Reliability of the serial reaction time task: If at first you don't succeed, try, try, try again.

Procedural memory is involved in the acquisition and control of skills and habits that underlie rule and procedural learning, including the acquisition of grammar and phonology. The serial reaction time task (SRTT), commonly used to assess procedural learning, has been shown to have poor stability (test-retest reliability). We investigated factors that may affect the stability of the SRTT in adults. Experiment 1 examined whether the similarity of sequences learned in two sessions would impact stability: test-retest correlations were low regardless of sequence similarity (r < .31). Experiment 2 added a third session to examine whether individual differences in learning would stabilise with further training. There was a small (but nonsignificant) improvement in stability for later sessions (Sessions 1 and 2: r = .42; Sessions 2 and 3: r = .60). Stability of procedural learning on the SRTT remained suboptimal in all conditions, posing a serious obstacle to the use of this task as a sensitive predictor of individual differences and ultimately theoretical advance.

The reliability of the serial reaction time task: meta-analysis of test-retest correlations.

The Serial Reaction Time task, one of the most widely used tasks to index procedural memory, has been increasingly employed in individual differences research examining the role of procedural memory in language and other cognitive abilities. Yet, despite consistently producing robust procedural learning effects at the group level (i.e. faster responses to sequenced/probable trials versus random/improbable trials), these effects have recently been found to have poor reliability. In this meta-analysis (N = 7), comprising 719 participants (M = 20.81, s.d. = 7.13), we confirm this 'reliability paradox'. The overall retest reliability of the robust procedural learning effect elicited by the SRTT was found to be well below acceptable psychometric standards (r < 0.40). However, split-half reliability within a session is better, with an overall estimate of 0.66. There were no significant effects of sampling (participants' age), methodology (e.g. number of trials, sequence type) and analytical decisions (whether all trials were included when computing the procedural learning scores; using different indexes of procedural learning). Thus, despite producing robust effects at the group-level, until we have a better understanding of the factors that improve the reliability of this task using the SRTT for individual differences research should be done with caution.

Limited Evidence of an Association Between Language, Literacy, and Procedural Learning in Typical and Atypical Development: A Meta-Analysis.

The ability to extract patterns from sensory input across time and space is thought to underlie the development and acquisition of language and literacy skills, particularly the subdomains marked by the learning of probabilistic knowledge. Thus, impairments in procedural learning are hypothesized to underlie neurodevelopmental disorders, such as dyslexia and developmental language disorder. In the present meta-analysis, comprising 2396 participants from 39 independent studies, the continuous relationship between language, literacy, and procedural learning on the Serial Reaction Time task (SRTT) was assessed across children and adults with typical development (TD), dyslexia, and Developmental Language Disorder (DLD). Despite a significant, but very small, relationship between procedural learning and overall language and literacy measures, this pattern was not observed at the group-level when examining TD, dyslexic, and DLD groups separately. Based on the procedural/declarative model, a positive relationship was expected between procedural learning and language and literacy measures for the typically developing group; however, no such relationship was observed. This was also the case for the disordered groups (ps > .05). Also counter to expectations, the magnitude of the relationship between procedural learning and grammar and phonology did not differ between TD and DLD (ps > .05), nor between the TD and dyslexic group on reading, spelling, and phonology (ps > .05). While lending little support to the procedural/declarative model, we consider that these results may be the consequence of poor psychometric properties of the SRTT as a measure of procedural learning.

Stronger Associations Between Sleep and Mental Health in Adults with Autism: A UK Biobank Study.

This study examined sleep and its cognitive and affective correlates in adults with and without autism spectrum disorder (ASD), utilizing UK Biobank data. There were no group differences in subjective sleep duration [n = 220 ASD; n = 2200 general population (GP)]. Accelerometer measures of sleep duration or nighttime activity did not differ by group, but sleep efficiency was marginally lower in ASD (n = 83 ASD; n = 824 GP). Sleep efficiency was associated with wellbeing and mental health, and pathways between accelerometer sleep measures and wellbeing and mental health were significantly stronger for adults with ASD (who also reported substantially poorer wellbeing and > 5 × likelihood of experiencing mental distress). These findings highlight the need to monitor sleep to maintain good mental health in adult ASD.

Sleep health among people with severe mental ill health during the COVID-19 pandemic: Results from a linked UK population cohort study.

Objectives: Sleep problems are a transdiagnostic feature of nearly all psychiatric conditions, and a strong risk factor for initial and recurrent episodes. However, people with severe mental ill health (SMI) are often excluded from general population surveys, and as such the extent and associates of poor sleep in this population are less well understood. This study explores sleep health in an SMI sample during the COVID-19 pandemic, using multiple regression to identify risk factors, including daily routine, wellbeing and demographics. Methods: An existing cohort of people with an SMI diagnosis were sampled. Participants were invited to complete a self-report survey about their health and the impacts of COVID-19 and associated public health measures. Sleep duration, efficiency, and quality were measured using items from the Pittsburgh Sleep Quality Index (PSQI). Results: Two hundred forty-nine adults (aged 21-84 years) completed the survey. Mean sleep duration and efficiency were similar to general population estimates, at 7 h 19 min and 78%, respectively. However, 43% reported "bad" sleep quality that was associated with being younger in age as well as disturbed routine and declined wellbeing. Indeed, 37% reported a disturbed routine during the pandemic. Conclusions: High estimates of perceived poor sleep quality in the SMI population align with previous findings. Supporting people with SMI to maintain routine regularity may work to protect sleep quality and wellbeing. Future research should more closely examine sleep health in people with SMI, using accessible and scalable measures of objective and subjective sleep, examining longitudinal trends.

Retrieval practice transfer effects for multielement event triplets.

Retrieval practice (RP) leads to improved retention relative to re-exposure and is considered a robust phenomenon when the final test conditions are identical to RP conditions. However, the extent to which RP 'transfers' to related material is less clear. Here, we tested for RP transfer effects under conditions known to induce integration of associated material at encoding, which may make transfer more likely. Participants learned multielement triplets (locations, animals and objects) and one pairwise association from each triplet was tested through RP, re-exposed, or not re-exposed (control). Two days later participants completed a final test of all pairwise associations. We found no evidence for an RP effect compared to re-exposure, but both tested/re-exposed pairs were better remembered than the not re-exposed control condition. We also found that transfer occurred from both tested to untested and re-exposed to not re-exposed pairs. Our results highlight that RP and re-exposure can boost retention for directly tested/re-exposed event pairs and associated but untested/not re-exposed event pairs, suggesting re-exposure of integrated information can be of pedagogical value. The results also question the boundary conditions for an increase in retention for RP relative to re-exposure, highlighting the need for a better theoretical understanding of RP effects.

The role of prior lexical knowledge in children's and adults' incidental word learning from illustrated stories.

Children and adults benefit from a new word's phonological neighbors during explicit vocabulary instruction, suggesting that related prior knowledge can support new learning. This study examined the influence of lexical neighborhood structure during incidental word learning-limiting opportunities for strategically engaging prior knowledge-and tested the hypothesis that prior knowledge would provide additional support during subsequent consolidation. Children aged 8-10 years (Experiment 1) and adults (Experiment 2) were presented with 15 pseudowords embedded in a spoken story with illustrations, and were then tested on their recognition and recall of the new word-forms immediately, the next day, and one week later. The pseudowords had either no, one, or many English phonological neighbors, varying the potential connections to existing knowledge. After encountering the pseudowords in this incidental training paradigm, neither children nor adults benefited from phonological neighbors in recall, and children were better at recognizing items without neighbors. The neighbor influence did not change with opportunities for consolidation in either experiment, nor did it relate to learners' existing vocabulary ability. Exploratory analyses revealed that children experienced bigger benefits from offline consolidation overall, with adults outperforming children only for many-neighbor items one week after exposure. We discuss how the neighbor benefit in word learning may be constrained by learning context, and how the enhanced benefits of offline consolidation in childhood extend to vocabulary learning in more naturalistic contexts. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Timing storytime to maximize children's ability to retain new vocabulary.

Shared storybook reading is a key aid to vocabulary acquisition during childhood. However, word learning research has tended to use unnaturalistic (explicit) training regimes. Using a storybook paradigm, we examined whether children (particularly those with weaker vocabularies) are more likely to retain new words if they learn them closer to sleep. Parents read their children (5- to 7-year-olds; N = 237) an alien adventure story that contained 12 novel words with illustrations at one of two training times: at bedtime or 3-5 h before bedtime. Using online tasks, parents tested their children's ability to recall the new words (production) and associate them with pictures (comprehension) immediately after hearing the story and again the following morning. As hypothesized, we replicated two findings. First, children showed overnight improvements in their ability to produce and comprehend new words when tested again the next day. Second, children with better existing vocabulary knowledge showed larger overnight gains in new word comprehension. Counter to expectations, overnight gains in comprehension were larger if the story was read 3-5 h before bedtime rather than at bedtime. These ecologically valid findings are consistent with theories that characterize word learning as a prolonged process supported by mechanisms such as consolidation and retrieval practice, with existing vocabulary knowledge acting as an important source of variability in retention. The findings provide preliminary evidence that encountering new words in stories later in the day (but not too close to sleep) may help to harness vocabulary growth and may be more beneficial than leaving shared storybook reading just for bedtime.

The Formation and Retrieval of Holistic Event Memories Across Development.

Event memories consist of associations between their constituent elements, leading to their holistic retrieval via the process of pattern completion. This holistic retrieval can occur, under specific conditions, when each within-event association is encoded in a separate temporal context: adults are able to integrate the information into a single coherent representation. In this study, we sought to replicate the holistic retrieval of simultaneously encoded event elements in children, and examine whether children can similarly integrate across separated encoding contexts. Children (aged 6-7 years; 9-10 years) and adults encoded two series of three-element "events" consisting of an animal, object, and location. In the simultaneous condition, they encountered all three event elements at once; in the separated condition, they encountered each pairwise association separately (animal-object, animal-location, object-location). After encoding, they were tested on the retrieval of each within-event association using a 4-alternative-forced-choice task. We inferred the presence of holistic retrieval using a measure of retrieval dependency-the statistical dependency between retrieval of within-event associations. Memory for the pairs improved across ages, but there were no developmental differences in retrieval dependency. In the simultaneous encoding condition, all three age groups showed retrieval dependency. However, counter to previous studies, retrieval dependency was not observed in any age group following separated encoding. The results from the simultaneous encoding condition support the idea that pattern completion processes are developed by early childhood. The absence of retrieval dependency in adults following separated encoding prevent conclusions regarding the developmental trajectory of mnemonic integration.

Make or break it: boundary conditions for integrating multiple elements in episodic memory.

Event memories are characterized by the holistic retrieval of their constituent elements. Studies show that memory for individual event elements (e.g. person, object and location) are statistically related to each other, and that the same associative memory structure can be formed by learning all pairwise associations across separated encoding contexts (person-object, person-location, object-location). Counter to previous studies that have shown no differences in holistic retrieval between simultaneously and separately encoded event elements, adults did not show evidence of holistic retrieval from separately encoded event elements when using a similar paradigm adapted for children (Experiment 1). We conducted a further five online experiments to explore the conditions under which holistic retrieval emerges following separated encoding of within-event associations, testing for influences of trial length (Experiment 2), the number of events learned (Experiment 3a) and stimulus presentation format (Experiments 3b, 4a, 4b). Presentation of written words was optimal for integrating elements across encoding trials, whereas the addition of spoken words disrupted integration across separately presented associations. The use of picture stimuli also produced effect sizes smaller than those of previously published research. We discuss the ways in which memory integration processes may be disrupted by these differences in presentation format. The findings have practical implications for the utility of this paradigm across research and learning contexts.

Sleep-dependent consolidation in children with comprehension and vocabulary weaknesses: it'll be alright on the night?

BACKGROUND: Vocabulary is crucial for an array of life outcomes and is frequently impaired in developmental disorders. Notably, 'poor comprehenders' (children with reading comprehension deficits but intact word reading) often have vocabulary deficits, but underlying mechanisms remain unclear. Prior research suggests intact encoding but difficulties consolidating new word knowledge. We test the hypothesis that poor comprehenders' sleep-associated vocabulary consolidation is compromised by their impoverished lexical-semantic knowledge. METHODS: Memory for new words was tracked across wake and sleep to assess encoding and consolidation in 8-to-12-year-old good and poor comprehenders. Each child participated in two sets of sessions, one beginning in the morning (AM-encoding) and the other in the evening (PM-encoding). In each case, they were taught 12 words and were trained on a spatial memory task. Memory was assessed immediately, 12- and 24-hr later via stem-completion, picture-naming, and definition tasks to probe different aspects of word knowledge. Long-term retention was assessed 1-2 months later. RESULTS: Recall of word-forms improved over sleep and postsleep wake, as measured in both stem-completion and picture-naming tasks. Counter to hypotheses, deficits for poor comprehenders were not observed in consolidation but instead were seen across measures and throughout testing, suggesting a deficit from encoding. Variability in vocabulary knowledge across the whole sample predicted sleep-associated consolidation, but only when words were learned early in the day and not when sleep followed soon after learning. CONCLUSIONS: Poor comprehenders showed weaker memory for new words than good comprehenders, but sleep-associated consolidation benefits were comparable between groups. Sleeping soon after learning had long-lasting benefits for memory and may be especially beneficial for children with weaker vocabulary. These results provide new insights into the breadth of poor comprehenders' vocabulary weaknesses, and ways in which learning might be better timed to remediate vocabulary difficulties.

Atypicalities in sleep and semantic consolidation in autism.

Sleep is known to support the neocortical consolidation of declarative memory, including the acquisition of new language. Autism spectrum disorder (ASD) is often characterized by both sleep and language learning difficulties, but few studies have explored a potential connection between the two. Here, 54 children with and without ASD (matched on age, nonverbal ability and vocabulary) were taught nine rare animal names (e.g., pipa). Memory was assessed via definitions, naming and speeded semantic decision tasks immediately after learning (pre-sleep), the next day (post-sleep, with a night of polysomnography between pre- and post-sleep tests) and roughly 1 month later (follow-up). Both groups showed comparable performance at pre-test and similar levels of overnight change on all tasks; but at follow-up children with ASD showed significantly greater forgetting of the unique features of the new animals (e.g., pipa is a flat frog). Children with ASD had significantly lower central non-rapid eye movement (NREM) sigma power. Associations between spindle properties and overnight changes in speeded semantic decisions differed by group. For the TD group, spindle duration predicted overnight changes in responses to novel animals but not familiar animals, reinforcing a role for sleep in the stabilization of new semantic knowledge. For the ASD group, sigma power and spindle duration were associated with improvements in responses to novel and particularly familiar animals, perhaps reflecting more general sleep-associated improvements in task performance. Plausibly, microstructural sleep atypicalities in children with ASD and differences in how information is prioritized for consolidation may lead to cumulative consolidation difficulties, compromising the quality of newly formed semantic representations in long-term memory.

Offline consolidation supersedes prior knowledge benefits in children's (but not adults') word learning.

Prior linguistic knowledge is proposed to support the acquisition and consolidation of new words. Adults typically have larger vocabularies to support word learning than children, but the developing brain shows enhanced neural processes that are associated with offline memory consolidation. This study investigated contributions of prior knowledge to initial word acquisition and consolidation at different points in development, by teaching children and adults novel words (e.g., ballow) that varied in the number of English word-form "neighbours" (e.g., wallow, bellow). Memory for the novel word-forms was tested immediately after training, the next day and 1 week later, to assess the time-course of prior knowledge contributions. Children aged 7-9 years (Experiments 1, 3) and adults (Experiment 2) recalled words with neighbours better than words without neighbours when tested immediately after training. However, a period of offline consolidation improved overall recall and reduced the influence of word-form neighbours on longer term memory. These offline consolidation benefits were larger in children than adults, supporting theories that children have a greater propensity for consolidating phonologically distinctive language information. Local knowledge of just a single word-form neighbour was enough to enhance learning, and this led to the individual differences in word recall that were related to adults' global vocabulary ability. The results support the proposal that the relative contributions of different learning mechanisms change across the lifespan, and highlight the importance of testing theoretical models of word learning in the context of development.

Consolidation of vocabulary is associated with sleep in typically developing children, but not in children with dyslexia.

Sleep is known to play an active role in consolidating new vocabulary in adults; however, the mechanisms by which sleep promotes vocabulary consolidation in childhood are less well understood. Furthermore, there has been no investigation into whether previously reported differences in sleep architecture might account for variability in vocabulary consolidation in children with dyslexia. Twenty-three children with dyslexia and 29 age-matched typically developing peers were exposed to 16 novel spoken words. Typically developing children showed overnight improvements in novel word recall; the size of the improvement correlated positively with slow wave activity, similar to previous findings with adults. Children with dyslexia showed poorer recall of the novel words overall, but nevertheless showed overnight improvements similar to age-matched peers. However, comparisons with younger children matched on initial levels of novel word recall pointed to reduced consolidation in dyslexics after 1 week. Crucially, there were no significant correlations between overnight consolidation and sleep parameters in the dyslexic group. This suggests a reduced role of sleep in vocabulary consolidation in dyslexia, possibly as a consequence of lower levels of learning prior to sleep, and highlights how models of sleep-associated memory consolidation can be usefully informed by data from typical and atypical development.

Letter to the Editor concerning «A systematic review of controlled trials on visual stress using intuitive overlays or colorimeter» / Carta al Editor en relación a «Revisión sistemática de ensayos controlados sobre estrés visual utilizando filtros intuitivos o colorímetro»

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A sequence learning impairment in dyslexia? It depends on the task.

Language acquisition is argued to be dependent upon an individuals' sensitivity to serial-order regularities in the environment (sequential learning), and impairments in reading and spelling in dyslexia have recently been attributed to a deficit in sequential learning. The present study examined the learning and consolidation of sequential knowledge in 30 adults with dyslexia and 29 typical adults matched on age and nonverbal ability using two tasks previously reported to be sensitive to a sequence learning deficit. Both groups showed evidence of sequential learning and consolidation on a serial response time (SRT) task (i.e., faster and more accurate responses to sequenced spatial locations than randomly ordered spatial locations during training that persisted one week later). Whilst typical adults showed evidence of sequential learning on a Hebb repetition task (i.e., more accurate serial recall of repetitive sequences of nonwords versus randomly ordered sequences), adults with dyslexia showed initial advantages for repetitive versus randomly ordered sequences in the first half of training trials, but this effect disappeared in the second half of trials. This Hebb repetition effect was positively correlated with spelling in the dyslexic group; however, there was no correlation between sequential learning on the two tasks, placing doubt over whether sequential learning in different modalities represents a single capacity. These data suggest that sequential learning difficulties in adults with dyslexia are not ubiquitous, and when present may be a consequence of task demands rather than sequence learning per se.

The effect of coloured overlays and lenses on reading: a systematic review of the literature.

PURPOSE: There are many anecdotal claims and research reports that coloured lenses and overlays improve reading performance. Here we present the results of a systematic review of this literature and examine the quality of the evidence. METHODS: We systematically reviewed the literature concerning the effect of coloured lenses or overlays on reading performance by searching the PsychInfo, Medline and Embase databases. This revealed 51 published items (containing 54 data sets). Given that different systems are in use for issuing coloured overlays or lenses, we reviewed the evidence under four separate system headings (Intuitive, Irlen, Harris/Chromagen and Other), classifying each published item using the Cochrane Risk of Bias tool. RESULTS: Although the different colour systems have been subjected to different amounts of scientific scrutiny, the results do not differ according to the system type, or whether the sample under investigation was classified as having visual stress (or a similarly defined condition), reading difficulty, or both. The majority of studies are subject to 'high' or 'uncertain' risk of bias in one or more key aspects of study design or outcome, with studies at lower risk from bias providing less support for the benefit of coloured lenses/overlays on reading ability. While many studies report improvements with coloured lenses, the effect size is generally small and/or similar to the improvement found with a placebo condition. We discuss the strengths and shortcomings of the published literature and, whilst acknowledging the difficulties associated with conducting trials of this type, offer some suggestions about how future trials might be conducted. CONCLUSIONS: Consistent with previous reviews and advice from several professional bodies, we conclude that the use of coloured lenses or overlays to ameliorate reading difficulties cannot be endorsed and that any benefits reported by individuals in clinical settings are likely to be the result of placebo, practice or Hawthorne effects.