So it should always be ABABABABABA... etc? If so, just assign all the A's a WGR of 1 and all the B's a WGR of 2. Yes?
So it should always be ABABABABABA... etc? If so, just assign all the A's a WGR of 1 and all the B's a WGR of 2. Yes?
the proportion is 4 A-type trials to 1 B-type trial. so it can be AAAAAAABABA etc.
I've been working on a nice simple notation system for creating constraints like that, but I haven't programmed it. Might be working by the next version. The only way I can think of to do this in v2006 would be to treat the BA's as BGR pairs and draw the stimuli randomly from stimlists as follows:
Code:BGR WGR STIM 1 0 $A 2 0 $A 3 0 $A 4 0 $A 5 0 $A 6 0 $A 7 0 $B 7 0 $A 8 0 $B 8 0 $A
Last edited by jarvis24; 04-11-2007 at 11:24 AM.
because i'm using compound screens, drawing the stimuli from a stimlist wouldn't work in my case.
after some thinking & consulting, i implemented the following solution:
since there are exactly 4 different A-type stimuli and only one B-type stimulus, i created 4 compound B trials: BA1, BA2, BA3, BA4. then i randomized these trials with the regular A trials:
WGR stim
1 A1
1 A2
1 A3
1 A4
1 BA1
1 A1
1 A2
1 A3
1 A4
1 BA2
and so on.
so, i've ensured that after each B trial there would be an A trial, but the stimulus for the particular A trial is randomized.
i hope this is clear.
michal.
So you stuck two trials together into one? i.e., whenever you have a B trial, you automatically get an A trial because it's actually stuck onto the end of that B trial?
that's exactly what i did. what do you think?
Clever!