Phonological Working Memory Capacity Research Articles

Syntactic engagement of new words: The garden-path method applied to track sensitivity to structural ambiguity

This article proposes an innovative approach to examining garden-path (GP) effects in sentence processing. It applies GP effects as a method to a new domain, specifically to syntactic engagement of recently learned verbs. We tested twenty-seven English native speakers and twenty Spanish learners of English to verify method validity. Three main components characterise the method, namely training of new word meaning through definitions and example sentences, eye-tracking while reading plausible and implausible GP sentences after sleep consolidation, and a meaning recall test. We also examined if participants’ phonological working memory and vocabulary size play a role in how they syntactically engage new words. Results showed that recently learned verbs can elicit syntactic engagement in both native and nonnative readers. Both vocabulary size and phonological working memory capacity could predict ambiguity reprocessing, irrespective of language group. These results indicate that garden pathing can reliably signal effort to detect and resolve subject-object ambiguities in both first language (Frazier & Rayner, 1982; Pickering & Traxler, 1998) and second language readers (Chen et al., 2021, Jegerski, 2012). This feasibility study is a pioneering attempt to map new vocabulary knowledge as a window into emergent structural representations. The significance of this method lies in its potential to track syntactic engagement of new lexis, while accounting for individual differences, and following the principle that to know a word entails knowing its form, meaning, as well as its grammatical use (Nation, 2001).

Nonword repetition and identification skills in Kannada speaking school-aged children who do and do not stutter

PurposeThe present study employed nonword repetition and nonword identification tasks to explore the phonological working memory (PWM) abilities and its interaction with speech motor control in school-aged children who do and do not stutter. MethodParticipants were 17 children who stutter (CWS) (Age range = 7–12) and 17 age and gender-matched children who do not stutter (CWNS). For the nonword repetition task, the participants repeated sets of 2-, 3-, and 4-syllable nonwords (n = 12 per set). The participants silently identified a target nonword from a subsequent set of three nonwords (n = 12 per 2-, 3- and 4-syllable length) for the nonword identification task. The performance of CWS on the nonword repetition task was compared with the CWNS for the mean number of accurate repetitions, number of trials taken, number of accurate repetitions on initial trial, and number of fluent repetitions across the three-syllable conditions for the tasks. For the nonword identification task, the number of nonwords identified accurately by the two groups were subjected to analysis. ResultsCWS were significantly less accurate on the initial production of nonwords and required significantly more number of attempts to repeat the nonword accurately. Further for the nonword identification task, CWS were significantly less accurate than CWNS in correctly identifying the target nonword. ConclusionsThe present findings suggest that, in addition to limitations in PWM capacity, an unstable speech motor control system in CWS may lead to dysfluent speech.

Independent contributions of semantic and phonological working memory to spontaneous speech in acute stroke

Patients with left hemisphere stroke often have language deficits which impair their ability to produce phrases and sentences. One possible source of these speech impairments is the disruption of verbal working memory (WM). Single-case studies of chronic stroke have suggested the existence of a WM capacity specific to maintaining semantic information that is critical for preparing multiple words in phrases prior to speech onset (Freedman, Martin, & Biegler, 2004; Martin & Freedman, 2001; Martin & He, 2004; Martin, Miller, & Vu, 2004). The current study tested this hypothesis by examining spontaneous narrative language production and working memory capacities in a large sample of individuals at the acute stage of stroke (N = 36), prior to the reorganization of function or strategy development. Here we show using a multiple regression approach that patients' semantic but not phonological WM capacity had an independent contribution in predicting phrasal elaboration and increasing utterance length whereas patients’ phonological but not semantic WM capacity had an independent contribution in predicting a more rapid speech rate. Importantly, neither WM capacity independently predicted grammatical abilities in speech, implying that the other relations did not result from overall severity. These results indicate that separable semantic and phonological WM components exist that support different aspects of narrative speech. To our knowledge, this is the first study to examine spontaneous speech in a large group of acute stroke patients demonstrating a critical relationship between working memory and the ability to produce more words in phrases and longer utterances.

Mood induction in children: effect of the affective valence of a text on phonological working memory.

The influence of mood on working memory capacity has been investigated in adults, albeit with conflicting results, but remains relatively unexplored in children. The present study examined the effect of a mood induction procedure on phonological working memory capacity in fourth and fifth graders. An initial working memory span test was followed first by a collective mood induction procedure, then by a second working memory span test. Results showed an effect of mood induction procedure on phonological working memory performances, with decreasing scores in the case of negative mood. These results suggest that, in certain contexts and situations, negative emotion has an impact on children’s cognitive abilities.

Selective transfer of visual working memory training on Chinese character learning

Previous research has shown a systematic relationship between phonological working memory capacity and second language proficiency for alphabetic languages. However, little is known about the impact of working memory processes on second language learning in a non-alphabetic language such as Mandarin Chinese. Due to the greater complexity of the Chinese writing system we expect that visual working memory rather than phonological working memory exerts a unique influence on learning Chinese characters. This issue was explored in the present experiment by comparing visual working memory training with an active (auditory working memory training) control condition and a passive, no training control condition. Training induced modulations in language-related brain networks were additionally examined using functional magnetic resonance imaging in a pretest-training-posttest design. As revealed by pre- to posttest comparisons and analyses of individual differences in working memory training gains, visual working memory training led to positive transfer effects on visual Chinese vocabulary learning compared to both control conditions. In addition, we found sustained activation after visual working memory training in the (predominantly visual) left infero-temporal cortex that was associated with behavioral transfer. In the control conditions, activation either increased (active control condition) or decreased (passive control condition) without reliable behavioral transfer effects. This suggests that visual working memory training leads to more efficient processing and more refined responses in brain regions involved in visual processing. Furthermore, visual working memory training boosted additional activation in the precuneus, presumably reflecting mental image generation of the learned characters. We, therefore, suggest that the conjoint activity of the mid-fusiform gyrus and the precuneus after visual working memory training reflects an interaction of working memory and imagery processes with complex visual stimuli that fosters the coherent synthesis of a percept from a complex visual input in service of enhanced Chinese character learning.

Working memory capacity in preschool children contributes to the acquisition of school relevant precursor skills

The aim of the present study was to investigate whether preschool children with limitations in the visual or phonological working memory are disadvantaged in the acquisition of school relevant precursor skills at school entry. A sample of 92 children was divided into three subgroups depending on their performance in visual and phonological working memory tasks in their last year before school entry (T1). At T1 the children were tested on cognitive measures as well as quantity–number competencies and phonological awareness tasks. Shortly after school entry (T2), the precursor skills were assessed again. The findings indicate that preschool children with reduced phonological working memory capacity show weaker numerical competencies before school entry and weaker phonological awareness skills at the beginning of school compared to an unimpaired control group. On the other hand, visual working memory limitations in preschool only affect numerical competencies before and particularly after school entry.

Explaining the modality effect in multimedia learning: Is it due to a lack of temporal contiguity with written text and pictures?

The study examined whether the modality effect is caused by either high visuo-spatial load or a lack of temporal contiguity when processing written text and pictures. Students ( N = 147) viewed pictures on the development of tornados, which were accompanied by either spoken or written explanations presented simultaneously with, before, or after the pictures. For verbal recall no modality effect was observed, whereas for transfer the influence of modality varied as a function of phonological working memory capacity. For pictorial recall the results showed a modality effect that was limited to simultaneous presentation, apparently in line with the temporal contiguity explanation. However, spoken simultaneous presentations were not superior to spoken sequential presentations, which contradicts the temporal contiguity explanation for the modality effect. Rather, it seems as if learners with simultaneous presentation of written text and picture concentrated more on the text and ignored the pictures, resulting in worse pictorial recall.

Evidence for the modality independence of the genetic epistasis between the dopaminergic and cholinergic system on working memory capacity

Working memory (WM) is fractionated into systems for visuospatial and phonological information. Recently, it has been shown that the dopamine d2 receptor gene DRD2 and CHRNA4, the gene coding for the nicotinic acetylcholine receptor's alpha4 subunit, interact epistatically on visuospatial WM capacity. In the present study, we show a similar interaction on phonological WM capacity in N = 137 healthy subjects genotyped for two single nucleotide polymorphisms (DRD2 rs6277 and CHRNA4 rs1044396). Given the functional independence of the two systems we hypothesize that the genetic interaction targets the central executive which is the common control process for both systems.

Inferior Frontal Gyrus Activation Predicts Individual Differences in Perceptual Learning of Cochlear-Implant Simulations

This study investigated the neural plasticity associated with perceptual learning of a cochlear implant (CI) simulation. Normal-hearing listeners were trained with vocoded and spectrally shifted speech simulating a CI while cortical responses were measured with functional magnetic resonance imaging (fMRI). A condition in which the vocoded speech was spectrally inverted provided a control for learnability and adaptation. Behavioral measures showed considerable individual variability both in the ability to learn to understand the degraded speech, and in phonological working memory capacity. Neurally, left-lateralized regions in superior temporal sulcus and inferior frontal gyrus (IFG) were sensitive to the learnability of the simulations, but only the activity in prefrontal cortex correlated with interindividual variation in intelligibility scores and phonological working memory. A region in left angular gyrus (AG) showed an activation pattern that reflected learning over the course of the experiment, and covariation of activity in AG and IFG was modulated by the learnability of the stimuli. These results suggest that variation in listeners' ability to adjust to vocoded and spectrally shifted speech is partly reflected in differences in the recruitment of higher-level language processes in prefrontal cortex, and that this variability may further depend on functional links between the left inferior frontal gyrus and angular gyrus. Differences in the engagement of left inferior prefrontal cortex, and its covariation with posterior parietal areas, may thus underlie some of the variation in speech perception skills that have been observed in clinical populations of CI users.

Uses and interpretations of non‐word repetition tasks in children with and without specific language impairments (SLI)

The non-word repetition task (NRT) has gained wide acceptance in describing language acquisition in both children with normal language development (NL) and children with specific language impairments (SLI). This task has gained wide acceptance because it so closely matches the phonological component of word learning, and correlates with measures of phonological working memory, a deficit in which is hypothesized to underlie SLI. Recent uses of the NRT seem to accept it as a measure of phonological working memory capacity in spite of the fact that researchers have consistently acknowledged that the task taps many language processes, including speech perception, phonological encoding, phonological memory, phonological assembly and articulation. This paper reviews the literature on the use of the non-word repetition task (NRT) in children with NL and children with SLI, emphasizing the component skills necessary for successful repetition. For children with NL, discussion has focused on (1) the relationship between non-word repetition ability and vocabulary, and (2) lexical and sublexical influences on repetition accuracy. For children with SLI, discussion has focused on these factors as well, but has also considered other component skills that support non-word repetition. Researchers have examined speech perception and discrimination, phonological encoding, phonological memory, phonological assembly, motor planning, and articulation, and have found evidence that children with SLI exhibit impairments in each of these supporting skills. Because repetition accuracy depends on lexical and sublexical properties, the NRT can be used to examine the structural properties of the lexicon in both children with NL and with SLI. Further, because the task taps so many underlying skills, it is a powerful tool that can be used to identify children with language impairments.