Randomization Woes

[SIZE=“3”]I am getting the impression that the only randomization function available in SuperLab 4.0 is to randomize trials within blocks. I cannot randomize blocks within participant groups, and I cannot randomize stimulus lists, and randomizing events within trials only randomizes the order in which the events are presented but not the stimulus lists within those events. When using a cue and only one other event, this effectively means there is no randomization. An odd failing for a program solely designed for stimulus presentation.

So, what this leaves me with is a random presentation of the same event pairs. The pairing never changes.

Does anyone have suggestions as to how I might randomize how stimuli are paired? For instance, I present a sentence followed by a picture, and I want the program to randomize which picture follows a particular sentence.

If I randomize by hand, any suggestions on how to put all the randomly ordered lists into the program?[/SIZE]

Stimulus lists can’t be randomized. This is only a problem if you use more than one stimulus list per trial (which you clearly are), as randomizing trials within a block gives you the same results as randomizing a stimulus list–if there is only one stimulus list being used per trial.

As far as randomizing by hand, it’s much easier to import a randomized list of sentences than pictures, as you can copy and paste the sentences into the stimulus list editor.

If you want each item in one stimulus list paired with each item in another list (i.e. two lists of ten becomes 100 trials, not ten), then here’s how you can do it:

Create your trial and lists as desired. Uncheck one of the two events using stimulus lists. In the experiment menu, select “Expand Events That Use Lists…” This will open a new experiment window. If the checked list had ten stimuli, the new experiment will have ten identical trials, each with one event created with each of the stimuli in your list. Now, highlight these newly created trials and check the other event using a stimulus list. When you run the experiment, it will be expanded again, but your stimulus lists will effectively be multiplied (instead of paired). The one downside to this method (assuming this is what you were even looking for to begin with) is that you lose the variability of one of the lists. After expanding, the stimulus list that was expanded is irrelevant–it has been converted into a bunch of trials and events. Changing the list will not change the experiment.