Sublexical or lexical effects on serial recall of nonwords?

S. E. Gathercole, C. R. Frankish, S. J. Pickering, and S. Peaker (1999) reported 2 experiments in which they manipulated phonotactic properties of nonword stimuli and observed the effects on serial recall. Their results show superior recall for items consisting of more frequent phoneme pairs (biphone frequency). Biphone frequency was counted as the number of 3 phoneme words in which the phoneme pair occurs. In the first experiment of the current article, the authors made the same manipulation while controlling for the number of lexical neighbors and found no effect of biphone frequency. In the second experiment, the authors manipulated neighborhood size while controlling biphone frequency and found a significant effect of neighborhood size. The authors argued that serial recall of nonwords is influenced by lexical rather than sublexical knowledge.