randomizing blocks independently of trials, and silent video

[Susan Campbell]

I'm not sure precisely what you're asking here.  Do you want to have a
set of lists (blocks) and present them in a random order?  The simple
way to do that is to add a list above the blocks, create a procedure to
include each block, then randomize the order of that list.

So the list would look like this:

Weight	Procedure
1		Movie1
1		Movie2

and the structure would look like this:

NewList (List - randomized)
	Movie1 (Procedure)
		BlockList1 (List - sequential)
	Movie2 (Procedure)
		BlockList2 (List - sequential)

You can change the names of the logging levels from the Edit Experiment
window if that is a problem.

Hope this helps,
Susan Campbell
PsychMate Paradigm Developer

***Not speaking on behalf of my employer***

-----Original Message-----
From: James T. Myers [mailto:lngmyers at ccunix.ccu.edu.tw]
Sent: Monday, March 31, 2003 8:58 AM
To: E-Prime List
Cc: Language Processing Lab
Subject: randomizing blocks independently of trials, and silent video



I have a feeling there must be a simple way of doing this, but so far my
assistants and I haven't figured it out.  How can we get E-Prime to take
a
set of blocks, each with its own set of trials, and randomize the order
of
the blocks without making the blocks all the same?  Maybe there's some
default setting we're not turning off or something. 

By the way, the particular reason we want to do this right now is to
play
silent movies as primes in a sign language experiment.  We create each
movie as a block of sequentially ordered trials, where each trial
displays
a BMP still picture.  If I remember right, we have it set up now so that
we use every other frame from the original MPEG file and display it for
67
msec, and it looks quite acceptable for our purposes.  This method would
also seem to allow for collecting reaction times in the middle of a
movie. 
I know others on this list have been interested in using movies as
stimuli, and if silent movies will do, you could try this. 

But it all depends on being able to randomize the blocks....

James Myers
Graduate Institute of Linguistics
National Chung Cheng University
Min-Hsiung, Chia-Yi  621
TAIWAN, ROC
Email:  lngmyers at ccunix.ccu.edu.tw
Web:    http://www.ccunix.ccu.edu.tw/~lngmyers/
Phone:  886-5-242-8251
Fax:    886-5-272-1654