Millisecond Forums

Hi, We currently have our dot probe experiement on eprime but we want to switch to inquisit.

Does anyone have a sample experiement we could use please? Our study involves presenting two photos (one critical face and one compassionate face) on the screen for 500 milliseconds and then replacing one of the photos with either a : or ..

The particpant is required to click on on the dots as quickly as possible. And hopefully reaction times will show us where the attentional biases were.

Thank you!

Lucy and Shiv.

Hi Lucy and Shiv,

the Inquisit helpfile contains a Dot Probe Tutorial (also available online: http://www.millisecond.com/support/docs/v2/html/tutorials/dot%20probe/dottutorial.htm). You might want to work through this to (a) get familiar with the Inquisit basics and (b) get hints for programming your own Dot Probe paradigm. Try this and if you get stuck, I'll be here to help.

Best wishes from a fellow Inquisit user,

~Dave

Hi Dave,

Thanks for your quick reply!

We have followed that tutorial and ran the experiment with the words. However we are unsure about how to get our photos up instead of the words. (We've been trying for a few hours now and are getting quite frustrated!)

Also in the example they use an input of voicekey, we would like to use two keys on the keyboard instead, say A and L. How would we go about doing this?

Thanks for your help!

Lucy and Shiv.

You need to use <picture> elements instead of <text> elements.

Here you need to change the '/ inputdevice' setting to keyboard. You also need to modify the the '/ validresponse' and '/ correctresponse' settings to reflect this change, e.g.

<trial mytrial>
/ inputdevice = keyboard
/ validresponse = ("a", "l")
/ correctresponse = ("a")
[...]
</trial>

Hope this helps,

~Dave

Thanks Dave,

You're very helpful!

We are going to have one female and one male (2 photos each - critical and compassionate). We need the critical face of each to at first be on the left hand side and then the right hand side, to control for hemispheric lateralisation. Therefore there will be four sets of faces/dots in each section.

We would like our faces to be replaced with either a : or .. - half the time over the compassionate face and half the time over the critical face, and at the same half the time with a : and the other with ..

Is this possible?

We have amended the script to this, can you spot any problems?:

<picture>

/ items = FCritical.bmp

/ items = FCompassionate.bmp

/ position = (50%, 40%)

</picture>

<text targetleft> 

/ items = ("          :          ")

/ position = (50%, 40%)

</text>

<text targetright> 

/ items = ("          ..          ")

/ position = (50%, 60%)

</text>

<text focuspoint> 

/ items = ("          +          ")

</text>

<page intro>

^^^Dot Probe Task

^^Welcome and thank you for participating in this task.

^^Welcome to the experiment.

</page>

<page task>

Dot Probe Task Instructions:^^

^^The trials in the following task will go as follows:

^1. Look at the fixation point " + "

^2. Then two pictures will flash on the screen.

^3. Then you will see either  :  or  .. 

^Your task is to indicate as quickly as possible if you saw  :  or  .. 

^Press the spacebar to START THE TRIAL

</page>

<page taskreminder>

Reminder: ^Your task is to indicate as quickly as possible if you saw  :  or  .. 

</page>

<page end>

The Dot Probe Task is now concluded.

^^This task illustrates the effect of attention on processing visual stimuli.

</page>

<instruct>

/ nextkey = (" ")

/ lastlabel = ("Press the spacebar to continue")

/ nextlabel = ("Press the spacebar to continue")

/ fontstyle = ("Arial", 16pt)

</instruct>

<trial mytrial> 

/ stimulustimes = [1=focuspoint; 500=targetleft, targetright]

/ inputdevice = keyboard

/valid response = ("a", "l")

/correct response = ("a)

</trial>

<expt>

/ preinstructions = (intro, task, taskreminder)

/ postinstructions = (end)

/ blocks = [mytrial]

</expt>

<defaults>

/ fontstyle = ("Courier New", 16pt)

/ posttrialpause = 500

</defaults>

Yes, it is possible. However, things may be a little awkward to implement with Inquisit 2 (i.e. Inquisit 3 has some features which one could use to handle this more elegantly). Anyway, the strategy applicable to Inquisit 2 basically comes down to setting up a separate <trial> element for each unique combination of your within-subjects factors. Based on your description, I think you need the following

male-critical(left)-compassionate(right)-:(left)-..(right)
male-critical(left)-compassionate(right)-:(right)-..(left)
male-critical(right)-compassionate(left)-:(left)-..(right)
male-critical(right)-compassionate(left)-:(right)-..(left)

female-critical(left)-compassionate(right)-:(left)-..(right)
female-critical(left)-compassionate(right)-:(right)-..(left)
female-critical(right)-compassionate(left)-:(left)-..(right)
female-critical(right)-compassionate(left)-:(right)-..(left)

resulting in eight different <trial> elements each with their particular set of stimulus elements (<picture> and <text>) to draw from. Additionally, you'll want to take a closer look at how exactly the balancing / sequencing is done in the original experiment (i.e. the E-Prime version).

~Dave

Hi again Dave,

Where do we need to save the pictures? We used the template you gave us above. And name the photos fcritical, mcritical etc. But when we ran the experiment it said 'cannot locate item fcritical.bmp'

With the 8 elements above do we need to split them into 8 trials, <trial 1>, <trial 2> etc or can they go in a list together?

Thanks,

Lucy and Shiv

Hi,

Ignore that message - we have worked on the script some more and arre now getting just one error message

"name of element is missing"

Please could you advise

Here is the script so far:

<text targetleft> 
/ items = ("          :          ")
/ position = (50%, 40%)
</text>

<text targetright> 
/ items = ("          ..          ")
/ position = (50%, 60%)
</text>

<text focuspoint> 
/ items = ("          +          ")
</text>

<page intro>
^^^Dot Probe Task
^^Welcome and thank you for participating in this task.
^^Welcome to the experiment.
</page>

<page task>
Dot Probe Task Instructions:^^
^^The trials in the following task will go as follows:

^1. Look at the fixation point " + "
^2. Then two pictures will flash on the screen.
^3. Then you will see either  :  or  .. 

^Your task is to indicate as quickly as possible if you saw  :  or  .. 

^Press the spacebar to START THE TRIAL
</page>

<page /taskreminder>
Reminder: ^Your task is to indicate as quickly as possible if you saw  :  or  .. 
</page>

<page end>
The Dot Probe Task is now concluded.
^^This task illustrates the effect of attention on processing visual stimuli.
</page>

<instruct>
/ nextkey = (" ")
/ lastlabel = ("Press the spacebar to continue")
/ nextlabel = ("Press the spacebar to continue")
/ fontstyle = ("Arial", 16pt)
</instruct>

<trial criticalleft> 
/ stimulustimes = [1=focuspoint; 500=targetleft, targetright]
/ inputdevice = keyboard
/ validresponse =("a", "l")
/ correctresponse = ("a")
/ timeout = 10000
</trial>

<trial criticalright> 
/ stimulustimes = [1=focuspoint; 500=targetleft, targetright]
/ inputdevice = keyboard
/ validresponse =("a", "l")
/ correctresponse = ("l")
/ timeout = 10000
</trial>

<trial compassionleft> 
/ stimulustimes = [1=focuspoint; 500=targetleft, targetright]
/ inputdevice = keyboard
/ validresponse =("a", "l")
/ correctresponse = ("a")
/ timeout = 10000
</trial>

<trial compassionright> 
/ stimulustimes = [1=focuspoint; 500=targetleft, targetright]
/ inputdevice = keyboard
/ validresponse =("a", "l")
/ correctresponse = ("l")
/ timeout = 10000
</trial>

<block critical>
/ trials = [1-2=noreplace(criticalleft, criticalright)]
</block>

<block compassion>
/ trials = [1-2=noreplace(compassionleft, compassionright)]
</block>

<expt>
/ preinstructions = (intro, task)
/ postinstructions = (end)
/ blocks = [1=critical; 2=compassion]
</expt>

<defaults>
/ fontstyle = ("Courier New", 16pt)
/ posttrialpause = 500
</defaults>

You have an illegal character in

<page /taskreminder>
Reminder: ^Your task is to indicate as quickly as possible if you saw  :  or  ..
</page>

~Dave

Thank you so much for all your help.

We have just ran the experiment, however our photos have not come up - only the : and ..

Also we would like these on the left and right, not above one another....

Thanks again, you're a [*]

Lucy and Shiv