Return to the Inhibition of Return (IOR) page

Script Author: Katja Borchert, Ph.D. ( for Millisecond Software, LLC
Date: 04-29-2013
last updated: 01-14-2016 by K.Borchert ( for Millisecond Software LLC

Copyright © 01-14-2016 Millisecond Software


This script implements the Inhibition of Return procedure as described in:

Abroms, B.D. & Fillmore, M.T. (2004). Alcohol-Induced Impairment of Inhibitory Mechanisms Involved in
Visual Search. Experimental and Clinical Psychopharmacology, 12, 243–250.

Millisecond Software thanks Dr.Fillmore for his generous support in developing this script!

Participants are asked to press a key when they see a white star (target) in a box either to the left or
the right of a center box. Before the target is presented, either the left or the right box is briefly
"lit" (=cue) to shift attention towards cued location  and is then followed by a briefly "lit" center square 
to shift attention back to the center location.

After a certain timeframe (min. 300ms) btw. cue and target, participants tend to be SLOWER to attend to the 
cued location (aka detect the star) => Inhibition of Return											  

The default data stored in the data files are:

(1) Raw data file: 'InhibitionOfReturn_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) 
/condition:						different, same, catch
/currentSOA:					the SOA of the current trial

/targetduration:				max duration of target trials (max time that star is presented, default: 1000ms)
response:						the participant's response
correct:						the correctness of the response (1 = correct; 0 = incorrect)
latency: 						the response latency (in ms)

Summary Variables:
/countcorrect_same:				counts the correct responses for same condition
/countcorrect_diff:				counts the correct responses for different condition
/sumrt_same:					sums up the correct latencies for same condition
/sumrt_diff:					sums up the correct latencies for different condition
/countcorr_catch:				counts the correct responses for catch trials
/counterror_catch:				counts the error responses for catch trials
/sumrt_catch:					sums up the error latencies for catch trials

(2) Summary data file: 'InhibitionOfReturn_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 (script was prematurely aborted); 1 = script was completed (all conditions run)

+ mean reaction times for same, different (only correct responses) and catch trial (error responses)

a) Design:  	2 cue-target associations (target in same box as cue, target in opposite box as cue) x 
				5 SOAs (stimulus onset asynchronies; time between onset of cue and onset of target)

b) Experimental Block: 
- presents 200 trials each for same/different condition (=> 40 per SOA)
- presents 100 catch trials (no target presentations, the target trials ends after 1000ms)
- after 250 trials a rest trial is presented for 60s (default); 10s before rest trial is over
a beep alerts participants that rest is coming to an end.

c) Practice Block:
- runs 30 trials

d) Trial Sequence:
cue-presentation trials:
-> present fixation cross for 500ms (0-500ms)
-> then present the slightly gray boxes for 500ms (500-1000ms)
-> then "light" up the left (or right) box for 20ms (1000-1020ms)  <= SOA starts at 1000ms
-> present the original slightly gray boxes for 10ms before (1020-1030ms)
-> lightening the centersquare for 20ms (1030-1050) 
-> present the original slightly gray boxes for values.soa_remaining (=SOA-50ms)

target-presentation trials:
-> present the target for max 1000ms
trial either ends automatically after 1000ms or if participant responds

*catch trials are used to catch "anticipatory" responses/responders
as they do not present a target but allow responses from the time the cue is presented (regular
cue presentation trials do not) 
=> in the original IOR procedure (Abroms & Fillmore, 2004) catch trials worked the exact same way experimental trials worked
without targets: that is they recorded responses only after the randomly sampled SOA was over and a target could appear.
This script records responses during catch trials right after the cue disappears and may therefore be slightly more sensitive to
catching anticipatory responses as anticipatory responses during long SOAs wouldn't necessarily be recorded in the original
*To change any SOAS go to EDITABLE CODE -> Editable Lists

Abroms & Fillmore (2004) report specific cm dimensions of their stimuli. This script codes
the dimensions of the stimuli in % of the screen height.
Go to EDITABLE CODE -> Editable Values and change the values for a custom experiment
(Abroms & Fillmore, 2004:
- squares: height 4cm
- distance: peripheral boxes-center box: 7cm
- star: 2cm diameter)

Instructions are not originals. Customize under EDITABLE CODE -> Editable Instructions

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:

Stimuli Dimensions/Placements
/squareheight:									the height of the square in %screenheight (default: 20%)
/fontheight:									the height of the fontheight in %screenheight (default: 10%)
/leftsquare_x:									x-coordinate of left square (default: 25%)
/rightsquare_x:									x-coordinate of the right square (default: 75%)

/responsekey:									scancode of the response key (default: 57)
/responsekeylabel:								corresponding label of responsekey (default: )

/targetduration:								max duration of target trials (max time that star is presented, default: 1000ms)
/ITI:											intertrialinterval (default: 500ms)
/restduration:									the duration of a rest trial that is presented after 250 trials (default: 60000ms)

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