Random selection from a nested list

[AW]

I have a list of trials that will be drawing from a nested stimuli list. I want to randomly select items from the stimuli list, but there are more trials in the trial list than the number of stimuli in the stimuli list. I want to minimize the variability in repetitions in the stimuli list; i.e., I want the repetitions to be 3-4 times per stimulus, but according to my output, some stimuli are repeated only once and others 7 times. I assumed that the list would select stimuli from the nested list without replacement for a cycle and then go repeat another cycle once there are no items left, so I'm not sure why there is a high variability in repetitions. Currently the setting on the stimuli list is on "random selection no repeat after reset". 

Any advice is greatly appreciated!! :)

[David McFarlane]

What weight values do you have for the rows in your nested stimuli
List? Do you have those all set to 1? Do you have any rows that
repeat the same value?

It will help to simplify your program for test purposes. Replace your
nested stimuli List with one that has only 3 to 5 rows, with simple
values like A, B, C, ... Set that to Sequential order and see what
happens. You should get that to simply run sequentially through all
those rows, and then repeat over & over. Then set to Random and see
what happens -- you should get A, B, C, ... in some shuffled order,
then again, etc.

Finally, try setting your nested stimuli List back to Sequential
order. You should get all your stimuli to run in order, and then
again in that order, etc.

Write back with your results.

-- David McFarlane

[AW]

Hi David,

My apologies as it appears that I wasn't very clear with my question.

I have a list of trials, and for each trial, under the "nested" attribute, I draw from different lists of stimuli. For example, there are different types of trials, called match, no match, and each trial draws from 2 lists of stimuli, A or B. The trials for the trial list (match, no match) are sequentially selected; the trials for the stimuli list (A, B) is randomly selected. Because there are roughly 50 lines in the trial list but roughly 15 lines in the stimuli list, each stimuli will be repeated 3-4 times. However, I see from the output that some are repeated only once and others 7 times. I would like to draw from the stimulus list each cycle (randomly select from 15 lines, then when there are no more stimuli, randomly select from the 15 lines again), but this is not what appears to be currently happening, otherwise I believe all stimuli should be repeated either 3 or 4 times. 

Thank you again for your help!