Manipulate random order

I have a series of trials–each with a number of events linked to it–that I need to run in random order, but I want to prevent the trials from being run more than once in a single sitting. The events that are linked to the trials are lists, so each trial may occur as many times as there are items in the event lists (trial, 1; trial, 2; trial, 3; etc.). I need to stop these multiple occurrences and make sure each trial only appears once. Any thoughts?

Are you saying you only want one event from each trial presented?

Not exactly… I want every trial to be presented from each block. Since the events in those trials include lists, trials get repeated–using a different item from the event list. I want to prevent this repetition.

A trial that is using an event that has stimulus lists with let’s say 20 items, will essentially translate into 20 different trials at run-time. To get a clearer picture, go to the Experiment menu and select Expand Events that Use Lists.