Repetition priming of words, pseudowords, and nonwords

In 5 experiments, the authors assessed repetition priming for words, pseudo words, and nonwords using a task that combines an implicit perceptual fluen cy measure and a recognition memory assessment for each list item. Words an d pseudowords generated a consistently strong repetition effect even when t here was a failure to recognize the stimulus. In 2 of the experiments, the repetition effect for nonwords was reliably above chance even when there wa s a failure to recognize the stimulus. The authors propose a parallel distr ibuted processing (PDP) model based on the work of J. McClelland and D. Rum elhart (1985) as a way to understand the mechanisms potentially responsible for the pattern of findings. Although the error-driven nature of learning in the model results in a poor fit to the nonword priming data, this is not endemic to all PDP models. Using a model based on Hebbian learning, the au thors instantiate a property that they believe is characteristic of implici t memory-that learning is primarily based on the strengthening of connectio ns between units that become active during the processing of a stimulus. Th is model provides a far more satisfactory account of the data than does the error-driven model.