The role of chunk tightness and chunk familiarity in problem solving: evidence from ERPs and fMRI

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.

Temporal expectations mediated the repetition effect in a sequence in two ways

The repetition priming effect generally refers to facilitated responding in instances where the same stimulus or a very similar stimulus repeats after an initial occurrence. Prior studies showed that the repetition priming effect was greater when repetitive stimuli appeared at expected times than when they appeared at less expected times. However, in addition to the expectation for repetition, the expectation for nonrepetitive stimuli may also arise in a sequence, especially after repetitive stimuli continuously appeared several times. This study was designed to further reveal how these two kinds of expectations influence the repetition effect in a sequence. Participants were asked to solve 3, 4 or 5 repetitive tasks followed by a novel task in the experimental group, a situation where the expectations for repetitive events arise in the first three serial positions but that for nonrepetitive events arise in the fourth, fifth and sixth serial positions, or were asked to continuously solve 3-5 repetitive tasks in the control group, a situation where only the expectation for repetitive events appears. The results showed that the repetition effect appeared steadily in the whole sequence for the control group, whereas the repetition effect appeared in the early serial positions but was reduced in the later serial position for the experimental group. The findings revealed the dual influences of temporal expectations on repetition effects in a sequence.

Uncovering neural distinctions and commodities between two creativity subsets: A meta-analysis of fMRI studies in divergent thinking and insight using activation likelihood estimation

The dual‐process theory that two different systems of thought coexist in creative thinking has attracted considerable attention. In the field of creative thinking, divergent thinking (DT) is the ability to produce multiple solutions to open‐ended problems in a short time. It is mainly considered an associative and fast process. Meanwhile, insight, the new and unexpected comprehension of close‐ended problems, is frequently marked as a deliberate and time‐consuming thinking process requiring concentrated effort. Previous research has been dedicated to revealing their separate neural mechanisms, while few studies have compared their differences and similarities at the brain level. Therefore, the current study applied Activation Likelihood Estimation to decipher common and distinctive neural pathways that potentially underlie DT and insight. We selected 27 DT studies and 30 insight studies for retrospective meta‐analyses. Initially, two single analyses with follow‐up contrast and conjunction analyses were performed. The single analyses showed that DT mainly involved the inferior parietal lobe (IPL), cuneus, and middle frontal gyrus (MFG), while the precentral gyrus, inferior frontal gyrus (IFG), parahippocampal gyrus (PG), amygdala (AMG), and superior parietal lobe were engaged in insight. Compared to insight, DT mainly led to greater activation in the IPL, the crucial part of the default mode network. However, insight caused more significant activation in regions related to executive control functions and emotional responses, such as the IFG, MFG, PG, and AMG. Notably, the conjunction analysis detected no overlapped areas between DT and insight. These neural findings implicate that various neurocognitive circuits may support DT and insight.

Cognitive control of invalid predominant ideas in insight-like problem solving

Predominant ordinary ideas are insufficient for solving insight-like problems; they interfere with subordinate original ideas and can produce a mental impasse. However, how people monitor and control invalid predominant ideas remains largely unknown. In the current study, participants were asked to solve a sequence of several similar practice problems that had the same solution to strengthen a predominant idea; the participants were then presented with an insight-like test problem that could not be solved by the predominant idea. The results showed that if the test problem was similar to the practice problems in which the predominant idea could typically be applied, it elicited greater late sustained potential (LSP) over the whole brain but no conflict-related N2 or N400 components, which suggests that the participants did not experience cognitive conflict and continued to verify the predominant but currently invalid idea. When the test problem differed from the practice problems, the items that participants reported trying to solve elicited greater N2-N400 and LSP over the whole brain, which suggests that the participants experienced cognitive conflict and exerted more reactive control over the invalid predominant idea; in contrast, the items that participants reported thinking about how to solve did not evoke greater conflict-related N2-N400 components and evoked even lower LSP, which likely indicates an ineffective state. These findings demonstrate three kinds of cognitive control toward invalid predominant ideas in situations where they are typically and not typically applied and provide empirical evidence of a mental impasse in insight-like problem-solving behaviors.

Brain Structural Correlates of Dispositional Insight and the Mediation Role of Neuroticism in Young Adults

Studies on the neural correlates of episodic insight have made significant progress in the past decades. However, the neural mechanisms underlying dispositional insight are largely unknown. In the present study, we recruited forty-four young, healthy adults and performed several analyses to reveal the neural mechanisms of dispositional insight. Firstly, a voxel-based morphometry (VBM) technique was used to explore the structural brain mechanisms of dispositional insight. We found that dispositional insight was significantly and negatively correlated with the regional gray matter volume (rGMV) in the left thalamus (TLM.L), right temporoparietal junction (TPJ.R), and left dorsal medial prefrontal cortex (DMPFC.L). Secondly, we performed a seed-based resting-state functional connectivity (RSFC) analysis to complement the findings of VBM analysis further. The brain regions of TLM.L, DMPFC.L, and TPJ.R were selected as seed regions. We found that dispositional insight was associated with altered RSFC between the DMPFC.L and bilateral TPJ, between the TPJ.R and left dorsolateral prefrontal cortex, left ventrolateral prefrontal cortex, DMPFC.L, TPJ.L, right insula, and right cerebellum. Finally, a mediation analysis found that the personality of neuroticism partially mediated the relationship between the brain region of TLM.L and dispositional insight. These findings imply that dispositional insight has a specific functional and structural neural mechanism. The personality of neuroticism may play a pivotal role in the processes of dispositional insight.

Synchronised neural signature of creative mental imagery in reality and augmented reality

Creativity, transforming imaginative thinking into reality, is a mental imagery simulation in essence. It can be incorporeal, concerns sophisticated and/or substantial thinking, and involves objects. In the present study, a mental imagery task consisting of creating a scene using familiar (FA) or abstract (AB) physical or virtual objects in real (RMI) and augmented reality (VMI) environments, and an execution task involving effectively creating a scene in augmented reality (VE), were utilised. The beta and gamma neural oscillations of healthy participants were recorded via a 32 channel wireless 10/20 international EGG system. In real and augmented environments and for both the mental imagery and execution tasks, the participants displayed a similar cortico-cortical neural signature essentially based on synchronous vs asynchronous beta and gamma oscillatory activities between anterior (i.e. frontal) and posterior (i.e. parietal, occipito-parietal and occipito-temporal) areas bilaterally. The findings revealed a transient synchronised neural architecture that appears to be consistent with the hypothesis according to which, creativity, because of its inherent complexity, cannot be confined to a single brain area but engages various interconnected networks.

Reactive control in evaluating appropriately or inappropriately novel ideas: Evidence from electrophysiological measures

Novelty and appropriateness have been considered two necessary criteria to distinguish creative ideas, but little is known about what kind of reactive control people will make when they evaluate appropriately or inappropriately novel ideas. To study this issue, high-density technology was used to record electroencephalography (EEG) signals when participants were evaluating ideas in novel & appropriate, novel & inappropriate, ordinary & appropriate, and ordinary & inappropriate conditions. An analysis of event-related potentials (ERPs) revealed that greater conflict detection-related N2 and N400-like components over the anterior scalp appeared in novel conditions than in ordinary conditions, suggesting that people are able to rapidly monitor novel ideas. Afterward, the mean amplitudes of the LPC over the left anterior scalp were greater in novel & appropriate condition than ordinary & appropriate condition, but no difference was found between novel & appropriate and novel & inappropriate conditions, which likely displayed much more reactive control was recruited to handle novel ideas and no additional control was recruited when the novel ideas were inappropriate. In addition, the mean amplitudes of the LPC/LNC over the posterior scalp were greater in novel than ordinary conditions and were also greater in inappropriate than appropriate conditions, which likely reflected the processing difficulties of conceptual understanding. These findings revealed the early rise monitoring, conceptual understanding, and reactive control mechanism underlying the evaluation of novel ideas.

Uncovering the global task-modulated brain network in chunk decomposition with Chinese characters

Chunk decomposition, which requires the mental representation transformation in accordance with behavioral goals, is of vital importance to problem solving and creative thinking. Previous studies have identified that the frontal, parietal, and occipital cortex in the cognitive control network selectively activated in response to chunk tightness, however, functional localization strategy may overlook the interaction brain regions. Based on the notion of a global brain network, we proposed that multiple specialized regions have to be interconnected to maintain goal representation during the course of chunk decomposition. Therefore, the present study applied a beta-series correlation method to investigate interregional functional connectivity in the event-related design of chunk decomposition tasks using Chinese characters, which would highlight critical nodes irrespective to chunk tightness. The results reveal a network of functional hubs with highly within or between module connections, including the orbitofrontal cortex, superior/inferior parietal lobule, hippocampus, and thalamus. We speculate that the thalamus integrates information across modular as an integrative hub while the orbitofrontal cortex tracks the mental states of chunk decomposition on a moment-to-moment basis. The superior and inferior parietal lobule collaborate to manipulate the mental representation of chunk decomposition and the hippocampus associates the relationship between elements in the question and solution phase. Furthermore, the tightness of chunks is not only associated with different processors in visual systems but also leads to increased intermodular connections in right superior frontal gyrus and left precentral gyrus. To summary up, the present study first reveals the task-modulated brain network of chunk decomposition in addition to the tightness-related nodes in the frontal and occipital cortex.

The dynamic monitoring and control mechanism in problem solving: Evidence from theta and alpha oscillations

Although both originality and value are considered necessary criteria to identify creative ideas, little is known about how original and valuable ideas are generated in the human brain. To reveal how people monitor and control ongoing processing in the pursuit of original and valuable ideas, high-density electroencephalography (EEG) was used to record electrophysiological signals when participants were performing chunk decomposition tasks via novel-appropriate, novel-inappropriate, ordinary-appropriate and ordinary-inappropriate pathways. The results showed that approximately 100 ms after the problem was presented, novel pathways showed increased theta synchronization in the frontal sites compared to ordinary pathways. Novel pathways were associated with increased alpha desynchronization over the entire brain scale. These theta and alpha oscillations likely indicated rapid monitoring and effective control of novel processing in thinking. In the latter stages of problem solving, particularly during the 2000-2600-ms intervals, increased theta synchronization with decreased alpha desynchronization was found between novel-inappropriate and novel-appropriate pathways, which likely indicated slow monitoring and less control of inappropriate processing in novel thinking. The findings demonstrated the dynamic monitoring and control mechanism in the pursuit of original and valuable ideas.

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.

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.

Brain Activations and Functional Connectivity Patterns Associated with Insight-Based and Analytical Anagram Solving

Insight is one of the most mysterious problem-solving phenomena involving the sudden emergence of a solution, often preceded by long unproductive attempts to find it. This seemingly unexplainable generation of the answer, together with the role attributed to insight in the advancement of science, technology and culture, stimulate active research interest in discovering its neuronal underpinnings. The present study employs functional Magnetic resonance imaging (fMRI) to probe and compare the brain activations occurring in the course of solving anagrams by insight or analytically, as judged by the subjects. A number of regions were activated in both strategies, including the left premotor cortex, left claustrum, and bilateral clusters in the precuneus and middle temporal gyrus. The activated areas span the majority of the clusters reported in a recent meta-analysis of insight-related fMRI studies. At the same time, the activation patterns were very similar between the insight and analytical solutions, with the only difference in the right sensorimotor region probably explainable by subject motion related to the study design. Additionally, we applied resting-state fMRI to study functional connectivity patterns correlated with the individual frequency of insight anagram solutions. Significant correlations were found for the seed-based connectivity of areas in the left premotor cortex, left claustrum, and left frontal eye field. The results stress the need for optimizing insight paradigms with respect to the accuracy and reliability of the subjective insight/analytical solution classification. Furthermore, the short-lived nature of the insight phenomenon makes it difficult to capture the associated neural events with the current experimental techniques and motivates complementing such studies by the investigation of the structural and functional brain features related to the individual differences in the frequency of insight-based decisions.

Effects of Transcranial Direct Current Stimulation on Brain Networks Related to Creative Thinking

Human creative thinking is unique and capable of generating novel and valuable ideas. Recent research has clarified the contribution of different brain networks (default mode network, DN; executive control network; salience network) to creative thinking. However, the effects of brain stimulation on brain networks during creative thinking and on creative performance have not been clarified. The present study was designed to examine the changes in functional connectivity (FC) and effective connectivity (EC) of the large-scale brain network, and the ensuing changes in creative performance, induced by transcranial direct current stimulation (tDCS). Fourteen healthy male students underwent two tDCS sessions, one with actual stimulation and one with sham stimulation, on two separate days. Participants underwent tDCS (anode over the left dorsolateral prefrontal cortex, DLPFC; cathode over the right inferior parietal lobule, IPL) for 20 min. Before and after the tDCS session, electroencephalography signals were acquired from 32 electrodes over the whole head during the creative thinking task. On FC analysis, the delta band FC between the posterior cingulate cortex and IPL significantly increased only after real stimulation. We also found that the change of flexibility score was significantly correlated with the change in: (i) delta band FC between mPFC and left lateral temporal cortex (LTC) and (ii) alpha band FC between IPL and right LTC. On EC analysis, decreased flow within the DN (from left LTC to right IPL) was observed. Our results reveal that tDCS could affect brain networks, particularly the DN, during creative thinking and modulate key FC in the generation of flexible creative ideas.

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.

An insight-related neural reward signal

Moments of insight, a phenomenon of creative cognition in which an idea suddenly emerges into awareness as an "Aha!" are often reported to be affectively positive experiences. We tested the hypothesis that problem-solving by insight is accompanied by neural reward processing. We recorded high-density EEGs while participants solved a series of anagrams. For each solution, they reported whether the answer had occurred to them as a sudden insight or whether they had derived it deliberately and incrementally (i.e., "analytically'). Afterwards, they filled out a questionnaire that measures general dispositional reward sensitivity. We computed the time-frequency representations of the EEGs for trials with insight (I) solutions and trials with analytic (A) solutions and subtracted them to obtain an I-A time-frequency representation for each electrode. Statistical Parametric Mapping (SPM) analyses tested for significant I-A and reward-sensitivity effects. SPM revealed the time, frequency, and scalp locations of several I ​> ​A effects. No A ​> ​I effect was observed. The primary neural correlate of insight was a burst of (I ​> ​A) gamma-band oscillatory activity over prefrontal cortex approximately 500 ​ms before participants pressed a button to indicate that they had solved the problem. We correlated the I-A time-frequency representation with reward sensitivity to discover insight-related effects that were modulated by reward sensitivity. This revealed a separate anterior prefrontal burst of gamma-band activity, approximately 100 ​ms after the primary I-A insight effect, which we interpreted to be an insight-related reward signal. This interpretation was supported by source reconstruction showing that this signal was generated in part by orbitofrontal cortex, a region associated with reward learning and hedonically pleasurable experiences such as food, positive social experiences, addictive drugs, and orgasm. These findings support the notion that for many people insight is rewarding. Additionally, these results may explain why many people choose to engage in insight-generating recreational and vocational activities such as solving puzzles, reading murder mysteries, creating inventions, or doing research. This insight-related reward signal may be a manifestation of an evolutionarily adaptive mechanism for the reinforcement of exploration, problem solving, and creative cognition.

Inferior frontal gyrus involvement during search and solution in verbal creative problem solving: A parametric fMRI study

In verbal creative problems like compound remote associates (CRAs), the solution is semantically distant and there is no predefined path to the solution. Therefore, people first search through the space of possible solutions before retrieving the correct semantic content by extending their search space. We assume that search and solution are both part of a semantic control process which involves the inferior frontal gyrus (IFG). Furthermore, we expect the degree of relevant semantic control areas like the IFG to depend on how much the search space needs to be extended, i.e. how semantically distant the solution is.

To demonstrate this, we created a modified CRA paradigm which systematically modulates the semantic distance from the first target word to the solution via priming. We show that brain areas (left IFG and middle temporal gyrus) associated with semantic control are already recruited during search. In addition, BOLD response in the left angular gyrus linearly correlates with search space extension. Hence, there is evidence that this process already takes place during search. Furthermore, bilateral IFG (pars orbitalis and triangularis) also correlates with search space extension but during solution. We discuss the role of the IFG in accessing semantically distant information during verbal creative problem solving.

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We present a novel way how to quantify verbal restructuring in a parametric fMRI paradigm.

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Evidence is provided that search for a solution and verbal restructuring are both part of a cognitive control process.

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Inferior frontal gyrus (IFG) and the angular gyrus are identified as part of this cognitive control process.

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BOLD activation of bilateral IFG parametrically correlates with verbal restructuring during and before solution.

Verbal insight revisited: fMRI evidence for early processing in bilateral insulae for solutions with AHA! experience shortly after trial onset

In insight problem solving solutions with AHA! experience have been assumed to be the consequence of restructuring of a problem which usually takes place shortly before the solution. However, evidence from priming studies suggests that solutions with AHA! are not spontaneously generated during the solution process but already relate to prior subliminal processing. We test this hypothesis by conducting an fMRI study using a modified compound remote associates paradigm which incorporates semantic priming. We observe stronger brain activity in bilateral anterior insulae already shortly after trial onset in problems that were later solved with than without AHA!. This early activity was independent of semantic priming but may be related to other lexical properties of attended words helping to reduce the amount of solutions to look for. In contrast, there was more brain activity in bilateral anterior insulae during solutions that were solved without than with AHA!. This timing (after trial start/during solution) x solution experience (with/without AHA!) interaction was significant. The results suggest that (a) solutions accompanied with AHA! relate to early solution‐relevant processing and (b) both solution experiences differ in timing when solution‐relevant processing takes place. In this context, we discuss the potential role of the anterior insula as part of the salience network involved in problem solving by allocating attentional resources.

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.

Resolving the Electroencephalographic Correlates of Rapid Goal-Directed Chunking in the Frontal-Parietal Network

Previous studies have revealed a specific role of the prefrontal-parietal network in rapid goal-directed chunking (RGDC), which dissociates prefrontal activity related to chunking from parietal working memory demands. However, it remains unknown how the prefrontal and parietal cortices collaborate to accomplish RGDC. To this end, a novel experimental design was used that presented Chinese characters in a chunking task, testing eighteen undergraduate students (9 females, mean age = 22.4 years) while recoding the electroencephalogram (EEG). In the experiment, radical-level chunking was accomplished in a timely stringent way (RT = 1485 ms, SD = 371 ms), whereas the stroke-level chunking was accomplished less coherently (RT = 3278 ms, SD = 1083 ms). By comparing the differences between radical-level chunking vs. stroke-level chunking, we were able to dissociate the chunking processes in the radical-level chunking condition within the analyzed time window (-200 to 1300 ms). The chunking processes resulted in an early increase of gamma band synchronization over parietal and occipital cortices, followed by enhanced power in the beta-gamma band (25-38 Hz) over frontal areas. We suggest that the posterior rhythmic activities in the gamma band may underlie the processes that are directly associated with perceptual manipulations of chunking, while the subsequent beta-gamma activation over frontal areas appears to reflect a post-evaluation process such as reinforcement of the selected rules over alternative solutions, which may be an important characteristic of goal-directed chunking.

People got lost in solving a set of similar problems

A mental set generally refers to the human brain's tendency to persist with a familiar solution and stubbornly ignore alternatives. However, if a familiar solution is unable to solve a problem similar to a previous problem, does it continue to hinder alternative solutions, and if so, how and why? To answer these questions, a Chinese character decomposition task was adopted in this study. Participants were asked to perform a practice problem that could be solved by a familiar loose chunk decomposition (LCD) solution followed by a test problem that was similar to the practice problem but could only be solved by an unfamiliar tight chunk decomposition (TCD) solution or were asked to repeatedly perform 3-5 practice problems followed by a test problem; the former is the base-set condition, and the latter is the enhanced-set condition. The results showed that the test problem recruited more activation of the inferior frontal gyrus (IFG), middle occipital cortex (MOG), superior parietal lobule (SPL) and dorsal anterior cingulate cortex (dACC) than the practice problem in the latter operation and verification stage, but almost equal activation of the dACC occurred in the early exploration stage. This likely implied that people did not think that the familiar but currently invalid LCD solution could not be used to solve the test problem; thus, it continuously competed for attention with the unfamiliar TCD solution, which required more executive control to suppress. Moreover, compared with the base-set condition, the test problem in the enhanced-set condition recruited greater activations of the IFG, SPL and dACC in the latter verification stage but less activations of regions in the left IFG and MOG in the early exploration stage. These results revealed that people less actively explored and had to work harder to operate the unfamiliar TCD solution, particularly to resolve competition from the familiar but currently invalid LCD solution. In conclusion, people lost the ability to identify errors in the familiar but currently invalid solution, which in turn decreased the exploration efforts and increased the processing demands associated with alternative solutions in the form of attentional bias and competition. This finding broadly explains the dilemma of creative problem solving.

Unconditional Perseveration of the Short-Term Mental Set in Chunk Decomposition

A mental set generally refers to the brain's tendency to stick with the most familiar solution to a problem and stubbornly ignore alternatives. This tendency is likely driven by previous knowledge (the long-term mental set) or is a temporary by-product of procedural learning (the short-term mental set). A similar problem situation is considered the factor required for perseveration of the long-term mental set, which may not be essential for the short-term mental set. To reveal the boundary conditions for perseveration of the short-term mental set, this study adopted a Chinese character decomposition task. Participants were asked to perform a practice problem that could be solved by a familiar loose chunk decomposition (loose solution) followed by a test problem, or they were asked to repeatedly perform 5-8practice problems followed by a test problem; the former is the base-set condition, and the latter is the enhanced-set condition. In Experiment 1, the test problem situation appeared to be similar to the practice problem and could be solved using the reinforced loose solution and also an unfamiliar tight chunk decomposition (tight solution) (a 2-solution problem). In Experiment 2, the test problem situation differed from the practice problem and could only be solved using an unfamiliar tight solution (a 1-solution problem). The results showed that, when comparing the enhanced-set and base-set conditions, both the accuracy rate and the response times for solving the test problem with a tight solution were worse in Experiment 1, whereas the response times were worse in Experiment 2. We concluded that perseveration of the short-term mental set was independent of the similarity between problem situations and discuss the differences in perseveration between two types of fixation.

Neural correlates of creative insight: Amplitude of low-frequency fluctuation of resting-state brain activity predicts creative insight

Creative insight has attracted much attention across cultures. Although previous studies have explored the neural correlates of creative insight by functional magnetic resonance imaging (fMRI), little is known about intrinsic resting-state brain activity associated with creative insight. In the present study, we used amplitude of low-frequency fluctuation (ALFF) as an index in resting-state fMRI (rs-fMRI) to identify brain regions involved in individual differences in creative insight, which was measured by the response time of creative Chinese character chunk decomposition. Our results showed that ALFF in the superior frontal gyrus (SFG) positively predicted creative insight, while ALFF in the middle cingulate cortex/insula cortex (MCC/IC), superior temporal gyrus/angular gyrus (STG/AG), anterior cingulate cortex/caudate nucleus (ACC/CN), and culmen/declive (CU/DC) negatively predicted creative insight. Moreover, these findings indicate that spontaneous brain activity in multiple regions related to breaking mental sets, solutions exploring, evaluation of novel solutions, forming task-related associations, and emotion experience contributes to creative insight. In conclusion, the present study provides new evidence to further understand the cognitive processing and neural correlates of creative insight.

Quantifying insightful problem solving: a modified compound remote associates paradigm using lexical priming to parametrically modulate different sources of task difficulty

Insight problem solving has been conceptualized as a dynamic search through a constrained search space, where a non-obvious solution needs to be found. Multiple sources of task difficulty have been defined that can keep the problem solver from finding the right solution such as an overly large search space or knowledge constraints requiring a change of the problem representation. Up to now, there are very few accounts that focus on different aspects of difficulty within an insight problem-solving context and how they affect task performance as well as the probability of finding a solution that is accompanied by an Aha! experience. In addition, we are not aware of any approaches investigating how knowledge constraints parametrically modulate task performance and the Aha! experience in compound remote associates (CRA) when controlling for other sources of task difficulty. Therefore, we first developed, tested, and externally validated a modified CRA paradigm in combination with lexical priming that is more likely to elicit representational change than the classical CRA tasks. Second, we parametrically estimated the effect of the knowledge constraint together with other sources of difficulty (size of the problem and search space, word length and frequency) using general linear mixed models. The knowledge constraint (and the size of the search space) was operationalized as lexical distance (measured as cosine distances) between different word pairs within this task. Our results indicate that the experimentally induced knowledge constraint still affects task performance and is negatively related to the Aha! experience when controlling for various other types of task difficulties. Finally, we will present the complete stimulus set in German language together with their statistical (i.e., item difficulty and mean solution time) and lexical properties.

Regional Homogeneity Predicts Creative Insight: A Resting-State fMRI Study

Creative insight plays an important role in our daily life. Previous studies have investigated the neural correlates of creative insight by functional magnetic resonance imaging (fMRI), however, the intrinsic resting-state brain activity associated with creative insight is still unclear. In the present study, we used regional homogeneity (ReHo) as an index in resting-state fMRI (rs-fMRI) to identify brain regions involved in individual differences in creative insight, which was compued by the response time (RT) of creative Chinese character chunk decomposition. The findings indicated that ReHo in the anterior cingulate cortex (ACC)/caudate nucleus (CN) and angular gyrus (AG)/superior temporal gyrus (STG)/inferior parietal lobe (IPL) negatively predicted creative insight. Furthermore, these findings suggested that spontaneous brain activity in multiple regions related to breaking and establishing mental sets, goal-directed solutions exploring, shifting attention, forming new associations and emotion experience contributes to creative insight. In conclusion, the present study provides new evidence to further understand the cognitive processing and neural correlates of creative insight.

The Mnemonic Effects of Novelty and Appropriateness in Creative Chunk Decomposition Tasks

Creativeness has been widely recognized as the ability to generate thoughts that are both novel (new) and appropriate (useful) (Barron, 1955). In this paper, we investigated the mnemonic effects of novelty and appropriateness in chunk decomposition tasks. Studies 1 and 2 utilized classical recognition tasks (explicit memory) and ambiguous word identification tasks (implicit memory) to reveal whether novelty and appropriateness are involved in different mnemonic systems. A 2 (familiarity) × 2 (appropriateness) experimental design was utilized in our experiments, and the four conditions were familiar-appropriate, familiar-inappropriate, novel-appropriate and novel-inappropriate. The results indicated that insight induced by novelty (novel-appropriate condition) has a better performance than other conditions; and further, found an interesting phenomenon of Zeigarnik-like effect which referred to remembering uncompleted tasks better than completed tasks (Zeigarnik, 1927). We further conducted Study 3 to ask participants to recall the encoding process (how the characters had been decomposed in the learning stage), which was more sensitive to Zeigarnik effect and indicated that performance of familiar-appropriate condition (uncompleted tasks) was better than other conditions.

Decomposing a Chunk into Its Elements and Reorganizing Them As a New Chunk: The Two Different Sub-processes Underlying Insightful Chunk Decomposition

Familiar chunks can be processed highly efficiently, and this automatic process can prohibit the problem solver from developing novel and original ways to creatively solve difficult problems. For this reason, the role of the reverse process, chunk decomposition (CD), the process by which familiar patterns are broken down into their component elements in order to be regrouped in another meaningful manner, has been generally recognized as part of the creative process. However, previous studies on this issue have mainly focused on the decomposition process of CD (the D-process), while the reorganization process of CD has been greatly neglected or has not been distinctively identified in previous work. In this paper, we argue that the R-process could be equally as important as the D-process for CD. Even if a problem solver manages to decompose a familiar chunk into its elements, he or she still may not solve the problem if these elements are not successfully organized in a new and meaningful manner. To investigate whether the cognitive mechanism of the R-process is different from that of the D-process, we designed an experiment for detecting the effects of chunk tightness, which is regarded as the key factor in CD and which can be experimentally manipulated by the radical-level (loose) and stroke-level (tight) Chinese character CD tasks in the D-process, the R-process, and the more purified organization task (the O-process task) that does not involve the decomposition process. Our results showed that the stroke-level (tight) task was more difficult than the radical-level (loose) task for the D-process. However, for the R-process, the stroke- and radical-level tasks showed no differences in performance. Moreover, for the more purified reorganization task, the O-process task, the radical-level organization and reorganization could be even more difficult than the stroke-level organization and reorganization. This result demonstrated that the cognitive processes underlying chunk decomposition and reorganization are fundamentally different. Therefore, more general concepts such as chunk restructuring that could include both D- and R-processes might be more suitable in accounting for this type of creative insight.

Role of Creativity in the Effectiveness of Cognitive Reappraisal

As a well-recognized and widely adopted emotional regulation strategy, cognitive reappraisal has generally been proven to be efficient. However, the cognitive mechanism underlying regulatory efficiency, particularly the role of creativity, in cognitive reappraisal is unclear. Although previous studies have evaluated the relationship between creativity and reappraisal from the perspectives of generation (i.e., generating cognitive reappraisals and generating creative ideas involve similar cognitive neural networks) and individual differences (i.e., the ability to generate different cognitive reappraisals can be predicted by scores on creativity-related tests), how cognitive reappraisal’s efficiency can be related to creativity is still unknown. In this research, we assessed the relationship between cognitive reappraisal’s creativity and its effectiveness in regulating negative emotion. In Study 1, participants were asked to generate reappraisals of negative stimuli and then evaluate the creativity and regulatory effectiveness of these reappraisals. The results indicated positive correlation between creativity rating and regulatory effectiveness, but we found that it was difficult for the participants to generate highly creative reappraisals on their own. Therefore, in Study 2, we showed participants well-prepared reappraisal materials that varied in their creativity and asked them to evaluate their regulatory effectiveness and creativity. The results suggested that creativity and appropriateness were significant predictors of the regulating effects of the reappraisal and that creativity was the most dominant predictor. In summary, both experiments found a positive correlation between reappraisal’s creativity and effectiveness, thus implying that creativity plays an important role in reappraisal.

Is creative insight task-specific? A coordinate-based meta-analysis of neuroimaging studies on insightful problem solving

The question of whether creative insight varies across problem types has recently come to the forefront of studies of creative cognition. In the present study, to address the nature of creative insight, the coordinate-based activation likelihood estimation (ALE) technique was utilized to individually conduct three quantitative meta-analyses of neuroimaging experiments that used the compound remote associate (CRA) task, the prototype heuristic (PH) task and the Chinese character chunk decomposition (CCD) task. These tasks were chosen because they are frequently used to uncover the neurocognitive correlates of insight. Our results demonstrated that creative insight reliably activates largely non-overlapping brain regions across task types, with the exception of some shared regions: the CRA task mainly relied on the right parahippocampal gyrus, the superior frontal gyrus and the inferior frontal gyrus; the PH task primarily depended on the right middle occipital gyrus (MOG), the bilateral superior parietal lobule/precuneus, the left inferior parietal lobule, the left lingual gyrus and the left middle frontal gyrus; and the CCD task activated a broad cerebral network consisting of most dorsolateral and medial prefrontal regions, frontoparietal regions and the right MOG. These results provide the first neural evidence of the task dependence of creative insight. The implications of these findings for resolving conflict surrounding the different theories of creative cognition and for defining insight as a set of heterogeneous processes are discussed.

The influence of element type and crossed relation on the difficulty of chunk decomposition

Chunk decomposition is an aspect of problem solving that involves decomposing a pattern into its component parts in order to regroup them into a new pattern. Previous work suggests that the primary source of difficulty in chunk decomposition is whether a problem's solution requires removing a part that is a meaningful perceptual pattern (termed a chunk) or not (a non-chunk). However, the role of spatial overlap (crossed relation or not) has been ignored in this line of research. Here, we dissociated the role of element type and crossed relation in chunk decomposition problems by employing a Chinese character transformation task. We replicated the finding that when the to-be-removed element is a non-chunk, the problem is more difficult to solve than when the element is a chunk. However, this result held only if the elements had no crossed relation. Relative to non-crossed relation, problems that involved removing elements that overlapped with the remaining character were more difficult to solve irrespective of the element type. We conclude that both element type and crossed relation can cause the difficulty of chunk decomposition and crossed relation plays more important role in preventing people from finding insightful ways to decompose chunk relative to element type.

Probing the Cognitive Mechanism of Mental Representational Change During Chunk Decomposition: A Parametric fMRI Study

Chunk decomposition plays an important role in cognitive flexibility in particular with regards to representational change, which is critical for insight problem solving and creative thinking. In this study, we investigated the cognitive mechanism of decomposing Chinese character chunks through a parametric fMRI design. Our results from this parametric manipulation revealed widely distributed activations in frontal, parietal, and occipital cortex and negative activations in parietal and visual areas in response to chunk tightness during decomposition. To mentally manipulate the element of a given old chunk, superior parietal lobe appears to support element restructuring in a goal-directed way, whereas the negatively activated inferior parietal lobe may support preventing irrelevant objects from being attended. Moreover, determining alternative ways of restructuring requires a constellation of frontal areas in the cognitive control network, such as the right lateral prefrontal cortex in inhibiting the predominant chunk representations, the presupplementary motor area in initiating a transition of mental task set, and the inferior frontal junction in establishing task sets. In conclusion, this suggests that chunk decomposition reflects mental transformation of problem representation from an inappropriate state to a new one alongside with an evaluation of novel and insightful solutions by the caudate in the dorsal striatum.