A computerized version of the Corsi blocks task (Milner, 1971) was assessed for standard forward-recall order (Experiments 1 and 3) and for reversed-recall order (Experiments 2 and 3) either in a single-task or in a dual-task design combined with articulatory suppression, matrix-tapping, random-interval generation or fixed-interval generation as concurrent tasks during the encoding stage. Concurrent performance of the matrix-tapping task impaired memory performance for short as well as for longer block sequences. The random-interval generation task, which loads executive processes, impaired memory performance mainly at intermediate- and longer-sequence lengths, while fixed-interval generation, which is presumed to put no load on executive processing, did not show any effect. Articulatory suppression did not impair memory performance on forward-recall order, but it impaired memory for longer sequences in the backward-recall condition in Experimentt 2, but not in Experiment 3. The results are discussed within the context of the working-memory model of Baddeley and Hitch (1974

Highlights-Language switching is directly related to executive control advantages -Frequent language switchers are better at processing conflicting information -L2 proficiency plays a much smaller role 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 AbstractIn an ongoing debate, bilingual research currently discusses whether bilingualism enhances non-linguistic executive control. The goal of this study was to investigate the influence of language switching experience, rather than language proficiency, on this bilingual executive control advantage. We compared the performance of unbalanced bilinguals, balanced non-switching, and balanced switching bilinguals on two executive control tasks, i.e. a flanker and a Simon task. We found that the balanced switching bilinguals outperformed both other groups in terms of executive control performance, whereas the unbalanced and balanced non-switching bilinguals did not differ. These findings indicate that language switching experience, rather than high second-language proficiency, is the key determinant of the bilingual advantage in cognitive control processes related to interference resolution.

The present study offers an integrative account which proposes that dyslexia and its various associated cognitive impairments reflect an underlying deficit in the long-term learning of serial-order information, here operationalized as Hebb repetition learning. In non-dyslexic individuals, improved immediate serial recall is typically observed when one particular sequence of items is repeated across an experimental session, a phenomenon known as the Hebb repetition effect. Starting from the critical observation that individuals with dyslexia seem to be selectively impaired in cognitive tasks that involve processing of serial order, the present study is the first to test and confirm the hypothesis that the Hebb repetition effect is affected in dyslexia, also in non-verbal modalities. We present a theoretical framework in which the Hebb repetition effect is assumed to be a laboratory analogue of naturalistic word learning, on the basis of which we argue that dyslexia is characterized by an impairment of serial-order learning that affects language learning and processing.Keywords: dyslexia, Hebb sequence learning, serial-order information, language learning, reading, verbal short-term memory, working memory Serial-order learning in dyslexia 3 Order or dis-order? Impaired Hebb learning in dyslexiaDevelopmental dyslexia is a reading disability of neurological origin that persists throughout life despite adequate intelligence, education and socioeconomic background (Snowling, Bishop, & Stothard, 2000). It affects about 5 − 10% of the population (Shaywitz, 1996), and it has been found in many people with impressive achievements, from Leonardo Da Vinci and Albert Einstein to Agatha Christie and Walt Disney. Several decades of research have shown that dyslexia strongly impinges on cognitive functioning, even beyond reading: associated problems have been reported in sensory functioning (Stein, 2001), working memory (Smith-Spark & Fisk, 2007) and motor learning (Howard, Howard, Japikse, & Eden, 2006;Vicari, Marotta, Menghini, Molinari, & Petrosini, 2003). Because different areas of cognitive functioning are affected in dyslexia, it has proven particularly difficult to put forward a unified theoretical framework that is able to provide a satisfactory explanation for this complex picture of cognitive impairments (Ramus, Rosen, Dakin, Day, Castellote, White, & Frith, 2003;Vidyasagar & Pammer, 2010). Instead, influential accounts of dyslexia have focused on key aspects of impaired language processing, such as phonological awareness, (e.g., Vellutino, Fletcher, Snowling, & Scanlon, 2004), or on associated visual-sensory problems (e.g., the magnocellular deficit theory, Stein, 2001; but see also Vidyasagar & Pammer, 2010) and perceptual problems (e.g., the perceptual anchor theory, Ahissar, 2007), or even on motor learning dysfunctions (e.g., the automaticity/cerebellar deficit theory, Nicolson & Fawcett, 1990).The present study approaches dyslexia and its associated impairments from a new, memory-based perspective. We pu...

Several authors have hypothesized that visuo-spatial working memory is functionally analogous to verbal working memory. Irrelevant background speech impairs verbal short-term memory. We investigated whether irrelevant visual information has an analogous effect on visual short-term memory, using a dynamic visual noise (DVN) technique known to disrupt visual imagery (Quinn & McConnell, 1996b). Experiment I replicated the effect of DVN on pegword imagery. Experiments 2 and 3 showed no effect of DVN on recall of static matrix patterns, despite a significant effect of a concurrent spatial tapping task. Experiment 4 showed no effect of DVN on encoding or maintenance of arrays of matrix patterns, despite testing memory by a recognition procedure to encourage visual rather than spatial processing. Serial position curves showed a one-item recency effect typical of visual short-term memory. Experiment 5 showed no effect of DVN on short-term recognition of Chinese characters, despite effects of visual similarity and a concurrent colour memory task that confirmed visual processing of the characters. We conclude that irrelevant visual noise does not impair visual short-term memory. Visual working memory may not be functionally analogous to verbal working memory, and different cognitive processes may underlie visual short-term memory and visual imagery.

The Hebb repetition effect and naturalistic word-form learning AbstractThis study clarifies the involvement of short-and long-term memory in novel word-form learning, using the Hebb repetition paradigm. In Experiment 1, participants recalled sequences of visually presented syllables (e.g., la-va-bu-sa-fa-ra-re-si-di), with one particular (Hebb) sequence repeated on every third trial. Crucially, these Hebb sequences contained three orthographic nonword neighbours of existing Dutch base-words (e.g., lavabu -lavabo [kitchen sink]). Twenty-four hours later, the same participants performed two auditory lexicalization tests involving the actual Dutch base-words (e.g., lavabo, safari, residu). Both tests yielded slower reaction times for these Dutch base-words compared with matched control words, which reflects lexical competition between the base-words and the Hebb sequences, therefore demonstrating lexical engagement of the Hebb sequences. In Experiment 2, we subsequently used the Hebb paradigm as an analogue of word-form learning, in order to investigate whether the creation of novel lexical memories requires sleep. Whereas earlier findings indicate that overnight sleep plays a crucial role in lexical consolidation, the current results show that Hebb learning of phonological sequences creates novel word-forms representations in the mental lexicon by the mere passage of time, with sleep playing no necessary role.

The present study tests the hypothesis that a common ordering mechanism underlies both short-term serial recall of verbal materials and the acquisition of novel long-term lexical representations, using the Hebb repetition effect. In the first experiment, participants recalled visually presented nonsense syllables following a typical Hebb effect learning protocol. Replicating the Hebb repetition effect, we observed improved recall for repeated sequences of syllables. In the second experiment, the same participants performed an auditory lexical decision task, which included nonwords that were constructed from the syllables used in the first experiment. We observed inhibited rejection of nonwords that were composed of the repeated Hebb sequences, compared to nonwords that were built from nonrepeated filler sequences. This suggests that a long-term phonological lexical representation developed during Hebb learning. Accordingly, the relation between immediate serial recall and word learning is made explicit by arguing that the Hebb repetition effect is a laboratory analogue of naturalistic vocabulary acquisition.

The current study aimed to clarify the nature of the processes underlying working memory updating. In a series of four experiments using the n-back paradigm, the authors demonstrate that continuous updating of items in working memory prevents strong binding of those items to working memory, and hence leads to an increased susceptibility to proactive interference. Results of Experiments 1 and 2 show that this interference reflects a competition between a fast and automatic process that reveals the degree of familiarity of an item, and a controlled, context-sensitive recollection process that depends on the strength of bindings between the item and working memory. Experiment 3 further clarifies the origins of this interference by demonstrating that even items that are semantically related to the updated working memory contents, but that have not been maintained in working memory before, cause proactive interference during updating.Finally, the results of Experiment 4 indicate that this interference is controlled through top-down behavioral adjustments that prioritize recollection over familiarity-assessment.The implications of these findings for the construct validity of the n-back task, for the control processes involved in working memory updating, and for the concept of executive control more generally, are discussed.

The present study explored the relation between language control and nonverbal cognitive control in different bilingual populations. We compared monolinguals, Dutch-French unbalanced bilinguals, balanced bilinguals, and interpreters on the Simon task (Simon & Rudell, 1967) and the Attention Network Test (ANT; Fan, McCandliss, Sommer, Raz, & Posner, 2002). All bilingual groups showed a smaller congruency effect in the Simon task than the monolingual group. They were also faster overall in the ANT. Furthermore, interpreters outperformed unbalanced, but not balanced, bilinguals in terms of overall accuracy on both tasks. In the ANT, the error congruency effect was significantly smaller for interpreters and balanced bilinguals. Using a measure of switching fluency in language production, this study also found direct evidence for a relation between language control and executive control. This relation was only observed in balanced bilinguals, where fluent switching was correlated with the Simon effect. These findings support the existence of a bilingual advantage and also indicate that different patterns of bilingual language use modulate the nature and extent of a cognitive control advantage in multilingual populations.