EXPRESS: Investigating a Metrical Hebb Effect for lists of words

In four experiments, we describe the first finding of a Metrical Hebb Effect. Participants are shown to exhibit a Hebb Repetition Effect for repeating, list-wide stress patterns across sequences of familiar words, even though the lexical items within the “repeating” lists do not themselves repeat. Experiment 1 established the presence of a Hebb effect for metrical patterns, demonstrating significant learning of list-wide metrical patterns over successive presentations. Experiment 2 investigated the effect's longevity, showing persistence of learned metrical information after a spacing of three non-repeating lists. Experiment 3 revealed that the effect did not persist over a longer spacing, of eight intervening lists. Experiment 4 investigated the learning mechanism, suggesting that chunking, rather than item-position binding, might account for the observed learning of metrical patterns. The authors propose that metrical-pattern learning represents a process of gradual integration of sequences of weak and strong stress accents, into higher-level units representing the stress patterns within, and across, words. We briefly discuss some implications of the Metrical Hebb Effect for phonological word-form learning, and for speech perception and production.