Posner spatial cueing task demonstration by Ondrej Havlicek is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Based on a work at http://www.tandfonline.com/doi/abs/10.1080/00335558008248231.
As mentioned in the related blog post, this is an online demonstration of the famous experiment in cognitive psychology on covert visual attention by Michael Posner and colleagues. It is implemented as a Java applet and the blog post discusses how to resolve possible security warnings to make it run (the app does not have a digital signature). If you have any comments, please use the comment field under that post. Below you can find more information on how to use it, what to try, as well as the whole source code.
Quick start:
The applet requires Java 5 or higher. Java must be enabled in your browser settings. Mac users must have Mac OS X 10.4 or higher. You may obtain the latest Java from Oracle's Java site.
powered by NetLogo
view/download model file: posner.nlogo
Posner’s spatial cueing task is a classic experiment in cognitive psychology. It shows how spatial cues (central or peripheral) shift covert visual attention, resulting in better performance in case of a valid cue (points to where the target will actually appear) than for invalid cues (points in the wrong direction). Trials without a cue can serve as a control (neutral) condition. For more information, see e.g. Wikipedia , APA website about this task, or some paper on this task by Michael Posner (see below).
Of course, this implementation is not meant for real testing purposes but mainly for education. Namely, the timing of events is highly imprecise.
Loop of infinite series of trials. Target boxes are displayed all the time. At the beginning of a trial a fixation cross appears. Subjects must fixate their eyes on this cross. After a short period of time* a cue can appear. It can be either valid or invalid with respect to the coming target, or absent. After another short period of time, called the stimulus onset asynchrony (SOA), the actual target appears in one of the two boxes. In this version of the experiment the subject must press either the left key or the right key according to where the target is, as fast as possible. A feedback (smily or sad face) will be given after each response.
*Based on the settings.
First, adjust the speed of the experiment using the slider on top of the main window, so that 1000 ticks correspond roughly to 1 second in real time. Use the button Start to test this.
Then you can prepare a new experiment using the button Setup. Use the SOA slider to set the duration between the presentation of the cue and of the target. Use the drop-down list to choose between a central or a peripheral cue. Use the sliders below to choose the ratio of trials having a certain cue validity.
You then start or pause the experiment with the Start button.
Use your keyboard to respond to stimuli. Press A if the target is in the left box and S if it is in the right box.
You should do a few dozens of trials so that your average results stabilize over time and are accurate enough.
THe usual result is that reaction times are fastest for valid trials than for neutral trials and the invalid trials are the slowest. This depends on the SOA, trial type ratio and on the cue type (central, peripheral, or symbolic). What results do you get if you experiment with these different settings?
Try to experiment with all the possible settings of SOA, cue type and trial type ratios. For instance, try to increase the ratio of valid trials to possibly observe bigger effects. E.g., if you use the symbolic cue, what is the difference between using a ratio of valid:invalid trials = 1:1 and using a ration 4:1? Do the results change as a result of prolonged experience?
Check the psychological literature on Posner-type paradigms…
One could e.g. add a switch that would turn the neutral cue on or off. Without the neutral cue, the subject will have no arousing/target-onset predicting stimulus, which could influence performance on neutral trials.
An interesting feature of this model is that it is not actually a model or a simulation but an experiment dependent on the input from a person. There is a loop of events triggered by the number of ticks that have passed (see the code).
I am not aware of any similar model.
Created by Ondrej Havlicek, 2014, ohavlicek [ a t ] gmail.com, www.ondrejhavlicek.com
Based on the work of Michael Posner and others.
Posner, M. I. (1980). Orienting of attention. The Quarterly journal of experimental psychology 32 (1): 3-25. doi:10.1080/00335558008248231. PMID 7367577
Posner spatial cueing task demonstration by Ondrej Havlicek is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Based on a work at http://www.tandfonline.com/doi/abs/10.1080/00335558008248231.
breed [people person]
breed [targets target]
breed [cues cue]
breed [fixations fixation]
breed [feedbacks feedback]
breed [csymbols csymbol]
breed [tsymbols tsymbol]
cues-own [orientation]
globals
[
speed
triallength
validlist
invalidlist
neutrallist
vcorrect
verrors
icorrect
ierrors
ncorrect
nerrors
vrate
irate
nrate
vmeanrt
imeanrt
nmeanrt
rtime
onsettick
canrespond?
targetpos
trialtype
sumratio
dice
]
to reset
__clear-all-and-reset-ticks
set canrespond? false
set targetpos 0
set trialtype 1
set validlist []
set invalidlist []
set neutrallist []
set vcorrect 0
set verrors 0
set icorrect 0
set ierrors 0
set ncorrect 0
set nerrors 0
set speed 1000
set triallength 2000
boxes blue
end
to go
tick
;blank screen
if (ticks mod triallength = 1) [
update-monitors
blank
set canrespond? false
boxes blue
set targetpos ((random 2) + 1) ; 1 - 2
set sumratio ratio-valid + ratio-invalid + ratio-neutral ;1-valid, 2-invalid, 0-neutral
set dice (random sumratio) + 1
ifelse(dice <= ratio-valid) [
set trialtype 1 ;valid
]
[
ifelse(dice > (ratio-valid + ratio-invalid))
[set trialtype 0] ;neutral
[set trialtype 2] ;invalid
]
]
;fixation cross
if ((ticks - 500) mod triallength = 0) [paintfixation]
;cue
if ((ticks - (1000 - SOA)) mod triallength = 0)
[
if(trialtype = 1)[
;valid
ifelse(targetpos = 1) [leftcue] [rightcue]
]
if(trialtype = 2)[
;invalid
ifelse(targetpos = 2) [leftcue] [rightcue]
]
if(trialtype = 0)[
;neutral
neutralcue
]
]
;target
if ((ticks - 1000) mod triallength = 0) [
ifelse(targetpos = 1)[lefttarget] [righttarget]
set onsettick ticks
set canrespond? true
]
end
to setrt
set rtime (ticks - onsettick)
end
to leftkey
keypress 1
end
to rightkey
keypress 2
end
to keypress [keyn]
if(canrespond? = true)
[
set canrespond? false
setrt
ifelse(targetpos = keyn)
;correct response
[
setfeedback true
;valid
if(trialtype = 1)[
set validlist lput (rtime) validlist
set vcorrect (vcorrect + 1)
]
;invalid
if(trialtype = 2)[
set invalidlist lput (rtime) invalidlist
set icorrect (icorrect + 1)
]
;neutral
if(trialtype = 0)[
set neutrallist lput (rtime) neutrallist
set ncorrect (ncorrect + 1)
]
update-plot
]
;wrong response
[
setfeedback false
;valid
if(trialtype = 1)[
set verrors (verrors + 1)
]
;invalid
if(trialtype = 2)[
set ierrors (ierrors + 1)
]
if(trialtype = 0)[
set nerrors (nerrors + 1)
]
]
]
end
to paintfixation
create-fixations 1
[
setxy 0 0
set size 1
set shape "x"
set color blue
facexy 0 10
]
end
to leftcue
setcue 1
end
to rightcue
setcue 2
end
to setcue [side]
ifelse(cuetype = "central")
[
create-cues 1
[
setxy 0 0
set size 3
set shape "default"
set color green
ifelse(side = 1) [facexy -10 0] [facexy 10 0]
]
]
[ ;ifelse central else: peripheral or symbolic
ifelse(cuetype = "peripheral")
[
ifelse(side = 1) [leftbox green] [rightbox green]
]
; symbolic
[
ifelse(side = 1)
[ ;left cue
;create-csymbols 1
create-cues 1
[
setxy 0 0
set size 3
set shape "pentagon"
set color green
]
]
[ ;right cue
;create-tsymbols 1
create-cues 1
[
setxy 0 0
set size 3
set shape "triangle"
set color green
]
]
]
]
end
to neutralcue
ifelse(cuetype = "peripheral")
[
leftbox green
rightbox green
]
[ ;central or symbolic central
create-cues 1
[
setxy 0 0
set size 3
set shape "dot"
set color green
]
]
end
to lefttarget
settarget 1
end
to righttarget
settarget 2
end
to settarget [side]
create-targets 1
[
ifelse(side = 1) [setxy -10 0] [setxy 10 0]
set size 3
set shape "star"
set color yellow
]
end
to setfeedback [correct?]
create-feedbacks 1
[
setxy 0 -7
set size 3
ifelse(correct?) [set shape "face happy"] [set shape "face sad"]
ifelse(correct?) [set color green] [set color red]
]
end
to blank
ask fixations [die]
ask cues [die]
ask targets [die]
ask feedbacks [die]
ask csymbols [die]
ask tsymbols [die]
;clear-turtles
end
to boxes [bcolor]
;ca ;; clear everything
leftbox bcolor
rightbox bcolor
end
to leftbox [bcolor]
;left box
ask patches[
;; if patches are between (0,0) to (0,edge)...
if ( pxcor = -13 and pycor >= -3 and pycor <= 3 )
[set pcolor bcolor] ;; ... draws left edge in red
;; if patches are between (edge,0) to (edge,edge)...
if ( pxcor = -7 and pycor >= -3 and pycor <= 3 )
[set pcolor bcolor] ;; ... draws right edge in red
;; if patches are between (0,0) to (edge,0)...
if ( pycor = -3 and pxcor >= -13 and pxcor <= -7 )
[set pcolor bcolor] ;; ... draws bottom edge in red
;; if patches are between (0,edge) to (edge,edge)...
if ( pycor = 3 and pxcor >= -13 and pxcor <= -7 )
[set pcolor bcolor] ;; ... draws upper edge in red
]
end
to rightbox [bcolor]
;rigth box
ask patches[
;; if patches are between (0,0) to (0,edge)...
if ( pxcor = 13 and pycor >= -3 and pycor <= 3 )
[set pcolor bcolor] ;; ... draws left edge in red
;; if patches are between (edge,0) to (edge,edge)...
if ( pxcor = 7 and pycor >= -3 and pycor <= 3 )
[set pcolor bcolor] ;; ... draws right edge in red
;; if patches are between (0,0) to (edge,0)...
if ( pycor = -3 and pxcor >= 7 and pxcor <= 13 )
[set pcolor bcolor] ;; ... draws bottom edge in red
;; if patches are between (0,edge) to (edge,edge)...
if ( pycor = 3 and pxcor >= 7 and pxcor <= 13 )
[set pcolor bcolor] ;; ... draws upper edge in red
]
end
to update-monitors
if((vcorrect + verrors) > 0) [
set vrate (vcorrect / (vcorrect + verrors))
]
if((icorrect + ierrors) > 0) [
set irate (icorrect / (icorrect + ierrors))
]
if((ncorrect + nerrors) > 0) [
set nrate (ncorrect / (ncorrect + nerrors))
]
if (length validlist > 0) [
set vmeanrt mean validlist
]
if (length invalidlist > 0) [
set imeanrt mean invalidlist
]
if (length neutrallist > 0) [
set nmeanrt mean neutrallist
]
end
to update-plot
set-current-plot "ReactionTime"
set-current-plot-pen "valid"
if (length validlist > 0) [
plot mean validlist
]
set-current-plot-pen "invalid"
if (length invalidlist > 0) [
plot mean invalidlist
]
set-current-plot-pen "neutral"
if (length neutrallist > 0) [
plot mean neutrallist
]
end