spatial alternation task

[Leisha Wharfield]

Hi, Stephane,

I can't get "Do While" or "Do Until" scripts to work for me, either, 
despite studying the syntax and getting help from people here. I don't 
know why they don't work, even when I just copy examples.

So the first Slide is the introductory Slide where both responses are 
correct, so it is always the same. That's easy. Just include either the 
Left or Right response as Allowable in the Slide object properties and 
make the Slide terminate when an allowable response is entered. After 
that Slide, you want to get the Response via an Inline object and use it 
to set up the next slide, right? I would use an If, because they work 
for me.

So that if Slide1.RESP is Left (or whatever the Left response is), Then
    Slide2.CRESP or Correct Response = Right (or whatever the Right 
response is).
    Draw the £20 on the Right side of the Slide2 screen

ElseIf Slide2.RESP is Right, Then
    Slide2.CRESP = Left
    Draw the £20 on the Left side of Slide2 screen

EndIf, with this Inline Object followed by a Label and then Slide2.

After Slide2 I would have another Inline Object that gets Slide2.CRESP, 
& another If

If Slide2 response is correct, Then
    Change correct response
    Draw £20 on the other side of the screen
EndIf

Goto the Label before Slide2 (because no change is made if the subject 
is wrong, right?)

The two other things you would need in this Inline Object is first, 
writing your data to a text file or into your e-data file (I put time 
stamps in to make sure my response times are accurate), since I think if 
you don't do this you will only get the data from the last time you run 
Slide2; and second, you will need some way out of this Iffy loop. How 
does it end? After a certain number of trials, or after a certain number 
of correct answers, or after a certain amount of time? I don't know, but 
you will need to establish some attribute that keeps track of that 
number & check it after each run of Slide2 in the Inline Object that 
occurs after Slide2 so that you can exit gracefully at the end of the task.

Other people on the list will tell you a better way to do this; they may 
even give you a Do While that works.

Leisha Wharfield
Decision Research
Eugene, Oregon, USA

De Brito, Stephane wrote:

> Dear e-prime experts,
>
>  
>
> I am a novice in the e-prime world and would need a bit of help. I am 
> working on a spatial alternation task (Blair et al., 2006, 
> Neuropsychology, Vol 20, No 2, pp.153) but have difficulties 
> implementing it.
>
>  
>
> Task description:
>
> the participant sees 2 red cars on each side of the screen and has to 
> figure out which one is baited with a £20 note. The participant task 
> is to learn  that the side behind which the £20 note is located is 
> being alternated after each correct response. After each correct 
> response, a £20 note appear on the screen on the side selected.
>
>  
>
> On the first trial, both sides are baited with a £20 note (so both 
> responses are correct). For the 2nd trial the £20 note is located 
> behind the side not chosen on the 1st trial. On each subsequent trial 
> following a correct response, the other side is baited. After 
> incorrect response, the £20 note remains on the same side until the 
> participant makes a correct response.
>
>  
>
> My questions are:
>
>  
>
> 1)Is it possible to have 2 correct answer on the 1st trial? If yes, 
> does it have to be implemented with a script or can it be done with 
> the e- studio interface?
>
>  
>
> 2) I know that for this paradigm I need to use contingent branching 
> and a "Do While" or "Do Until" loop in the script. I have read the 
> manual and tried different scripts, but without success. Any advice 
> would be very much appreciated.
>
>  
>
> Best,
>
>  
>
> stephane
>
>  
>
>  
>
> ------------------------------------------
>
> Stephane De Brito, PhD student
>
> Institute of Psychiatry
>
> King's College London
>
> Forensic Mental Health Science Department
>
> Box P023
>
> De Crespigny Park
>
> Denmark Hill
>
> London SE5 8AF
>
> United Kingdom
>
> Tel: + 44 (0) 20 7848 0711
>
> Fax: + 44 (0) 20 7848 0754
>
> website: www.iop.kcl.ac.uk
>
>  
>
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