change of reinforcement contingencies across participants

[Leisha Wharfield]

Hi, Stephane,

I never worked out arrays either, but I did something a lot like this. I 
would embed another list under Correct and Incorrect that allowed as 
many other values as you like. Say for Correct you have +900 +700 +500 
+300 & +100. That is five different values. Embed a list under Correct 
called CorrectValues, for example. To do this, you put the name of the 
list in brackets in the list you already have, so it looks like this: 
[CorrectValues]. CorrectValues will have 5 different rows & the variable 
[Value] must match what is on your screen. So the screen that shows that 
value will say [Value] not [Correct]. You can rearrange these names any 
way you want to, but the name of the variable that matches the screen 
will be the same as in the embedded list, if you are following me.

To be sure that the cow is always worth whatever value that it picks for 
the same subject, say every time the cow appears you win $500, have the 
embedded list pick based on subject number. This might result in every 
fifth subject getting the same pair of + & - numbers, though. I'm not 
sure. Maybe someone else could help with that part.

Hope this helps,

Leisha

De Brito, Stephane wrote:

> Dear E-prime experts,
>
>  
>
> I am working on a task in which the participant is presented with 
> pairs of picture on the screen. I have 10 different pictures and each 
> picture is associated with a reinforcement value which stays the same 
> throughout the experiment (e.g. the cup  always wins you 900 points 
> and the cow always looses you 900 points). On each trial, the 
> participant has to choose one of the two pictures presented (press 'q' 
> for left hand side picture and 'p' for right hand side picture) and 
> win has many points has he can. The reinforcement values are +900 +700 
> +500 +300 +100 -100 +300 +500 +700 +900. Sometimes the participant is 
> presented with 2 pictures associated with punishment (pun-pun trials) 
> and has to choose the one associated with the lowest punishment (i.e. 
> scored as correct); on pun-rew trials the rew is scored as correct and 
> on rew-rew trials the pictures with highest reinforcement value is 
> scored as correct.
>
>  
>
> The task is running fine, but I would like to change across 
> participants the reinforcement contingency for each picture so that, 
> for example, not every participant wins 900 point when they choose the 
> cup. At the moment, I have the following attributes in my listobject:
>
>  
>
> Picture1
>
> 	
>
> Picture2
>
> 	
>
> Slidestate
>
> 	
>
> CorrectAnswer
>
> 	
>
> Correct
>
> 	
>
> Incorrect
>
> cup.bmp
>
> 	
>
> cow.bmp
>
> 	
>
> 1
>
> 	
>
> q
>
> 	
>
> You have won 900 points
>
> 	
>
> You have lost 900 points
>
> car.bmp
>
> 	
>
> spoon.bmp
>
> 	
>
> 3
>
> 	
>
> q
>
> 	
>
> You have lost 300 points
>
> 	
>
> You have lost 500 points
>
> Etc...
>
>  
>
> Basically, I would like to keep the pairing for my attributes 
> 'Correct' and 'Incorrect' the same, but I want to change across 
> participants the pairing in my 'Picture 1' and 'Picture 2' attributes. 
> I hope I made myself clear. From the e-prime manual and discussion 
> with colleagues, it seems that the best way to do this would be with 
> an 'array', but I have not managed to work it out yet.  Any idea on 
> how to achieve this would be greatly appreciated. Many thanks.
>
>  
>
> Best wishes,
>
> 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
>
>  
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listserv.linguistlist.org/pipermail/eprime/attachments/20070319/a95fe3de/attachment.htm>