The company a word keeps: The role of neighbourhood density in verbal short-term memory

Psycholinguistic information plays an important role in verbal short-term memory (vSTM). One such linguistic feature is neighbourhood density (ND)-the number of words that can be derived from a given word by changing a single phoneme or single letter-with vSTM performance typically better when word sequences are from dense rather than sparse neighbourhoods. This effect has been attributed to higher levels of supportive activation among dense neighbourhood words. Generally, it has been assumed that lexical variables influence item memory but not order memory, and we show that the typical vSTM advantage for dense neighbourhood words in serial recall is eliminated when using serial recognition. However, we also show that the usual effect of ND is reversed-for both serial recall and serial recognition-when using a subset of those same words. The findings call into question the way in which ND has been incorporated into accounts of vSTM that invoke mutual support from long-term representations on either encoding or retrieval.