clarification on counterbalancing question

[Susan G. Campbell]

You can do this if you have all of the stimuli in the same list (a row
for 1, 2, etc.) that's nested within your presentation list, and then
pick which column is chosen from in the presentation list (a, b, etc.).
You can randomize both lists to get randomization of the rows and
columns, or you could present one or the other sequentially to get 1,2,3
or a,b,c.

 

A STEP script that does this is the one replicating Lukatela and
Turvey's 1994 priming experiments (either version should work).  It has
all of the primes listed in a single list, and then picks the kind of
prime when it randomizes.  The subject wouldn't see a target more than
once, but the type of prime they see with each target is randomized, as
well as the order of the targets.

 

Hope this helps,

Susan

 

Susan Campbell

Graduate Research Assistant

University of Maryland

Center for Advanced Study of Language

________________________________

From: eprime at mail.talkbank.org [mailto:eprime at mail.talkbank.org] On
Behalf Of LoCasto, Paul C. Prof.
Sent: Tuesday, October 31, 2006 10:54 AM
To: eprime at mail.talkbank.org
Subject: clarification on counterbalancing question

 

Hello all-

 

I see I might have been unclear in my original post- I apologize. I am
aware of being able to create a number of lists- and for each list
counterbalance stimuli manually i.e:

 

List 1= 1a, 2b, 3c, 4a, 5b, 6c,

List 2= 1b, 2c, 3a, 4b, 5c, 6a

List 3= 1c, 2a, 3b, 4c, 5a, 6b

 

and then at the Block level have E-prime choose to present one of these
lists using the counterbalance display option. However, unless I
manufacture each possible list sequence this is really pseudorandom in
that anyone who sees stimulus 1a, will also see stimulus 4a and 5b etc. 

 

Would someone be so kind as to tell me how I might list my stimuli in a
way that has E-prime *randomly* select whether a Ss sees version 'a',
'b', 'c' of a given stimulus and across the whole experiment would see
an equal number of stimuli across the three conditions (a, b, c) where
no stimulus (e.g. stimulus 1)  was seen in more than one version (e.g.
1a *or* 1b *or* 1c). 

 

I would really appreciate any insight you can afford. Thanks.

 

 

Paul

 

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