Introduction
Inhibition Of Return (IOR) is a phenomenon first described by Michael Posner and Yoav Cohen in 1984.
People are slower in detecting relevant stimuli at positions that have been attended shortly before to view an uninformative cue (time between uninformative cue and target has to be at least 300 ms).
The effect is, absolutely speaking, relatively small. The response time difference between detecting relevant stimuli at locations that were cued before and locations that were not cued before is around 20 ms. The effect size depends strongly on the interval between cue and stimulus. At shorter times between cue and target, people respond faster to locations that were previously cued.
About this implementation
In this example, you need to respond to a green stimulus "GO". In each trial, you need to ignore the "X" stimulus. The "X" functions here as an uninformative cue. It is "uninformative" because the location of the "X" is randomly chosen. The time between the "cue" and the "target" stimulus in this example is 1 second. At the end, you will see how fast your responded in cued and uncued locations.
The demo takes less than 5 minutes to complete (100 trials).
Run the demo
Stimulus-response associations
Use the following keys for your response:
|
PsyToolkit code
Click to expand the PsyToolkit script code (part of zip file below)
# every line starting with # is comment
options
bitmapdir stimuli # the folder that contains the stimuli bitmaps
escape
# the following section defines the bitmaps. the default format for
# bitmaps is "png" if you use png files, you do not need to use the
# extension.
bitmaps
cuesignal # this refers to the file cuesignal.png
gosignal
fixpoint1 # small
fixpoint2 # medium
fixpoint3 # large
box
instruction
afterwords
mistakefeedback
fonts
arial 20
# the table section contains 4 rows, one for each of the four
# conditions the stuff in quatation marks is human readable
# information, the program doesn't really need it.
table iortable
"cueleft targetleft cued 0" -200 -200 1
"cueleft targetright uncued 1" -200 200 2
"cueright targetleft uncued 1" 200 -200 1
"cueright targetright cued 0" 200 200 2
# the task describes exactly one trial. On each each trial, one of the
# rows of the cue table is chosen at random
task iortask
table iortable
keys a l
delay 500 # time between trials
show bitmap fixpoint1
show bitmap box -200 0
show bitmap box 200 0
delay 75
show bitmap fixpoint2
delay 75
show bitmap fixpoint3
delay 75
clear 4 5
show bitmap fixpoint2
delay 75
clear 6
show bitmap fixpoint1
delay 200
show bitmap cuesignal @2 0 # now show the cue
delay 200
clear -1
delay 800
show bitmap gosignal @3 0 # show target (go) 700 ms later
readkey @4 1500
clear -1
if STATUS != CORRECT
show bitmap mistakefeedback 0 200
delay 2000
clear -1
fi
save @1 RT STATUS # this saves the data to an output file
block iorblock
bitmap instruction
wait_for_key
tasklist
iortask 100 # do the task 100 times
end
bitmap afterwords
wait_for_key
feedback
set &RTcued mean c5 ; prefix "Cued conditions:" ; select c6 == 1 && c4 == 0
set &RTuncued mean c5 ; prefix "Uncued conditions:" ; select c6 == 1 && c4 == 1
set &IOReffect expression &RTcued - &RTuncued
text 0 0 "Response time (ms)"
text 0 50 &RTcued ; prefix "Cued conditions: " ; postfix " ms"
text 0 100 &RTuncued ; prefix "Uncued conditions:" ; postfix " ms"
text 0 150 &IOReffect ; prefix "IOR effect (cued - uncued):" ; postfix " ms"
text 0 250 "Press space bar to continue"
end
Download
If you have a PsyToolkit account, you can upload the zipfile directly to your PsyToolkit account. Watch a video on how to do that. If you want to upload the zipfile into your PsyToolkit account, make sure the file is not automatically uncompressed (some browsers, especially Mac Safari, by default uncompress zip files). Read here how to easily deal with this. |
Data output file
In PsyToolkit, the data output file is simply a textfile. The save line of the PsyToolkit experiment script determines what is being saved in the data output file. Typically, for each experimental trial, you would have exactly one line in your text file, and each number/word on that line gives you the information you need for your data analysis, such as the condition, response speed, and whether an error was made. |
Meaning of the columns in the output datafile. You need this information for your data analysis.
Colum | Meaning |
---|---|
1 |
cue position (left or right) |
2 |
target position (left or right) |
3 |
cue validity (cued/valid, uncued/invalid) |
4 |
same as column 3, cued as a number 0=cued, 1=uncued |
5 |
Response time (milliseconds) |
6 |
Status (1=correct, 2=wrong, 3=timeout) |
Further reading
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Abrams, R. A., & Dobkin, R. S. (1994). The gap effect and inhibition of return: Interactive effects on eye movement latencies. Experimental Brain Research, 98, 483-487.
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Abrams, R. A., & Dobkin, R. S. (1994). Inhibition of return: Effects of attentional cuing on eye movement latencies. Journal of Experimental Psychology: Human Perception and Performance, 20, 467-477.
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Klein, R. M. (2000). Inhibition of return. Trends in Cognitive Sciences, 4, 138-146.
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Posner, M.I. & Cohen, Y.P.C. (1984). Components of visual ori- enting. In H. Bouma & D. Bouwhuis (Eds.), Attention and per- formance X: Control of language processes (pp. 531–556). London: Lawrence Erlbaum.
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Pratt, J., & Abrams, R. A. (1999). Inhibition of return in discrimination tasks. Journal of Experimental Psychology: Human Perception and Performance, 25, 229-242.