On one slide, show different images, loaded from a list

[liwenna]

Hi Vera

I see that you really researched well and you found all the 'elements'
you need, but you didn't use them in a way that works so far. I must
say that e-prime might not be the single most excellent program to
create a visual search task in... although I also wouldn't know what
program to better use.

One thing that is elemental to understand when using e-prime, is that
on each run of a procedure one level of each of the nested lists can
be used. If you need nine different pictures in one 'run of the
procedure' you can not put them in different rows as e-prime can only
acces one level of each list on each run. So... you wrote: " like
putting the 9 images in one line of the nested list, but then I get
other errors", and you were definitely on the right track!

Forget about the collumn referencing and the pointing towards
procedureslists first and then to nested lists.. you don't need it.
That's exactly the kind of programming that you don't want to use ;)

Do the nine images have the same positions on each trial? Or are they
placed in different 'arrangements' on every trial?
What you could do is make one (nested or direct) list that has nine
attributes on every row containing the nine pictures used in a trial,
call them for instance stim1, stim2, stim3,...stim8 and targetstim. In
each level of this list you can make a different combination of
stimuluspictures. In your slide you'll have nine imageobjects: make
each one of them refer to a different stimulus attribute: [stim1]
[stim2] ... [targetstim].

So far so good: now you'll have different collections of stimpictures
on each run (as many different 'collections' as you have made
different levels in your list). If you need them to be placed in
different spatial arrangement on each trial you should start out with
creating the number of different arrangements that you want to use.
For each arrangement write down the x and y values of each of the
imageobjects. (so: imageobject 1 showing [stim1] has x = 500 and y=68
in arrangement 1 and x = 950 and y =780 in arrangement 2  for
instance). Into the list with stimuluspictures nest a second list that
holds the different arrangements. This list will have 9x2=18
attributes: stim1x, stim1y, stim2x, stim2y, stim3x... targetstimy. Go
back to your slide and now tell the slideobjects to find their x and y
values in the corresponding attributes, just like they find their
pictures: [stim1x] [stim1y] [stim2x] etc etc.
Now... you'll have spent a lot of time but you will have a random
combination of a collection of target and distractorpictures with one
of the different spatial arrangements on each trial.

Alternatively.... I say it should be possible to use 'complete array'
pictures that you make in for instance photoshop or even paint....
pictures that have the size of the screen and show all nine stimuli at
once... you could tell e-prime to show one of those pictures on each
trial and locate a single 'transparant empty' imagobject over the
location of the targetstimulus (you should fiddle around a bit with a
non-transparant coloured object to find the exact location needed for
each 'array picture' and actually place this imageobject UNDER the
arraypicture and not in front).This imageobject will then be the
object to which you point your dohittest script (assuming that that's
what you will use? have your subjects click the mouse on the target?).
Not sure if that will work.. think it should.

I hope the above stuff will get you started again, if not, please let
me know.

Best

liw



On Mar 10, 5:45 pm, Vera <vera.d... at googlemail.com> wrote:
> Hi forum members!
>
> I sure hope I will get some help here! I am trying to construct a
> visual search task in which participants have to find let's say a
> "yellow triangle" within "blue triangles" and "yellow triangles".
>
> For this, I created a list with different conditions (like number of
> items on the grid, target present or not) and I was actually counting
> on using a slide with (let's say) 9 images, on which I would each of
> the 9 images randomly from a nested list.
>
> So I made my nested list with images (.png's) and I of course made
> sure to have the image-objects on the slide point first to the
> procedure list and then to the nested list (I think I read about all
> the messages concerning this topic, including this onehttp://groups.google.com/group/e-prime/browse_thread/thread/84c742b85...
> (thanks a lot for the work-around, it was a good thing for me to see
> if I did it right, which I did, but it still will not load the right
> pictures).
>
> So the problem is: It seems that the "point to the nested list
> function" is working, but then it seems impossible to load 9 DIFFERENT
> images (it will show me 9 times the same image, at least therewith
> confirming that it points to the correct nested list).
>
> And I tried every option I could think of (like putting the 9 images
> in one line of the nested list, but then I get other errors). :-( I am
> now believing that I should maybe really write to the developers,
> simply because this "functionality" seems to be absent.
>
> Now I will probably have to code it (which is were the real problem
> starts, because I am an absolute no-programmer ;-) ) and the institute
> where I am currently working actually bought E-Prime because it should
> be more or less "programming-free" (well ok, I understand you cannot
> rule it out completely, but the thing I described above should be
> possible in my opinion).
>
> I really hope some of you guys have some creative solution for me!
>
> With kind regards,
>
> Vera

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