psychology: Human Perception and Performance, Vol 18(3), 849-860.

and:

Folk, C.L, Leber, A.B., Egeth, H.E. (2002). Made you blink! Contingent attentional capture produces 
a spatial blink. Perception & Psychophysics, 64, 741-753.

Attentional Blink: Reduced Processing of a second target (T1) that follows in short succession of a first target (T1)

Differences between script and Raymond et al (1992):
1. script uses constant stream length (see Folk et al, 2002) whereas Raymond et al (1992) used variable stream length 
2. reduced number of T1 stream positions and a reduced number of T1-T2 lag positions
3. T2 Task: in Raymond et al (1992) T2 was an X that could either be present or active. In this script, T2 is an X or a Z.
4. screencolor and color of letters and targets differ from Raymond et al (1992)

											  *Task*
Participants see a stream of non-repeating 20 letters. One of these letters is a red. This is target T1. It appears at
predetermined positions (here: streampositions 5 or 10). Another letter might be an X or a Z. This is called the T2 stimulus. 
The T2 stimulus appears after the T1 stimulus in the stream at predetermined lags (here: lags 1 or 7). At the end of the sequence, 
participants have to recall the red letter (T1) and decide whether they saw an X or a Z.


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

(1) Raw data file: 'SimpleAttentionalBlink_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 
/random_lettercolor				true (default): the regular letters in the stream will be assigned random colors.
											       (with exception of parameters.T1_color/parameters.T2_color). See list.randomlettercolors for details
								false: the regular letters will be presented in the color specified under parameters.lettercolor

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) 
/T1_streamposition:				holds the current temporal streamposition of the T1 stimulus
/T2_lag:						holds the current T1-T2 lag (Note: lag = 1 => t2 is presented directly after t1)
/T2_streamposition:				holds the current temporal streamposition of the T2 stimulus
/T1_stim:						holds the name of the current T1 stimulus
/T2_stim:						holds the name of the current T2 stimulus

stimulusitem:					the presented stimuli in order of appearance
response:						the participant's response (T1 task: openended response; T2 task: scancode for X or Y)
correct:						the correctness of the response (1 = correct; 0 = error)
latency: 						the response latency (in ms)
/letter1-
/letter18:						store the 18 letters in the letter sequence (letters other than T1 and T2)

(2) Summary data file: 'SimpleAttentionalBlink_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)
/random_lettercolor				true: the regular letters in the stream will be assigned random colors.
											       (with exception of parameters.T1_color/parameters.T2_color). See list.randomlettercolors for details
								false: the regular letters will be presented in the color specified under parameters.lettercolor
/T1_meancorr_pos5lag1:			mean number of correct responses to T1 task with T1 pos = 5 and T2 lag = 1
/T1_meancorr_pos5lag7:			mean number of correct responses to T1 task with T1 pos = 5 and T2 lag = 7
/T1_meancorr_pos10lag1:			mean number of correct responses to T1 task with T1 pos = 10 and T2 lag = 1
/T1_meancorr_pos10lag7:			mean number of correct responses to T1 task with T1 pos = 10 and T2 lag = 7

/T2_meancorr_pos5lag1:			mean number of correct responses to T2 task with T1 pos = 5 and T2 lag = 1
/T2_meancorr_pos5lag7:			mean number of correct responses to T2 task with T1 pos = 5 and T2 lag = 7
/T2_meancorr_pos10lag1:			mean number of correct responses to T2 task with T1 pos = 10 and T2 lag = 1
/T2_meancorr_pos10lag7:			mean number of correct responses to T2 task with T1 pos = 10 and T2 lag = 7



EXPERIMENTAL SET-UP: 
- simple AB design with: 2 T1 streampositions x 2 T1-T2 lag positions x 2 T2 stimuli x 30 repetitions each = 240 trial sequences*
(repetitions in this script occur only if all possible 8 combinations have been run once)
	
	Practice Block
	- 12 practice trial sequences (same as test sequences but with error feedback)

	Test Block Set-Up:
	- 240 Trial Sequences
	- random selection of T1 streamposition/lag/T2 with equal distribution of the two T2 across the 4 conditions T1streampositions x t1-t2 lags
	- every 60 (default) trial sequences are followed by a rest trial
		Trial Sequence:
		- Fixation cross presentation for parameters.fixationduration (editable value)
		- A stream of 20* (default) white (or randomly colored) letters are presented: letters are randomly selected without replacement
		- one of the letters in the stream is red (default) => T1
		- one of the letters following the T1 is either an X or a Z => T2
		-> participants are asked to recall the T1 at the end of the stream
		-> participants are asked to press X if T2 = X or press Z if T2 = Z

		!!! Note: LETTER PRESENTATION TIME
		The letter presentation duration in this script is coded in terms of stimulusframes.
		On a monitor with a vertical refresh rate of 60Hz, one stimulusframe ~16.7ms.

		Each letter in this script is presented for 1 stimulusframe (~16.7ms on a 60Hz monitor)
		with a blank stimulus interval of 5 stimulusframes (~83.3ms on a 60Hz monitor)

STIMULI
Items can be edited under EDITABLE STIMULI; 
Text sizes can be edited under EDITABLE PARAMETERS

EDITABLE CODE:
check under EDITABLE CODE 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:

/restperiods:								ratio of trialsequences to rests (aka there is a rest trial following every
											60 trial sequences - default)

Duration variables:
/restduration:								duration of rest trial in ms (default: 60000ms)
/fixationduration:							duration of fixation cross in ms (default: 500ms)
/responsecue_duration:						duration of the response cue in ms (default: 500ms) <= not in original article
									
Letter/targets:
/stimulussize_letters:						height of the letters relative to screen height (default: 10%)
/random_lettercolor							true: the regular letters in the stream will be assigned random colors.
											       (with exception of parameters.T1_color/parameters.T2_color). See list.randomlettercolors for details
											false: the regular letters will be presented in the color specified under
											       parameters.lettercolor
/lettercolor:								specifies the regular letter color if parameters.random_lettercolor == false
/T1_color:									specifies the color of T1 (default: red)
/T1_color_label:							the word label for T1 color (default: "RED")
/T2_color:									specifies a particular color for T2 (if left blank = "" => T2 gets the same color as regular
											stream letters)

/responsekey_T2_1:							scancode of responsekey 1 (default: 45)
/responsekey_label_T2_1:					responsekey 1 label (default: 'X')			
/responsekey_T2_2:							scancode of responsekey 2 (default: 44)
/responsekey_label_T2_2:					responsekey 2 label (default: 'Z')	

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