This sample experiment demonstrates two methods for implementing an inter-trial interval.
The first block of this experiment uses a nested List object to select a random inter-trial interval from a set of specific values (i.e., 500, 1000, 1500, or 2000 milliseconds). The 'ITIDur' attribute will select a value from the 'ITIList' randomly and independent of the trial selected by the 'NestedTrialList' List object. The 'WaitITI' TextDisplay object has its 'Duration' property set to reference the 'ITIDur' attribute.
The second block of this experiment uses InLine script to select a random inter-trial interval between a set of boundaries. The Random function used in the 'SelectITI' InLine object will choose any integer value between the lower bound (500) and the upper bound (2000). The script then assigns the random value to the 'ITIDur' attribute, which is again referenced in the 'WaitITI' object’s 'Duration' property.