Linking L2 proficiency and patterns of functional connectivity during L1 word retrieval.

Second language (L2) learners differ greatly in language proficiency, which is partially explained by variability in native language (L1) skills. The present fMRI study explored the neural underpinnings of the L1-L2 link. Twenty L2 learners completed a tip-of-the-tongue (TOT) task that required retrieving words in L1. Low-proficiency L2 learners showed greater functional connectivity for correct and TOT responses between the left inferior frontal gyrus and right-sided homologues of the temporoparietal regions that support phonological processing (e.g., supramarginal gyrus), possibly reflecting difficulty with phonological retrieval. High-proficiency L2 learners showed greater connectivity for erroneous responses (TOT in particular) between the left inferior frontal gyrus and regions of left medial temporal lobe (e.g., hippocampus), associated with implicit learning processes. The difference between low- and high-proficiency L2 learners in functional connectivity, which is evident even during L1 processing, may affect L2 learning processes and outcomes.

Spontaneous cognition and its relationship to human creativity: A functional connectivity study involving a chain free association task.

Resting-state functional connectivity (RSFC) between various brain regions is thought to be associated with creative abilities. Extensive research correlating RSFC with performance on creativity tasks has revealed some of the RSFC patterns characterizing 'the creative brain'. Yet, our understanding of the neurocognitive processes underlying creative thinking still remains limited. This limitation results, in part, from the fact that standard creativity tasks used in these studies do not distinguish between the different modes of cognitive processing that are critical in creative cognition (e.g., spontaneous cognition vs. controlled cognition). In the present fMRI research we address this limitation by using a chain free association task â€‹- â€‹a task that we have recently refined and validated for the purpose of isolating measures of spontaneous cognition that are relevant for creative thinking (referred to as associative fluency and associative flexibility). In our study, 27 female participants completed standardized creativity tasks, a chain free association task, and a fMRI scan in which RSFC was measured. Our results indicate that higher scores on associative fluency are associated with stronger positive RSFC within the default mode network (DMN; i.e., between DMN regions). Critically, we provide evidence that the previously-identified relationship between performance on creativity tasks and connectivity within the DMN is partially mediated by associative fluency. Thus, our observations suggest that the heightened DMN connectivity observed in 'the creative brain' can be explained, at least to some extent, by spontaneous cognition. Overall, our study identifies unique RSFC patterns that are related specifically to spontaneous cognitive processes involved in creative ideation, thus shedding new light on mechanisms of creative processing.

A Semantic Network Cartography of the Creative Mind.

The role of semantic memory in creativity is theoretically assumed, but far from understood. In recent years, computational network science tools have been applied to investigate this role. These studies shed unique quantitative insights on the role of semantic memory structure in creativity, via measures of connectivity, distance, and structure.

Metaphor Comprehension in Low and High Creative Individuals.

The comprehension of metaphors involves the ability to activate a broader, more flexible set of semantic associations in order to integrate the meanings of the weakly related parts of the metaphor into a meaningful linguistic expression. Previous findings point to a relation between levels of creativity and efficiency in processing metaphoric expressions, as measured by reaction times (RTs) and error rates. Furthermore, recent studies have found that more creative individuals exhibit a relatively more flexible semantic memory structure compared to less creative individuals, which may facilitate their comprehension of novel metaphors. In the present study, lower and higher creative individuals performed a semantic relatedness judgment task on word pairs. These word pairs comprised four types of semantic relations: novel metaphors, conventional metaphors, literal word pairs, and meaningless word pairs. We hypothesized that the two groups will perform similarly in comprehending the literal, unrelated, and the conventional metaphoric word pairs. However, with respect to novel metaphors, we predicted that higher creative individuals will demonstrate better performance compared to lower creative individuals, as indicated by smaller RTs and more accurate responses. Our main finding shows that higher creative individuals were faster in comprehending both types of metaphors, conventional and novel, compared to lower creative individuals. Furthermore, higher creative individuals were significantly more accurate than lower creative individual only in comprehending novel metaphors. The findings are discussed in light of previous findings regarding the relation between metaphor comprehension, semantic memory, and creativity.

The role of psychological distancing in appreciation of art: Can native versus foreign language context affect responses to abstract and representational paintings?

Our work examines the role of psychological distancing in responses to art. We argued that the context of a foreign (vs native) language may distance the individual away from the pragmatic everyday perception style and enhance appreciation of paintings. We established the distinction between the sets of abstract and representational paintings in terms of perceptual-cognitive features and affective responses (Study 1). Then, we examined the influence of language context on appreciation of paintings. When examined separately, abstract paintings were better appreciated within a foreign (than native) language context (Study 2a), whereas appreciation of representational paintings was not significantly enhanced by a foreign language (Study 2b). The combined analysis of Studies 2a and 2b suggests, however, that distance induced by the foreign language similarly enhances appreciation of abstract and representational art.

Chain free association, creativity, and the default mode network.

Research on creativity shows that creative thinking entails both executive (controlled) and associative (spontaneous) processes. Yet standard creativity tasks cannot reliably isolate these two types of cognitive processes, making it difficult to understand the relation between the two and the roles of their corresponding brain networks in creative cognition. In this study we used a behavioral and neuroimaging approach in an effort to establish chain free association (FA) tasks as a relevant method for directly investigating spontaneous associative thinking and its role in creative cognition. We further examined the relation between performance on such tasks and intelligence. Participants completed common creativity tasks and then underwent fMRI scanning while producing FA chains. Instructions to participants that emphasized the spontaneous nature of the task, coupled with proper control conditions that were balanced for difficulty, enabled us to uncover spontaneous (as opposed to controlled) processes. To examine whether behavioral measures that can be derived from FA chains (associative fluency, associative flexibility and semantic remoteness between associations) are indicative of unconstrained spontaneous associative processing and are related to different aspects of verbal creativity and intelligence, scores on these measures were correlated with scores on creativity tasks and on an intelligence task, and with brain activity. We found that: (1) the Default Mode Network (DMN), a network involved in self-generated and internally-directed thought, was more involved in chain FA than in other tasks expected to reflect more controlled forms of internally-directed thought, suggesting that the DMN involvement might be related to the unconstrained spontaneous nature of chain FA. Higher involvement of the left IFG, SFG, MFG under chain FA was also revealed; (2) higher scores on different behavioral measures from FA chains were related to higher activation of the DMN and to reduced activation of the left IFG, a major node in the executive function network; (3) behavioral measures from FA chains were correlated with different aspects of creative performance but not with intelligence. Taken together, these findings lend support to the hypothesis that chain FA involves associative spontaneous thinking. They further suggest that behavioral measures derived from chain FA could indicate patterns of unconstrained associative thinking, related to reduced cognitive control, that are relevant for creative ideation, and might be able to serve as a measure of these patterns.

Flexibility of thought in high creative individuals represented by percolation analysis.

Flexibility of thought is theorized to play a critical role in the ability of high creative individuals to generate novel and innovative ideas. However, this has been examined only through indirect behavioral measures. Here we use network percolation analysis (removal of links in a network whose strength is below an increasing threshold) to computationally examine the robustness of the semantic memory networks of low and high creative individuals. Robustness of a network indicates its flexibility and thus can be used to quantify flexibility of thought as related to creativity. This is based on the assumption that the higher the robustness of the semantic network, the higher its flexibility. Our analysis reveals that the semantic network of high creative individuals is more robust to network percolation compared with the network of low creative individuals and that this higher robustness is related to differences in the structure of the networks. Specifically, we find that this higher robustness is related to stronger links connecting between different components of similar semantic words in the network, which may also help to facilitate spread of activation over their network. Thus, we directly and quantitatively examine the relation between flexibility of thought and creative ability. Our findings support the associative theory of creativity, which posits that high creative ability is related to a flexible structure of semantic memory. Finally, this approach may have further implications, by enabling a quantitative examination of flexibility of thought, in both healthy and clinical populations.

The semantic distance task: Quantifying semantic distance with semantic network path length.

Semantic distance is a determining factor in cognitive processes, such as semantic priming, operating upon semantic memory. The main computational approach to compute semantic distance is through latent semantic analysis (LSA). However, objections have been raised against this approach, mainly in its failure at predicting semantic priming. We propose a novel approach to computing semantic distance, based on network science methodology. Path length in a semantic network represents the amount of steps needed to traverse from 1 word in the network to the other. We examine whether path length can be used as a measure of semantic distance, by investigating how path length affect performance in a semantic relatedness judgment task and recall from memory. Our results show a differential effect on performance: Up to 4 steps separating between word-pairs, participants exhibit an increase in reaction time (RT) and decrease in the percentage of word-pairs judged as related. From 4 steps onward, participants exhibit a significant decrease in RT and the word-pairs are dominantly judged as unrelated. Furthermore, we show that as path length between word-pairs increases, success in free- and cued-recall decreases. Finally, we demonstrate how our measure outperforms computational methods measuring semantic distance (LSA and positive pointwise mutual information) in predicting participants RT and subjective judgments of semantic strength. Thus, we provide a computational alternative to computing semantic distance. Furthermore, this approach addresses key issues in cognitive theory, namely the breadth of the spreading activation process and the effect of semantic distance on memory retrieval. (PsycINFO Database Record

When pumpkin is closer to onion than to squash: The structure of the second language lexicon.

The current research investigated the organization of the second language mental lexicon. Twenty-seven English-Hebrew bilingual speakers (who spoke Hebrew as their second language) completed a semantic fluency task in each of their languages, and 24 native Hebrew speakers completed the task in Hebrew. Responses were compared within and across groups, using computational tools. The analyses indicated that the lexical network of the second language displayed greater local connectivity and less modular community structure than the network in the native language, both in the entire sample and in a sub-sample of bilinguals whose Hebrew vocabulary was matched to that of the native Hebrew speakers. These findings suggest that the lexical network of the second language is not as well-organized as is the network of the first language, even in highly proficient bilinguals. The structural characteristics of the second language lexicon might be affected by factors related to language learning history, including age of acquisition and language use.

The Hyper-Modular Associative Mind: A Computational Analysis of Associative Responses of Persons with Asperger Syndrome.

Rigidity of thought is considered a main characteristic of persons with Asperger syndrome (AS). This rigidity may explain the poor comprehension of unusual semantic relations, frequently exhibited by persons with AS. Research indicates that such deficiency is related to altered mental lexicon organization, but has never been directly examined. The present study used computational network science tools to compare the mental lexicon structure of persons with AS and matched controls. Persons with AS and matched controls generated free associations, and network tools were used to extract and compare the mental lexicon structure of the two groups. The analysis revealed that persons with AS exhibit a hyper-modular semantic organization: their mental lexicon is more compartmentalized compared to matched controls. We argue that this hyper-modularity may be related to the rigidity of thought which characterizes persons with AS and discuss the clinical and more general cognitive implications of our findings.

Processing of unconventional stimuli requires the recruitment of the non-specialized hemisphere.

In the present study we investigate hemispheric processing of conventional and unconventional visual stimuli in the context of visual and verbal creative ability. In Experiment 1, we studied two unconventional visual recognition tasks-Mooney face and objects' silhouette recognition-and found a significant relationship between measures of verbal creativity and unconventional face recognition. In Experiment 2 we used the split visual field (SVF) paradigm to investigate hemispheric processing of conventional and unconventional faces and its relation to verbal and visual characteristics of creativity. Results showed that while conventional faces were better processed by the specialized right hemisphere (RH), unconventional faces were better processed by the non-specialized left hemisphere (LH). In addition, only unconventional face processing by the non-specialized LH was related to verbal and visual measures of creative ability. Our findings demonstrate the role of the non-specialized hemisphere in processing unconventional stimuli and how it relates to creativity.

Magnetoencephalographic evidence of early right hemisphere overactivation during metaphor comprehension in schizophrenia.

Whereas language processing in neurotypical brains is left lateralized, individuals with schizophrenia (SZ) display a bilateral or reversed pattern of lateralization. We used MEG to investigate the implications of this atypicality on fine (left hemisphere) versus coarse (right hemisphere) semantic processing. Ten SZ and 14 controls were presented with fine (conventional metaphor, literal, and unrelated expressions) and coarse (novel metaphor) linguistic stimuli. Results showed greater activation of the right hemisphere for novel metaphors and greater bilateral activation for unrelated expressions at the M170 window in SZ. Moreover, at the M350, SZ showed reduced bilateral activation. We conclude that SZ are overreliant on early-stage coarse semantic processing. As a result, they jump too quickly to remote conclusions, with limited control over the meanings they form. This may explain one of the core symptoms of the disorder-loose associations.

Critical tipping point distinguishing two types of transitions in modular network structures.

Modularity is a key organizing principle in real-world large-scale complex networks. The relatively sparse interactions between modules are critical to the functionality of the system and are often the first to fail. We model such failures as site percolation targeting interconnected nodes, those connecting between modules. We find, using percolation theory and simulations, that they lead to a "tipping point" between two distinct regimes. In one regime, removal of interconnected nodes fragments the modules internally and causes the system to collapse. In contrast, in the other regime, while only attacking a small fraction of nodes, the modules remain but become disconnected, breaking the entire system. We show that networks with broader degree distribution might be highly vulnerable to such attacks since only few nodes are needed to interconnect the modules, consequently putting the entire system at high risk. Our model has the potential to shed light on many real-world phenomena, and we briefly consider its implications on recent advances in the understanding of several neurocognitive processes and diseases.

Rigidity, chaos and integration: hemispheric interaction and individual differences in metaphor comprehension.

Neurotypical individuals cope flexibly with the full range of semantic relations expressed in human language, including metaphoric relations. This impressive semantic ability may be associated with distinct and flexible patterns of hemispheric interaction, including higher right hemisphere (RH) involvement for processing novel metaphors. However, this ability may be impaired in specific clinical conditions, such as Asperger syndrome (AS) and schizophrenia. The impaired semantic processing is accompanied by different patterns of hemispheric interaction during semantic processing, showing either reduced (in Asperger syndrome) or excessive (in schizophrenia) RH involvement. This paper interprets these individual differences using the terms Rigidity, Chaos and Integration, which describe patterns of semantic memory network states that either lead to semantic well-being or are disruptive of it. We argue that these semantic network states lie on a rigidity-chaos semantic continuum. We define these terms via network science terminology and provide network, cognitive and neural evidence to support our claim. This continuum includes left hemisphere (LH) hyper-rigid semantic memory state on one end (e.g., in persons with AS), and RH chaotic and over-flexible semantic memory state on the other end (e.g., in persons with schizophrenia). In between these two extremes lie different states of semantic memory structure which are related to individual differences in semantic creativity. We suggest that efficient semantic processing is achieved by semantic integration, a balance between semantic rigidity and semantic chaos. Such integration is achieved via intra-hemispheric communication. However, impairments to this well-balanced and integrated pattern of hemispheric interaction, e.g., when one hemisphere dominates the other, may lead to either semantic rigidity or semantic chaos, moving away from semantic integration and thus impairing the processing of metaphoric language.

Investigating the structure of semantic networks in low and high creative persons.

According to Mednick's (1962) theory of individual differences in creativity, creative individuals appear to have a richer and more flexible associative network than less creative individuals. Thus, creative individuals are characterized by "flat" (broader associations) instead of "steep" (few, common associations) associational hierarchies. To study these differences, we implement a novel computational approach to the study of semantic networks, through the analysis of free associations. The core notion of our method is that concepts in the network are related to each other by their association correlations-overlap of similar associative responses ("association clouds"). We began by collecting a large sample of participants who underwent several creativity measurements and used a decision tree approach to divide the sample into low and high creative groups. Next, each group underwent a free association generation paradigm which allowed us to construct and analyze the semantic networks of both groups. Comparison of the semantic memory networks of persons with low creative ability and persons with high creative ability revealed differences between the two networks. The semantic memory network of persons with low creative ability seems to be more rigid, compared to the network of persons with high creative ability, in the sense that it is more spread out and breaks apart into more sub-parts. We discuss how our findings are in accord and extend Mednick's (1962) theory and the feasibility of using network science paradigms to investigate high level cognition.

Fine-coarse semantic processing in schizophrenia: a reversed pattern of hemispheric dominance.

Left lateralization for language processing is a feature of neurotypical brains. In individuals with schizophrenia, lack of left lateralization is associated with the language impairments manifested in this population. Beeman׳s fine-coarse semantic coding model asserts left hemisphere specialization in fine (i.e., conventionalized) semantic coding and right hemisphere specialization in coarse (i.e., non-conventionalized) semantic coding. Applying this model to schizophrenia would suggest that language impairments in this population are a result of greater reliance on coarse semantic coding. We investigated this hypothesis and examined whether a reversed pattern of hemispheric involvement in fine-coarse semantic coding along the time course of activation could be detected in individuals with schizophrenia. Seventeen individuals with schizophrenia and 30 neurotypical participants were presented with two word expressions of four types: literal, conventional metaphoric, unrelated (exemplars of fine semantic coding) and novel metaphoric (an exemplar of coarse semantic coding). Expressions were separated by either a short (250 ms) or long (750 ms) delay. Findings indicate that whereas during novel metaphor processing, controls displayed a left hemisphere advantage at 250 ms delay and right hemisphere advantage at 750 ms, individuals with schizophrenia displayed the opposite. For conventional metaphoric and unrelated expressions, controls showed left hemisphere advantage across times, while individuals with schizophrenia showed a right hemisphere advantage. Furthermore, whereas individuals with schizophrenia were less accurate than control at judging literal, conventional metaphoric and unrelated expressions they were more accurate when judging novel metaphors. Results suggest that individuals with schizophrenia display a reversed pattern of lateralization for semantic coding which causes them to rely more heavily on coarse semantic coding. Thus, for individuals with schizophrenia, speech situation are always non-conventional, compelling them to constantly seek for meanings and prejudicing them toward novel or atypical speech acts. This, in turn, may disadvantage them in conventionalized communication and result in language impairment.

Naming abilities in low-proficiency second language learners.

Difficulties in second language (L2) learning are often associated with recognizable learning difficulties in native language (L1), such as in dyslexia. However, some individuals have low L2 proficiency but intact L1 reading skills. These L2 learners experience frequent tip-of-the-tongue states while naming in L1, which indicates that they have a weakness in retrieval of phonological codes of words. The authors hypothesized that if naming ability is shared across languages, this difficulty would reemerge in L2 naming, which was tested using the tip-of-the-tongue experimental paradigm. Consistent with this hypothesis, low-proficiency L2 learners (n = 15) reported more tip-of-the-tongue states, more frequently mispronounced correctly retrieved words, and benefited less from phonological cuing compared to high-proficiency L2 learners (n = 23). It is notable that low-proficiency L2 learners performed worse than individuals with dyslexia (n = 16) on some of these measures, despite the same level of L2 proficiency. These results indicate that L2 naming difficulties of low-proficiency L2 learners are a manifestation not merely of their low L2 proficiency but rather of a general weakness in phonological word form retrieval, which is shared across languages. More broadly, the study provides further evidence for the existence of a distinct profile of cognitive weaknesses characteristic of the behavioral phenotype of low-proficiency L2 learners.

Semantic organization in children with cochlear implants: computational analysis of verbal fluency.

PURPOSE: Cochlear implants (CIs) enable children with severe and profound hearing impairments to perceive the sensation of sound sufficiently to permit oral language acquisition. So far, studies have focused mainly on technological improvements and general outcomes of implantation for speech perception and spoken language development. This study quantitatively explored the organization of the semantic networks of children with CIs in comparison to those of age-matched normal hearing (NH) peers. METHOD: Twenty seven children with CIs and twenty seven age- and IQ-matched NH children ages 7-10 were tested on a timed animal verbal fluency task (Name as many animals as you can). The responses were analyzed using correlation and network methodologies. The structure of the animal category semantic network for both groups were extracted and compared. RESULTS: Children with CIs appeared to have a less-developed semantic network structure compared to age-matched NH peers. The average shortest path length (ASPL) and the network diameter measures were larger for the NH group compared to the CIs group. This difference was consistent for the analysis of networks derived from animal names generated by each group [sample-matched correlation networks (SMCN)] and for the networks derived from the common animal names generated by both groups [word-matched correlation networks (WMCN)]. CONCLUSIONS: The main difference between the semantic networks of children with CIs and NH lies in the network structure. The semantic network of children with CIs is under-developed compared to the semantic network of the age-matched NH children. We discuss the practical and clinical implications of our findings.

Positively valenced stimuli facilitate creative novel metaphoric processes by enhancing medial prefrontal cortical activation.

A metaphor is a figure of speech in which a subject is symbolic of another unrelated object. In the present study, we examined neural patterns associated with both novel unfamiliar and conventional familiar metaphoric processing, and how these patterns are modulated by affective valence. Prior to fMRI scanning, participants received a list of word pairs (novel unfamiliar metaphors as well as conventional familiar metaphors) and were asked to denote the valence (positive, negative, or neutral) of each word pair. During scanning, participants had to decide whether the word pairs formed meaningful or meaningless expressions. Results indicate that participants were faster and more accurate at deciding that positively valenced metaphors were meaningful compared to neutral metaphors. These behavioral findings were accompanied by increased activation in the medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), and the right inferior parietal lobe (RIPL). Specifically, positively valenced novel unfamiliar metaphors elicited activation in these brain regions in addition to the left superior temporal gyrus when compared to neutral novel metaphors. We also found that the mPFC and PCC mediated the processing of positively valenced metaphors when compared to negatively valenced metaphors. Positively valenced conventional metaphors, however, elicited different neural signatures when contrasted with either neutral or negatively valenced conventional metaphors. Together, our results indicate that positively valenced stimuli facilitate creative metaphoric processes (specifically novel metaphoric processes) by mediating attention and cognitive control processes required for the access, integration, and selection of semantic associations via modulation of the mPFC. The present study is important for the development of neural accounts of emotion-cognition interactions required for creativity, language, and successful social functioning in general.

Semantic processing in native and second language: evidence from hemispheric differences in fine and coarse semantic coding.

Previous studies suggest that whereas the left hemisphere (LH) is involved in fine semantic processing, the right hemisphere (RH) is uniquely engaged in coarse semantic coding including the comprehension of distinct types of language such as figurative language, lexical ambiguity and verbal humor (e.g., Chiarello, 2003; Faust, 2012). The present study examined the patterns of hemispheric involvement in fine/coarse semantic processing in native and non-native languages using a split visual field priming paradigm. Thirty native Hebrew speaking students made lexical decision judgments of Hebrew and English target words preceded by strongly, weakly, or unrelated primes. Results indicated that whereas for Hebrew pairs, priming effect for the weakly-related word pairs was obtained only for RH presented target words, for English pairs, no priming effect for the weakly-related pairs emerged for either LH or RH presented targets, suggesting that coarse semantic coding is much weaker for a non-native than native language.