An analysis of errors in the learning, overlearning, and forgetting of sequences.

This paper investigates the effects upon delayed recall of errors made during learning. Subjects learn a sequence of wagons in a model train over repeated presentation and test cycles. The recall of the same sequence is unexpectedly tested one week later. The results show that the errors subjects make during learning are a significant factor in predicting which elements of the sequence are forgotten. Learning is modelled by a population of discrete traces, accumulated during learning, which has two characteristics: First, many of the traces duplicate information encoded in other traces; and second, representations of the correct sequence coexist with traces containing incorrect information about the same elements of the sequence. Forgetting is modelled by the accretion of null traces that compete with correct traces of retrieval and the increasing inability with time to discriminate correct representations in memory from erroneous records. This model is shown to provide a good fit to the experimental results and suggests a strong link between the complete history of learning new material (including errors) and its subsequent likelihood of forgetting.