This article applies to:
For experiments where multiple sessions are required, the use of a counterbalanced List replaces the need for multiple experiment files (which would need opened for each session). A List Object can be counterbalanced by Subject, Session, or Group. By specifying this information at experiment startup, different ordering of stimuli can occur with the same experiment file. We recommend Counterbalancing a List instead of creating multiple experiment files whenever applicable.
Counterbalancing presents a single level based on the specified option in the Order By field. For example, if there are 2 levels in your List Object and the List is Counterbalanced by Subject, then Subject 1 would see Level 1 first and Subject 2 would see Level 2 first.
NOTE: If the OrderBy factor exceeds the number of levels, the modulus (the remainder of the subject number divided by the number of levels returned as a whole number) is used to determine the level.