Fig. 1.

Schematic of the conditional, three-stage, sequential, pre-post-retest design and protocol. The retest for stage I was set 6 months after the initial training session. If participants in stage I displayed successful retention (“Retention? Yes”), the retest of the stage II cohort would be set at 9 months; if the retention in stage I was unsuccessful (“Retention? No”), the stage II retest would be 3 months after the initial session. Subsequently, if retention in stage II was successful (“Yes”), the stage III cohort would retest 12 months after their initial session; if the stage II retest was successful but stage III retest was unsuccessful, the length of retention would be recorded as at least 10.5 months. If retention in stage I was successful but stage II was unsuccessful, the stage III retest would be 7.5 months after the initial session. If retention did not occur in stage I or stage II, the stage III retest would occur 1.5 months after its initial training (not shown). If stage I was unsuccessful but the stage II retest was successful, stage III would retest 4.5 months after initial training (also not shown). The overtraining in this block-and-random design consists of 24 slips (bottom), all of which are unannounced. No rehearsal is given prior to the first novel trial so subjects do not know where, when, or how a slip will occur