Folder with multiple stimuli

[alex iyer]

Dear e prime gurus,

I am putting together an experiment that is designed as follows:

Fix cross
(Image 1)
Fix cross
(Image 2)
Text object asking if they are the same.

The stimuli consist of 24 different faces with 3 different emotions. If the emotions are different but the faces are the same, then the answer is the same. So image 1 and image 2 are going to be pulled from the same folder: the two stimuli could, in theory, be the same one, but the trials themselves shouldn't repeat. I have a LOT of images though, so any ideas on how to reference just the folder and tell Eprime to pull up an image on that folder at random?

Thanks!

[David McFarlane]

If I understand you correctly, then you have a total of 72 images (24
faces x 3 emotions/face). You have these split somehow among separate
folders (i.e., directories) on the computer. On any trial, you want
E-Prime to pull two images randomly from a designated folder.

Well, putting your image file names into a List will randomize them, and
in the File name property of your ImageDisplay or SlideImage object, you
can always mix a literal folder name with an attribute reference for the
file name, e.g.,

Faces1Folder/[FaceFile]

(yes, you should use a forward slash rather than a backslash for a path
separator in E-Prime).

If you want to randomize what folder to use, then put the folder names
in a List and add that as another attribute reference, e.g.,

[FacesFolder]/[FaceFile]

You might even find nested Lists useful for this (see the Nested Lists
tutorial in the User's Guide that came with E-Prime).

You can do amazing things with E-Prime by judicious use of Lists, nested
Lists, and attribute references.

Does that help, or did I miss something?

---------------
David McFarlane
E-Prime training online:
http://psychology.msu.edu/Workshops_Courses/eprime.aspx
Twitter: @EPrimeMaster (https://twitter.com/EPrimeMaster)

[alex iyer]

Hi David,

                Thanks so much, that was very helpful!  So, I have a different problem now, which concerns interfacing the paradigm with netstation.

So, here is the "structure" of the paradigm:

Stimuli: 24 faces of 3 emotions each.  I have created nested lists with the 24 stimuli, but then within each of them you have the three possible emotions.  These three are just the file name of the stimulus (there is no associated label, except in the structure window, where the nested lists are named, for example "WhiteFemale2", based upon the race (the number is arbitrary)).  

           TrialList: in my actual trial ist, I have these columns" Weight, Nested, Procedure, Stim1 (labeled WF1,WF2, etc., which corresponds to a picture in the nested list, but does not specifically refer to the emotion) , Stim2 (Same idea as stim1), correctanswer, condition (same/different) and CellNumber, which I will use to interface with netstation.  

              In the actual trial, you will see one face, a crosshair, then another face, and asked whether the two faces are the same or different ( I know I described the experiment earlier, I just want to do it again in case!). 

 So, I have to make this thing called a "CellList" when I interface E-Prime with Netstation, and create something called a "cell-number".  This will correspond to a label I create next to this number for each trial.    

The problem is that the way I have it now, the cell number only refers to Stim1 within a trial, and does not specify the specific emotion.  So the two things I would like to do are:

1. have a different cell label for the first vs. the second picture that shows up in the trial

2. have the cell label specify which specific emotion of a given face is being referred to.

I am, quite frankly, at a loss on how to do this, and any help would be immensely appreciated!

I am more than happy to clarify in any way I can.

Thank you!

Arjun

[David McFarlane]

Arjun,

I do not use NetStation, so I do not have much more to offer. But I do
have one thought, in case it helps ...

Remember, you may compose an attribute value from other attribute
references. E.g., suppose CellList has an attribute (column) named
"CellNumber". In CellNumber, you could put [FacesFolder]-[FaceFile].
The resulting value of the CellNumber attribute would be the current
value from the FacesFolder attribute, followed by a dash, followed by
the current value from the FaceFile attribute. This may or may not
work, depending on where CellList appears in your structure.

(In fact, you may even use attribute references within attribute
references. E.g., A-[B-[C]] would first look up the current value of
the C attribute, then paste that to the end of the literal string "B-"
to form a new attribute reference, then look up the value of that
reference, and finally paste that value to the end of the literal string
"A-" to form the final value. Imagine the possibilities!)

But I do not know how NetStation uses a CellList. Perhaps someone else
who uses NetStation will weigh in.

-- David McFarlane