How Time Pressure Modulates Individual Differences in the Functional Connectivity of Chunk Memory in Chess Games.

Previous studies on the chess game demonstrated that chess experts strongly rely on the activation of memory chunks to manifest accurate decision-making. Although the chunk memory might be affected by temporal constraints, it is unclear why the performance of chess experts is not significantly dropped under time pressure. In this study, our objective is to examine the variations in cognitive neural mechanisms between chess experts and novices under time pressure. The underlying cognitive neural mechanism was carefully inspected by accessing the chess game performance between 20 local experienced and 20 inexperienced chess players with 1-minute and 5-minute time constraints. In addition, functional near-infrared spectroscopy (fNIRS) recordings were carried out for each individual from the two groups while playing a 1-minute or 5-minute chess game. It was discovered that under temporal constraints, players exhibited different patterns of functional connectivity in frontal-parietal regions, suggesting that temporal stress can enhance segmentation processes in chess games. In particular, the experienced group exhibited significantly enhanced functional connectivity networks under time pressure including the dorsolateral prefrontal cortex, inferior frontal gyrus, supramarginal gyrus, and postcentral gyrus, which demonstrated the important role of the segmentation process for experienced players under time pressure. Our study found that experienced players were able to enhance recall, reorganize, and integrate chunks to improve chess performance under time pressure.

The involvement of decomposition and composition processes in restructuring during problem solving.

Decomposition of chunks has been widely accepted as a critical proxy of restructuring, but the role of composition in forming new representations has been largely neglected. This study aims to investigate the roles of both decomposition and composition processes in chunk restructuring, as well as their relationships with "aha" experiences during problem-solving. Participants were asked to move a part of a character to another character to create two new characters. Across three experiments, the characters to be decomposed or composed were varied in terms of tight or loose chunks. The results showed that decomposition or composition of tight chunks led to lower success rates, longer response times, and significantly stronger "Aha!" emotional experiences (mainly in terms of surprise and suddenness). This study provides evidence for the contribution of both decomposition and composition processes to restructuring in creative insight.

Distinct brain network organizations between club players and novices under different difficulty levels.

SIGNIFICANT: Chunk memory is one of the essential cognitive functions for high-expertise (HE) player to make efficient decisions. However, it remains unknown how the neural mechanisms of chunk memory processes mediate or alter chess players' performance when facing different opponents. AIM: This study aimed at inspecting the significant brain networks associated with chunk memory, which would vary between club players and novices. APPROACH: Functional networks and topological features of 20 club players (HE) and 20 novice players (LE) were compared at different levels of difficulty by means of functional near-infrared spectroscopy. RESULTS: Behavioral performance indicated that the club player group was unaffected by differences in difficulty. Furthermore, the club player group demonstrated functional connectivity among the dorsolateral prefrontal cortex, the frontopolar cortex, the supramarginal gyrus, and the subcentral gyrus, as well as higher clustering coefficients and lower path lengths in the high-difficulty task. CONCLUSIONS: The club player group illustrated significant frontal-parietal functional connectivity patterns and topological characteristics, suggesting enhanced chunking processes for improved chess performance.

Funny? Think About It! Selective effect of cognitive mechanisms of humour on insight problems.

The present study aims to elucidate whether insight problem solving could be facilitated by the cognitive component of humour. The authors take interest in whether the logical mechanisms of humour can affect how fast insight problems are solved. To that end, the authors conducted two experiments where participants solved insight problems after watching visual humorous stimuli such as videos and slideshows. The first experiment demonstrated the overall impact of facilitation by humour on insight problem solving; however, it did not show any difference in how particular logical mechanisms of humour affect the solution time of insight problems. The second experiment showed that the cognitive component of humour could selectively affect insight problems whose difficulty stems from different sources. These results suggest that the cognitive component of humour, when operationalised as logical mechanisms and schema switching, contributes to solving insight problems.

Potential of fluorescence fingerprints for fish meat authentication: Differences in freshness evaluation in white and dark meat at frozen state.

As dark meat has a faster deterioration rate and its unintentional mixing occurs during processing, it is crucial to know the status and freshness indicators of dark meat to ensure fishery product quality. In this method, fluorescence fingerprints (FFs) was applied as a rapid and noninvasive quality authentication method to determine differences between white and dark meat in the evaluation of freshness indicators at frozen state. Spotted mackerel (Scomber australasicus) fish chunks with different postmortem conditions (0-40 h ice stored) were obtained and frozen. A new generation of fluorescence spectrophotometer (F-7100) was used to acquire FFs of the frozen fish chunks (containing white and dark meat). Adenosine triphosphate metabolites and pH were determined in both white and dark meat using their relevant biochemical methods. Higher K-values in dark meat might be attributed to a higher accumulation rate of inosine (HxR) in dark meat than in white meat. The pH decrease rate in white meat was higher than that in dark meat during postmortem ice storage periods of fish. Principal component analysis of FFs spectra demonstrated clear discrimination (PC1 + PC2 = 91.7%) between white and dark meat of frozen fish due to the influence of freshness parameters based on the fluorescence features of fish meat. Furthermore, partial least squares regression validation models revealed that freshness indicators of white meat could be predicted more accurately at the frozen state than those of dark meat. This method could be applied during the processing of fishery products, thereby facilitating quality control activities and making it a promising authentication tool for the fisheries industries.

The orthodontist: such a common and complex expert / L'orthodontiste : un expert si commun, si complexe

Introduction: Considered from the perspective of the finesse and skill they require of those who practice them, each of the existing trades has its own specificity. However, by referring to literature on expertise and talent7, we realize to what extent the patterns of the acquisition of expertise and its implementation can have invariants among the different trades. Methods: Human expertise has been studied in depth, among others, by cognitive sciences, psychology and neurosciences. After exposing the notions of domain of expertise, perceptual-cognitive and sensory-motor competence, the neurobiological and cognitive mechanisms of expertise demonstrating the importance of long-term memory in the acquisition of expertise, for example, by reference to the concept of chunking. Results: We will seek to determine the characteristics of the orthodontist as an expert, the implications of this quality for the expert's training process, the importance of clinical experience, the extent to which the expert can trust his/her intuition (clinical sense) in his/her daily practice and the paradigm shift constituted by the digital transition, which requires new expertise in the field of developing spatial mental models of 3D structures.

Introduction: Considérés sous l'angle de la finesse et de l'habileté qu'ils exigent de ceux qui les pratiquent, les différents métiers ont chacun leur spécificité. Cependant, en se référant à la bibliographie existant sur le talent et sur l'expertise, on se rend compte à quel point les schémas de l'acquisition de l'expertise et de sa mise en œuvre peuvent avoir des invariants dans les différents corps de métiers. Méthodes: L'expertise humaine est un sujet étudié en profondeur, entre autres, par les sciences cognitives, la psychologie et les neurosciences. Après avoir exposé les domaines d'expertise (expertise perceptuelle, expertise cognitive et expertise sensori-motrice), les mécanismes neurobiologiques et cognitifs de l'expertise démontrant l'importance de la mémoire à long terme (MLT) dans l'acquisition de l'expertise, par exemple, à travers le concept de chunking seront abordés. Résultats: Nous avons déterminé les caractéristiques de l'expert qu'est l'orthodontiste, ce que sa qualité d'expert implique dans sa formation, la portée de son expérience clinique, la mesure dans laquelle il peut faire confiance à son intuition (le fameux « sens clinique ¼) dans sa pratique quotidienne et le changement de paradigme que représente la transition numérique, laquelle entraîne de nouveaux types d'expertise dans le développement des modèles mentaux spatiaux de la structure en 3D. Ce changement de paradigme affecte également la matrice de prise de décision clinique du praticien.

Chunks, pauses, and holistic processing in Mandarin spontaneous speech.

Chunks are multiword sequences with independent meaning and function, or formulaic based on the intuition of native speakers, hypothesized to be holistically restored and retrieved in the mental lexicon. Previous studies suggest that pauses and intonational boundaries tend to occur at the boundaries of chunks, but less discussion was made on the influence of chunk categories over mental processing and on pause placement associated with intonational continuity. This study adopted spontaneous monologs of Mandarin natives in formal and informal settings. It examined the co-occurrence of chunks and pause-defined processing units and pause placement around chunks to explore to what extent chunks are holistically processed. The results showed that Mandarin chunks were likely to be situated within a single processing unit, indicating chunks as smaller units than processing units in spontaneous speech. Major chunk categories exhibited significantly different patterns in co-occurring with processing units, indicating the influence of chunk properties on the mental processing of chunks. In addition, chunks tended to be fluently processed in spontaneous speech production as fewer hesitations occurred before and during chunk production. Major chunk categories shared a similar threshold in encountering hesitations before chunk production and differed significantly in hesitation distribution during chunk production. Hesitations in the middle of chunks were more likely to be situated within intonation units compared to those before chunk production. Speakers' effort to maintain the intonational continuity of chunks when they encounter processing difficulties reveals the mental reality of the holistic nature of chunks. Furthermore, the co-occurrence of chunks and processing units differed significantly between the formal and informal speech genres, indicating genre influence on the mental processing of chunks. Altogether, the findings of this study have provided implications for theories on chunks and the syntactic-prosody interface and contributed to implications for the design of Mandarin instructions and teaching.

An overlooked source of nanosized lead particles in the atmosphere: Residential honeycomb briquette combustion.

Atmospheric lead (Pb) pollution has attracted long-term and widespread concerns due to its high toxicity. The definite source identification of atmospheric Pb is the key step to mitigate this pollution. Here, we first report an overlooked source of atmospheric nanosized Pb particles using transmission electron microscopy and bulk sample analyses, finding that residential honeycomb briquette combustion emits large numbers of nanosized Pb-rich particles. We found that 33.7 ± 19.9 % of primary particles by number from residential honeycomb briquette combustion contains the crystalline Pb particles. These Pb-rich particles range in size from 14 to 956 nm with a mean diameter of 117 nm. Compared with raw coal chunks, honeycomb briquette combustion could emit less carbonaceous particles, but largely increase nanosized Pb particle emissions. This result is attributed to two key factors: (1) higher Pb content in honeycomb briquette (63.6 µg g-1) than that in coal chunk (8.5 µg g-1), and (2) higher Pb release rate for honeycomb briquette (62.3 %) caused by honeycomb structure than that for coal chunk (20.1 %). This study highlights that atmospheric and health implications of high emissions of toxic nanosized Pb from honeycomb briquette should be paid more attention in future research on ambient and indoor airs.

Delta-band neural activity primarily tracks sentences instead of semantic properties of words.

Human language is generally combinatorial: Words are combined into sentences to flexibly convey meaning. How the brain represents sentences, however, remains debated. Recently, it has been shown that delta-band cortical activity correlates with the sentential structure of speech. It remains debated, however, whether delta-band cortical tracking of sentences truly reflects mental representations of sentences or is caused by neural encoding of semantic properties of individual words. The current study investigates whether delta-band neural tracking of speech can be explained by semantic properties of individual words. Cortical activity is recorded using electroencephalography (EEG) when participants listen to sentences repeating at 1 Hz and word lists. The semantic properties of individual words, simulated using a word2vec model, predict a stronger 1 Hz response to word lists than to sentences. When listeners perform a word-monitoring task that does not require sentential processing, the 1 Hz response to word lists, however, is much weaker than the 1 Hz response to sentences, contradicting the prediction of the lexical semantics model. When listeners are explicitly asked to parse word lists into multi-word chunks, however, cortical activity can reliably track the multi-word chunks. Taken together, these results suggest that delta-band neural responses to speech cannot be fully explained by the semantic properties of single words and are potentially related to the neural representation of multi-word chunks.

Fine-Scale Genetic Structure and Natural Selection Signatures of Southwestern Hans Inferred From Patterns of Genome-Wide Allele, Haplotype, and Haplogroup Lineages.

The evolutionary and admixture history of Han Chinese have been widely discussed via traditional autosomal and uniparental genetic markers [e.g., short tandem repeats, low-density single nucleotide polymorphisms). However, their fine-scale genetic landscapes (admixture scenarios and natural selection signatures) based on the high-density allele/haplotype sharing patterns have not been deeply characterized. Here, we collected and generated genome-wide data of 50 Han Chinese individuals from four populations in Guizhou Province, one of the most ethnolinguistically diverse regions, and merged it with over 3,000 publicly available modern and ancient Eurasians to describe the genetic origin and population admixture history of Guizhou Hans and their neighbors. PCA and ADMIXTURE results showed that the studied four populations were homogeneous and grouped closely to central East Asians. Genetic homogeneity within Guizhou populations was further confirmed via the observed strong genetic affinity with inland Hmong-Mien people through the observed genetic clade in Fst and outgroup f 3 /f 4-statistics. qpGraph-based phylogenies and f 4-based demographic models illuminated that Guizhou Hans were well fitted via the admixture of ancient Yellow River Millet farmers related to Lajia people and southern Yangtze River farmers related to Hanben people. Further ChromoPainter-based chromosome painting profiles and GLOBETROTTER-based admixture signatures confirmed the two best source matches for southwestern Hans, respectively, from northern Shaanxi Hans and southern indigenes with variable mixture proportions in the historical period. Further three-way admixture models revealed larger genetic contributions from coastal southern East Asians into Guizhou Hans compared with the proposed inland ancient source from mainland Southeast Asia. We also identified candidate loci (e.g., MTUS2, NOTCH4, EDAR, ADH1B, and ABCG2) with strong natural selection signatures in Guizhou Hans via iHS, nSL, and ihh, which were associated with the susceptibility of the multiple complex diseases, morphology formation, alcohol and lipid metabolism. Generally, we provided a case and ideal strategy to reconstruct the detailed demographic evolutionary history of Guizhou Hans, which provided new insights into the fine-scale genomic formation of one ethnolinguistically specific targeted population from the comprehensive perspectives of the shared unlinked alleles, linked haplotypes, and paternal and maternal lineages.

Fried sweetpotato user preferences identified in Nigeria and Ghana and implications for trait evaluation.

Fried sweetpotato quality is important for variety adoption in West Africa. To inform breeding efforts, the study developed a product profile for sweetpotato chunk fries using mixed qualitative and quantitative methods. Root characteristics, processing attributes, in-mouth attributes and appearance of fried product were critical to final product quality. Raw roots should be hard, have smooth skin and no off-odours. Peeled roots should be hard to slice and not sticky. Stickiness and moist surface indicate high moisture content, associated with excessive oil absorption during frying. Hard to slice roots connote high dry matter. Fried product should be crisp, slightly sugary and mealy, have a uniform colour with brown tint and not be soggy. Crispness, mealiness and short frying time with limited oil absorption may be functions of starch. Understanding starch characteristics and other attributes that contribute to quality fried sweetpotato is critical for breeding sweetpotato genotypes with superior quality for frying.

Left-hemispheric predominance on appropriateness evaluation of restructuring during chunk decomposition problem solving.

Restructuring refers to achieving satisfactory solutions by breaking obstacles or forming novel associations in problem-solving. One critical question arises regarding how an appropriate solution is processed in our brain during the restructuring of problem representations. This study aims to explore the electrophysiological correlates of appropriateness evaluation of restructuring by employing a chunk decomposition task. During loose or tight chunk decomposition, participants needed to assess whether they could get a valid solution after probe removal from a source character chunk. As reflected by the late positive complex, the processing of appropriateness exhibited the greatest effect (appropriate vs. inappropriate) in left parietal regions for tight chunk decomposition, but exhibited insignificant differences across most brain regions for loose chunk decomposition. This study provides the first primary electrophysiological evidence that both hemispheres contribute to and the left hemisphere plays a predominant role in evaluating the appropriateness of restructuring in problem solving.

Common and specific neural correlates underlying insight and ordinary problem solving.

Previous studies have investigated the cognitive and neural mechanisms underlying insight problem solving (INPS). However, it is still unclear which mechanisms are common to both INPS and ordinary problem solving (ORPS), and which are distinctly involved in only one of these processes. In this study, we selected two types of Chinese character chunk decompositions, ordinary Chinese character chunk decomposition (OCD) and creative Chinese character chunk decomposition (CCD), as representatives of ORPS and INPS, respectively. By using functional magnetic resonance imaging (fMRI) to record brain activations when subjects executed OCD or CCD operations, we found that both ORPS and INPS resulted in significant activations in the widespread frontoparietal cognitive control network, including the middle frontal gyrus, inferior frontal gyrus, and inferior parietal lobe. Furthermore, compared with ORPS, INPS led to greater activations in higher-level brain regions related to symbolic processing in the default mode network, including the anterior cingulate cortex, superior temporal gyrus, angular gyrus, and precuneus. Conversely, ORPS induced greater activations than INPS in more posterior brain regions related to visuospatial attention and visual perception, such as the inferior temporal gyrus, hippocampus, and middle occipital gyrus/superior parietal gyrus/fusiform gyrus. In addition, an ROI analysis corroborated the neural commonalities and differences between ORPS and INPS. These findings provide new evidence that ORPS and INPS rely on common as well as distinct cognitive processes and cortical mechanisms.

The angrier or the happier the more creative? The impact of anger and joy induction on creative problem-solving and divergent thinking.

In contrast to the conventional reasoning process that relies heavily on cognitive control, an individual's creativity may show an increasing trend when the cognitive control function is suppressed. A typical situation in which this occurs is low cognitive inhibition triggered by strong anger. In studies of the influence of anger on creativity, the creative tasks used were mostly divergent-thinking tasks, and few studies have compared the impact of anger and joy on general thinking and creative thinking directly. In addition to using an Alternative-Uses Task (AUT) that reflects divergent thinking, this study also adopted the matching routine and novel chunk-decomposition tasks to evaluate general and novel problem-solving, respectively. We also focused on the impact of angry and joy moods on creative tasks, comparing them with a control condition of neutral mood. The results revealed that the induction of an anger emotion promotes an individual's divergent thinking more than that of a joy emotion, and that both anger and joy are effective ways for creative problem-solving. Furthermore, anger reduced the reaction time while joy increased the accuracy rate to facilitate the creative problem-solving.

The late parietal event-related potential component is hierarchically sensitive to chunk tightness during chunk decomposition.

The current study analyzed event-related potentials (ERPs) associated with visuo-spatial transformation in order to examine how "chunk tightness" affects the difficulty of chunk decomposition problems. Participants completed a Chinese character decomposition task in three conditions according to the tightness of the to-be-decomposed chunk (tight vs. medium vs. loose). Behavioral data showed that performance became worse (longer reaction time, lower accuracy) as chunk tightness increased. ERP data showed that, as chunk tightness increased, the LPC exhibited a significant decrease at posterior electrode sites. The results indicate that chunk tightness might exert its primary effect on chunk decomposition difficulty by increasing the difficulty of visuo-spatial transformation, a process linked to the parietal LPC.

Stimulus complexity and chunk tightness interact to impede perceptual restructuring during problem solving.

The mutual influence of stimulus complexity and chunk tightness on perceptual restructuring was examined using a chunk decomposition task (CDT). Participants attempted to remove components of Chinese characters in order to produce new, valid characters. Participants had their electroencephalogram recorded while completing a CDT in conditions of low or high stimulus complexity, crossed with two levels of chunk tightness. Tight chunks overlapped spatially whereas loose chunks did not. Both increasing chunk tightness and increasing stimulus complexity impaired performance (lower accuracy, longer reaction times), and these factors interacted such that highly complex, tight chunks produced the worst performance. These factors also had interacting effects on the late positive complex (LPC). The LPC amplitude was reduced by increasing chunk tightness, but this effect was attenuated for highly complex stimuli. These results suggest that though chunk tightness and stimulus complexity impair performance in the CDT, they have dissociable neural underpinnings.

Surface features can deeply affect artificial grammar learning.

Three experiments explored the extent to which surface features explain discrimination between grammatical and non-grammatical strings in artificial grammar learning (AGL). Experiment 1 replicated Knowlton and Squire's (1996) paradigm using either letter strings as in the original study, or an analogous set of color strings to further explore if learning was affected by type of stimuli. Learning arose only with letter strings, but the results were mostly due to the discrimination of non-grammatical strings containing highly salient illegal features. Experiments 2 and 3 tested a new grammar devised to control for those features. Experiment 2 showed reduced grammar learning effects, and again only for letter materials. Experiment 3 explored the effect of additional practice with letter stimuli, and found increased learning only in the spaced practice condition, though additional practice also produced more explicit knowledge. These findings call for further research on the boundary conditions of learning in AGL paradigms.

Focused ion beam preparation of microbeams for in situ mechanical analysis of electroplated nanotwinned copper with probe type indenters.

A site-specific xenon plasma focused ion beam preparation technique for microcantilever samples (1-20 µm width and 1:10 aspect ratio) is presented. The novelty of the methodology is the use of a chunk lift-out onto a clean silicon wafer to facilitate easy access of a low-cost probe type indenter which provides bending force measurement. The lift-out method allows sufficient room for the indenter and a line of sight for the electron beam to enable displacement measurement. An electroplated nanotwinned copper (NTC) was cut to a 3 × 3 × 25 µm microbeam and in situ mechanically tested using the developed technique. It demonstrated measured values of Youngs modulus of 78.7 ± 11 GPa and flow stress of 0.80 ± 0.05 GPa, which is within the ranges reported in the literature. LAY DESCRIPTION: In this paper a site specific method is present for making particularly small mechanical tests samples, of the order of 100th the size of a human hair. These small samples can then be used to determine the mechanical properties of the bulk material. Copper with a nano twinned grain structure is used as a test medium. Ion milling was used to cut the sample to shape and a micro probe was used for mechanical testing. Ion milling can cut away very small volumes of material as it accelerates ions at the surface of the sample, atomically machining the sample. Micro probes are a cost-effective small-scale load measurement devices, however, they require a large area for accessing the sample. The indenter requirements are a problem when making you samples with ion milling as ion millers are best at making small cuts. Our aim was to design a cutting strategy which reduces the amount of cutting required while allowing samples to be fabricated anywhere on the sample. We used a chunk lift out technique to remove a piece of material which is then welded to a wafer of silicon this gives sufficient space around the sample for ion milling and testing. The additional space allowed easy access for the probe. A 3 × 3 × 10 µm micro cantilever beam was cut out from copper, this beam was then bent. The force from bending and distance bent was measured and converted into Youngs modulus which is a measure of flexibility. The modulus value measured was comparable to the values reported in other papers.

Neural adaptation and cognitive inflexibility in repeated problem-solving behaviors.

Repeated stimulus processing is often associated with a reduction in neural activity, known as neural adaptation. Therefore, people are more sensitive to novelty detection but likely lose flexibility in subsequent novelty processing after detection. To demonstrate the dynamic changes in neural adaption in repeated problem-solving behaviors and test its negative influence on subsequent nonrepetitive problem-solving behaviors, we adopted a Chinese character decomposition task in this fMRI study. Participants were asked to repeatedly perform 3-5 practice problems that could be solved by the same loose chunk decomposition (LCD) solution followed by a test problem that could be solved by a tight chunk decomposition (TCD) solution in the enhanced-set condition. The practice problem gradually elicited lower percent signal changes within the cuneus, superior parietal lobule (SPL), inferior frontal gyrus (IFG) and medial prefrontal cortex (mPFC) in serial positions -1, -2 and -3 of a set, implying that neural adaptation occurred in repeated practice. Both the test problem and the practice problem that following it recruited greater activation of the SPL and IFG in the enhanced-set condition than in the base-set condition when the practice problem and test problem alternately appeared, implying that the task switching cost from a more dominant task to a less dominant task and vice versa was increased after neural adaptation occurred. In other words, repeatedly solving a set of similar problems with the same solution likely leads to neural adaptation and cognitive inflexibility, which in turn have an undifferentiated impact on task switching. This finding expands existing knowledge about the neurocognitive mechanism underlying the formation of the mental set and sheds light on the influence of neural adaptation on subsequent processing.

Identification and transformation difficulty in problem solving: Electrophysiological evidence from chunk decomposition.

A wealth of studies have investigated how to overcome experience-based constraints in creative problem solving. One such experience-based constraint is the tendency for people to view tightly organized visual stimuli as single, unified percepts, even when decomposition of those stimuli into component parts (termed chunk decomposition) would facilitate problem solving. The current study investigates the neural underpinnings of chunk decomposition in creative problem solving by analyzing event-related potentials. In two experiments, participants decomposed Chinese characters into the character's component elements and then used the base elements to form a new valid character. The action could require decomposing a "tight" chunk, meaning that the component elements intersected spatially, or a "loose" chunk, in which the component elements did not overlap in space. Behaviorally, individuals made more errors and responded slower to trials involving tight chunks relative to loose chunks. Analysis of the ERPs revealed that relative to loose chunks, the electrophysiological response to tight chunks contained an increased N2, an increased N400, and a decreased late positive complex. Taken together, these results suggest that chunk tightness is a principle determinant of the difficulty of chunk decomposition, and that chunk tightness provokes neural conflict and semantic violations, factors known to influence the N2 and N400 ERP components.