 Sessions can be conducted with a fixed delay or the delay can be systematically increased during the session in order to identify a threshold at which the participant is no longer able to respond correctly. For example, on the first trial, the delay may be zero second and then the delay may be increased by 4 seconds on each subsequent trial, contingent on correct responsse on the previous trial. The data are then analyzed to determine the longest delay at which the participant was consistently correct at 80 accuracy. This threshold can be considered a measure of the participants short term memory at the time of the session. 