Verbal short-term memory reflects the sublexical organization of the phonological language network: Evidence from an incidental phonotactic learning paradigm

Abstract

The nonword phonotactic frequency effect in verbal short-term memory (STM) is characterized by superior recall for nonwords containing familiar as opposed to less familiar phoneme associations. This effect is supposed to reflect the intervention of phonological long-term memory (LTM) in STM. However the lexical or sublexical nature of this LTM support is still debated. We explored this question by using an incidental phonological learning paradigm. We exposed adults and 8-year-olds to an artificial phonotactic grammar that manipulated exclusively sublexical phonological rules. After incidental learning, we administered a nonword repetition STM task, with nonwords being either legal or illegal relative to the artificial phonotactic grammar. STM performance was significantly higher for legal than illegal nonwords, in both children and adults. These results demonstrate that verbal STM is indeed influenced by sublexical phonological knowledge. Moreover, verbal STM appears to reflect very subtle and automatic changes in the organization of the phonological network.

tDCS to temporoparietal cortex during familiarisation enhances the subsequent phonological coherence of nonwords in immediate serial recall

“…Since the linguistic characteristics of the nonword sets were controlled (e.g., in terms of phonotactic frequency, number of phonological neighbours, plus the frequency with which particular phonemes occurred within the stimuli) and the allocation of these sets to each experimental condition was counterbalanced between participants, we can be confident that the highly reliable difference in ISR between familiarised and unfamiliar nonwords reflected the opportunity to learn their phonological forms. This indicates that verbal STM receives substantial support from long-term information about phonological sequences that occur within the language, even when this information is newly acquired on the basis of on a few presentations (for similar conclusions from single item repetition see Majerus, Linden, Mulder, Meulemans, & Peters, 2004). …”

Lexical learning in bilingual adults: The relative importance of short-term memory for serial order and phonological knowledge

“…As we have mentioned before, a number of studies suggest that the more detailed and finely grained the structure of the phonological network, the higher the efficiency of nonword segmentation and temporary representation (e.g., Metsala, 1999). This reliance on sublexical phonological knowledge in the item STM task was also directly controlled by contrasting nonwords with high or low phonotactic frequency patterns relative to English phonology; these nonwords differ according to sublexical frequency (frequency of phoneme co-occurrences) but also lexical frequency measures, nonwords containing more frequent phoneme associations having typically a higher number of lexical neighbours (e.g., Majerus et al, 2004;Thorn & Frankish, 2005).…”

“…A number of studies show that long-term phonological knowledge influences STM performance, as reflected by better recall for words of high versus low lexical frequency or for nonwords containing high versus low probability phonotactic patterns (e.g., Gathercole, Frankish, Pickering & Peaker, 1999;Majerus, Van der Linden, Mulder, Meulemans, & Peters, 2004;Thorn & Gathercole, 1999;Thorn & Frankish, 2005; see also Goh &Pisoni, 2003, andRoodenrys &Hinton, 2002, for related findings). Furthermore, although phonological STM capacity at Age 4 predicts vocabulary knowledge at Age 5, this relationship later reverses, with vocabulary knowledge at Age 5 predicting phonological STM capacity at Age 6 (Gathercole et al, 1992).…”

Serial-order short-term memory predicts vocabulary development: Evidence from a longitudinal study.

“…familiar words differing from the nonword by a single phoneme (Majerus et al, 2004;Vitevitch & Luce, 1998). Serial order processing requirements were reduced given that only one item had to be maintained for each trial and given that, at the sublexical level, all items had the same short monosyllabic structure.…”