Processing of syntactically complex sentences relies on verbal short-term memory: Evidence from a short-term memory patient

Abstract

The role of the phonological loop in auditory sentence comprehension was examined in a 35-year-old woman with a selective deficit of verbal short-term memory (STM). More specifically, the objective of the experiment was to test whether sentence comprehension is limited by number of propositions, as suggested by Rochon, Waters, and Caplan (2000), or whether it depends on syntactic complexity. In an offline task, severe impairment was present on cleft objects and centre-embedded structures; the deficit on object relatives in right peripheral position was less relevant, and the patient was able to handle sentential coordination easily. In an online task, her processing of centre-embedded structures and object relatives in right peripheral position was significantly slower than that in controls. She was also significantly slower in processing the verb of the object relative in centre-embedded structures. The results obtained do not support the claim that the difficulties encountered by patients with limited working-memory resources are due to the number of propositions in the sentence; they do, however, suggest a direct involvement of the phonological loop in processing syntactically complex sentences.

Role for memory capacity in sentence comprehension: Evidence from acute stroke

“…The finding of an association between STM and sentence comprehension is in line with a number of studies from participants with brain damage, including both case studies (e.g., R. Martin et al, 1994; Papagno et al, 2007) and group studies (e.g., Caplan et al, 2013). A recent study of 61 participants with chronic aphasia by Caplan and colleagues (2013), for example, found that both STM and WM were related to a number of sentence comprehension abilities.…”

“…Martin & Romani, 1994; R. Martin et al, 1994; Papagno, Cecchetto, Reati, & Bello, 2007; Vallar & Baddeley, 1984; cf. Butterworth, Campbell, & Howard, 1986).…”

“…These accounts have placed different emphases on the type of linguistic representations that are maintained. Some have focused on the importance of the short-term retention of phonological information (e.g., Friedrich, R. Martin, & Kemper, 1985; Papagno et al, 2007; Vallar & Baddeley, 1984; cf. Caplan, Michaud, & Hufford, 2013), as might be measured by Baddeley and Hitch’s (1974) phonological loop.…”

“…Caplan, Michaud, & Hufford, 2013), as might be measured by Baddeley and Hitch’s (1974) phonological loop. Phonological representations, for example, may be important when verbatim, ordered content or syntactic dependencies need to be maintained in order to parse a sentence (e.g., Papagno et al, 2007; Vallar & Baddeley, 1984; see Cecchetto & Papagno, 2011, for a review), as might be the case with, for example, center-embedded relative clauses. In contrast, others have focused on the importance of the short-term retention of lexical-semantic information (e.g., R.…”

Cognition counts: A working memory system for ease of language understanding (ELU)

“…Under conditions of mismatch, syntactic and semantic processing may be more tightly intertwined to allow for sentence reconstruction. This feature of the ELU model may explain why the role of WM in the sentence processing level of speech understanding has not been consistently demonstrated: some results appear to show a heavy dependence on the (explicit) phonological loop functions of WM in sentence comprehension (Papagno et al, 2007), whereas others show that syntactically challenging sentences can be processed online without taxing WM (Waters & Caplan, 2005). Nevertheless, at a neural level there seems to be agreement regarding a specialized region for syntactic processing in the pars opercularis in the inferior frontal gyrus.…”