Effect of Spaced Repetitions on Amnesia Patients' Recall and Recognition Performance

This study examined the effects of repetition and spacing of repetitions on amnesia patients' recognition and recall of a list of words. Like controls, amnesia patients recognized items better when repetitions were spaced compared with when they were massed. This finding was attributed to the additional rehearsal that distributed presentations typically encourage. Amnesia patients also showed normal spacing effects in a recall task, suggesting that they were able to benefit from the variable encoding that spaced repetitions allow to establish additional retrieval cues. However, even though instructions to encode repeated items in a variable manner enhanced massed presentations to the point where spacing no longer produced an advantage for the normal controls, it did not have a similar effect for the amnesia patients. This led to the conclusion that amnesia patients cannot take advantage of strategically provided opportunities to enhance their variable encoding of interitem associations. Instead, it is suggested that the automatic activation of different aspects of items and interitem associations is responsible for the spacing effect in their recall.