Jazz musicians reveal role of expectancy in human creativity

Temporal dynamics of uncertainty and prediction error in musical improvisation across different periods

Human improvisational acts contain an innate individuality, derived from one's experiences based on epochal and cultural backgrounds. Musical improvisation, much like spontaneous speech, reveals intricate facets of the improviser's state of mind and emotional character. However, the specific musical components that reveal such individuality remain largely unexplored. Within the framework of human statistical learning and predictive processing, this study examined the temporal dynamics of uncertainty and surprise (prediction error) in a piece of musical improvisation. This cognitive process reconciles the raw auditory cues, such as melody and rhythm, with the musical predictive models shaped by its prior experiences. This study employed the Hierarchical Bayesian Statistical Learning (HBSL) model to analyze a corpus of 456 Jazz improvisations, spanning 1905 to 2009, from 78 distinct Jazz musicians. The results indicated distinctive temporal patterns of surprise and uncertainty, especially in pitch and pitch-rhythm sequences, revealing era-specific features from the early 20th to the 21st centuries. Conversely, rhythm sequences exhibited a consistent degree of uncertainty across eras. Further, the acoustic properties remain unchanged across different periods. These findings highlight the importance of how temporal dynamics of surprise and uncertainty in improvisational music change over periods, profoundly influencing the distinctive methodologies artists adopt for improvisation in each era. Further, it is suggested that the development of improvisational music can be attributed to the adaptive statistical learning mechanisms. This study explores the period-specific characteristics in the temporal dynamics of improvisational music, emphasizing how artists adapt their methods to resonate with the cultural and emotional contexts of their times. Such shifts in improvisational ways offer a window into understanding how artists intuitively respond and adapt their craft to resonate with the cultural zeitgeist and the emotional landscapes of their respective times.

Loop and Enjoy: A Scoping Review of the Research on the Effects of Processing Fluency on Aesthetic Reactions to Auditory Stimuli

Processing fluency has been shown to affect how people aesthetically evaluate stimuli. While this effect is well documented for visual stimuli, the evidence accumulated for auditory stimuli has not yet been integrated. Our aim was to examine the relevant research on how processing fluency affects the aesthetic appreciation of auditory stimuli and to identify the extant knowledge gaps in this body of evidence. This scoping review of 19 studies reported across 13 articles found that, similarly to visual stimuli, fluency has a positive effect on liking of auditory stimuli. Additionally, we identified certain elements that impede the generalizability of the current research on the relationship between fluency and aesthetic reactions to auditory stimuli, such as a lack of consistency in the number of repeated exposures, the tendency to omit the affective component and the failure to account for personal variables such as musical abilities developed through musical training or the participants' personality or preferences. These results offer a starting point in developing novel and proper processing fluency manipulations of auditory stimuli and suggest several avenues for future research aiming to clarify the impact and importance of processing fluency and disfluency in this domain.

The association between liking, learning and creativity in music

Aesthetic preference is intricately linked to learning and creativity. Previous studies have largely examined the perception of novelty in terms of pleasantness and the generation of novelty via creativity separately. The current study examines the connection between perception and generation of novelty in music; specifically, we investigated how pleasantness judgements and brain responses to musical notes of varying probability (estimated by a computational model of auditory expectation) are linked to learning and creativity. To facilitate learning de novo, 40 non-musicians were trained on an unfamiliar artificial music grammar. After learning, participants evaluated the pleasantness of the final notes of melodies, which varied in probability, while their EEG was recorded. They also composed their own musical pieces using the learned grammar which were subsequently assessed by experts. As expected, there was an inverted U-shaped relationship between liking and probability: participants were more likely to rate the notes with intermediate probabilities as pleasant. Further, intermediate probability notes elicited larger N100 and P200 at posterior and frontal sites, respectively, associated with prediction error processing. Crucially, individuals who produced less creative compositions preferred higher probability notes, whereas individuals who composed more creative pieces preferred notes with intermediate probability. Finally, evoked brain responses to note probability were relatively independent of learning and creativity, suggesting that these higher-level processes are not mediated by brain responses related to performance monitoring. Overall, our findings shed light on the relationship between perception and generation of novelty, offering new insights into aesthetic preference and its neural correlates.

Graph Theoretical Network Structures Underlie Age-Related Differences in the Functional Connectome During Rest and Music Listening

Aging is associated with decreased functional connectivity within the default mode network, as well as auditory and reward systems which are involved in music listening. Understanding how music listening affects network organization of the aging brain, both globally and specific to the brain networks, will have implications for designing lifestyle interventions that tap into distinct networks in the brain. Here we apply graph-theory metrics of modularity, global efficiency, clustering coefficients, degrees, and betweenness centrality to compare younger and older adults (YA/OA, N=24 per group) in fMRI connectivity during rest and a music listening task. Results show a less modular but more globally efficient connectome in OAs, especially during music listening, resulting in main effects of group and task, as well as group-by-task interactions. ROI analyses indicated that the posterior cingulate is more centrally located than the medial prefrontal cortex in OAs. Overall, reduced modularity and increased global efficiency with age is in keeping with previously-observed functional reorganizations, and interaction effects show that age-related differences in baseline network organization are reflected in, potentially magnified by, music listening.

Linked auditory and motor patterns in the improvisation vocabulary of an artist-level jazz pianist

Improvising musicians possess a stored library of musical patterns forming the basis for their improvisations. According to a prominent theoretical framework by Pressing (1988), this library includes linked auditory and motor information. Though examples of libraries of melodic patterns have been shown in extant recordings by some improvising musicians, the underlying motor component has not been experimentally investigated nor related to its auditory counterparts. Here we analyzed a large corpus of ∼100,000 notes from improvisations by one artist-level jazz pianist recorded during 11 live performances with audience. We compared the library identified from these recordings to a control corpus consisting of improvisations by 24 different advanced jazz pianists. In addition to pitch, our recordings included accurate micro-timing and key velocity (i.e., force) data. Following a previously validated procedure, this information was used to identify the underlying motor patterns through correlations between relative timing and velocity between notes in different iterations of the same pitch pattern. A computational model was, furthermore, used to estimate the information content and generated entropy exhibited by recurring pitch patterns with high and low timing and velocity correlations as perceived by a stylistically enculturated expert listener. Though both corpora contained a large number of recurring patterns, the single-player corpus showed stronger evidence that pitch patterns were linked to motor programs in that within-pattern timing and velocity correlations were significantly higher compared to the control corpus. Even when controlling for potentially greater baseline levels of motor self-consistency in the single-player corpus, this effect remained significant for velocity correlations. Amongst recurring 5-tone pitch patterns, those exhibiting more consistent motor schema also used less idiomatic pitch transitions that were both more unexpected and generated more uncertain expectations in enculturated experts than less consistently repeated patterns. Interestingly, we only found partial evidence for fixed pattern boundaries as predicted by the Pressing model and therefore suggest an expanded view in which the beginning and ends of idiomatic audio-motor patterns are not always clear-cut. Our results indicate that the library of melodic patterns may be idiosyncratic to the individual improviser and relies both on motor programming and predictive processing to promote stylistic distinctiveness.

Music in the brain

Music is ubiquitous across human cultures - as a source of affective and pleasurable experience, moving us both physically and emotionally - and learning to play music shapes both brain structure and brain function. Music processing in the brain - namely, the perception of melody, harmony and rhythm - has traditionally been studied as an auditory phenomenon using passive listening paradigms. However, when listening to music, we actively generate predictions about what is likely to happen next. This enactive aspect has led to a more comprehensive understanding of music processing involving brain structures implicated in action, emotion and learning. Here we review the cognitive neuroscience literature of music perception. We show that music perception, action, emotion and learning all rest on the human brain's fundamental capacity for prediction - as formulated by the predictive coding of music model. This Review elucidates how this formulation of music perception and expertise in individuals can be extended to account for the dynamics and underlying brain mechanisms of collective music making. This in turn has important implications for human creativity as evinced by music improvisation. These recent advances shed new light on what makes music meaningful from a neuroscientific perspective.

Prediction under uncertainty: Dissociating sensory from cognitive expectations in highly uncertain musical contexts

Predictive models in the brain rely on the continuous extraction of regularities from the environment. These models are thought to be updated by novel information, as reflected in prediction error responses such as the mismatch negativity (MMN). However, although in real life individuals often face situations in which uncertainty prevails, it remains unclear whether and how predictive models emerge in high-uncertainty contexts. Recent research suggests that uncertainty affects the magnitude of MMN responses in the context of music listening. However, musical predictions are typically studied with MMN stimulation paradigms based on Western tonal music, which are characterized by relatively high predictability. Hence, we developed an MMN paradigm to investigate how the high uncertainty of atonal music modulates predictive processes as indexed by the MMN and behavior. Using MEG in a group of 20 subjects without musical training, we demonstrate that the magnetic MMN in response to pitch, intensity, timbre, and location deviants is evoked in both tonal and atonal melodies, with no significant differences between conditions. In contrast, in a separate behavioral experiment involving 39 non-musicians, participants detected pitch deviants more accurately and rated confidence higher in the tonal than in the atonal musical context. These results indicate that contextual tonal uncertainty modulates processing stages in which conscious awareness is involved, although deviants robustly elicit low-level pre-attentive responses such as the MMN. The achievement of robust MMN responses, despite high tonal uncertainty, is relevant for future studies comparing groups of listeners' MMN responses to increasingly ecological music stimuli.

Conceptual expansion via novel metaphor processing: An ERP replication and extension study examining individual differences in creativity

The aims of the present ERP study were twofold. First, to determine whether a previous study on creative cognition could be replicated, and second, to extend these findings by examining individual differences in creativity. Conceptual expansion, a capacity that is central to creativity, was induced via the processing of novel metaphors. Brain activity patterns in relation to these were compared to the processing of literal and nonsense phrases. The previous findings were replicated in that the N400, known for its sensitivity to semantic anomalies, indexed the originality of the phrases, while a post-N400 late component (LC), which is linked to semantic integration processes, indexed the appropriateness of the phrases. Moreover, only the LC was significantly sensitive to individual differences in creativity in the processing of these phrases. Differences at the level of semantic integration processes as well as the structure of knowledge organization are thereby implicated in individual differences in creativity.

Musical training mediates the relation between working memory capacity and preference for musical complexity

Previous research has examined the relationships among cognitive variables and musical training, but relatively less attention has addressed downstream effects of musical training on other psychological domains, such as aesthetic preference, and the potential impact of domain-general constructs, such as working memory. Accordingly, the present study sought to draw links between musical training, working memory capacity, and preference for musical complexity. Participants were assessed for their experience with musical training, their working-memory capacity, and their preference for musical complexity. Diverging from predictions based on vision research, our analyses revealed that musical training significantly mediated the association between working memory capacity and preference for music complexity. This significant mediation held even after a variety of sociodemographic variables (gender, education, socioeconomic status) were taken into account. Furthermore, the role of working memory capacity was domain general, such that the mediation was significant regardless of which measure of working memory capacity was used (tone, operation, or symmetry span). The current results develop a model of aesthetic preference that illuminates differences between vision and audition in terms of the multifaceted effects of complex skills training on cognition and affect. Moreover, they drive new work aimed at better understanding how domain-general constructs such as working memory capacity might interact with domain-specific cognition.

Spatiospectral brain networks reflective of improvisational experience

Musical improvisers are trained to categorize certain musical structures into functional classes, which is thought to facilitate improvisation. Using a novel auditory oddball paradigm (Goldman et al., 2020) which enables us to disassociate a deviant (i.e. musical chord inversion) from a consistent functional class, we recorded scalp EEG from a group of musicians who spanned a range of improvisational and classically trained experience. Using a spatiospectral based inter and intra network connectivity analysis, we found that improvisers showed a variety of differences in connectivity within and between large-scale cortical networks compared to classically trained musicians, as a function of deviant type. Inter-network connectivity in the alpha band, for a time window leading up to the behavioural response, was strongly linked to improvisation experience, with the default mode network acting as a hub. Spatiospectral networks post response were substantially different between improvisers and classically trained musicians, with greater inter-network connectivity (specific to the alpha and beta bands) seen in improvisers whereas those with more classical training had largely reduced inter-network activity (mostly in the gamma band). More generally, we interpret our findings in the context of network-level correlates of expectation violation as a function of subject expertise, and we discuss how these may generalize to other and more ecologically valid scenarios.

Statistical Properties of Musical Creativity: Roles of Hierarchy and Uncertainty in Statistical Learning

Creativity is part of human nature and is commonly understood as a phenomenon whereby something original and worthwhile is formed. Owing to this ability, humans can produce innovative information that often facilitates growth in our society. Creativity also contributes to esthetic and artistic productions, such as music and art. However, the mechanism by which creativity emerges in the brain remains debatable. Recently, a growing body of evidence has suggested that statistical learning contributes to creativity. Statistical learning is an innate and implicit function of the human brain and is considered essential for brain development. Through statistical learning, humans can produce and comprehend structured information, such as music. It is thought that creativity is linked to acquired knowledge, but so-called "eureka" moments often occur unexpectedly under subconscious conditions, without the intention to use the acquired knowledge. Given that a creative moment is intrinsically implicit, we postulate that some types of creativity can be linked to implicit statistical knowledge in the brain. This article reviews neural and computational studies on how creativity emerges within the framework of statistical learning in the brain (i.e., statistical creativity). Here, we propose a hierarchical model of statistical learning: statistically chunking into a unit (hereafter and shallow statistical learning) and combining several units (hereafter and deep statistical learning). We suggest that deep statistical learning contributes dominantly to statistical creativity in music. Furthermore, the temporal dynamics of perceptual uncertainty can be another potential causal factor in statistical creativity. Considering that statistical learning is fundamental to brain development, we also discuss how typical versus atypical brain development modulates hierarchical statistical learning and statistical creativity. We believe that this review will shed light on the key roles of statistical learning in musical creativity and facilitate further investigation of how creativity emerges in the brain.

Stream segregation revisited: Dynamic listening and influences of emotional context on stream perception and attention

A classical experiment of auditory stream segregation is revisited, reconceptualising perceptual ambiguity in terms of affordances and musical engagement. Specifically, three experiments are reported that investigate how listeners' perception of auditory sequences change dynamically depending on emotional context. The experiments show that listeners adapt their attention to higher or lower pitched streams (Experiments 1 and 2) and the degree of auditory stream integration or segregation (Experiment 3) in accordance with the presented emotional context. Participants with and without formal musical training show this influence, although to differing degrees (Experiment 2). Contributing evidence to the literature on interactions between emotion and cognition, these experiments demonstrate how emotion is an intrinsic part of music perception and not merely a product of the listening experience.

Statistical learning and the uncertainty of melody and bass line in music

Statistical learning is the ability to learn based on transitional probability (TP) in sequential information, which has been considered to contribute to creativity in music. The interdisciplinary theory of statistical learning examines statistical learning as a mechanism of human learning. This study investigated how TP distribution and conditional entropy in TP of the melody and bass line in music interact with each other, using the highest and lowest pitches in Beethoven’s piano sonatas and Johann Sebastian Bach’s Well-Tempered Clavier. Results for the two composers were similar. First, the results detected specific statistical characteristics that are unique to each melody and bass line as well as general statistical characteristics that are shared between the melody and bass line. Additionally, a correlation of the conditional entropies sampled from the TP distribution could be detected between the melody and bass line. This suggests that the variability of entropies interacts between the melody and bass line. In summary, this study suggested that TP distributions and the entropies of the melody and bass line interact with but are partly independent of each other.

Attention Modulates Electrophysiological Responses to Simultaneous Music and Language Syntax Processing

Music and language are hypothesized to engage the same neural resources, particularly at the level of syntax processing. Recent reports suggest that attention modulates the shared processing of music and language, but the time-course of the effects of attention on music and language syntax processing are yet unclear. In this EEG study we vary top-down attention to language and music, while manipulating the syntactic structure of simultaneously presented musical chord progressions and garden-path sentences in a modified rapid serial visual presentation paradigm. The Early Right Anterior Negativity (ERAN) was observed in response to both attended and unattended musical syntax violations. In contrast, an N400 was only observed in response to attended linguistic syntax violations, and a P3/P600 only in response to attended musical syntax violations. Results suggest that early processing of musical syntax, as indexed by the ERAN, is relatively automatic; however, top-down allocation of attention changes the processing of syntax in both music and language at later stages of cognitive processing.

Tonality Tunes the Statistical Characteristics in Music: Computational Approaches on Statistical Learning

Statistical learning is a learning mechanism based on transition probability in sequences such as music and language. Recent computational and neurophysiological studies suggest that the statistical learning contributes to production, action, and musical creativity as well as prediction and perception. The present study investigated how statistical structure interacts with tonalities in music based on various-order statistical models. To verify this in all 24 major and minor keys, the transition probabilities of the sequences containing the highest pitches in Bach's Well-Tempered Clavier, which is a collection of two series (No. 1 and No. 2) of preludes and fugues in all of the 24 major and minor keys, were calculated based on nth-order Markov models. The transition probabilities of each sequence were compared among tonalities (major and minor), two series (No. 1 and No. 2), and music types (prelude and fugue). The differences in statistical characteristics between major and minor keys were detected in lower- but not higher-order models. The results also showed that statistical knowledge in music might be modulated by tonalities and composition periods. Furthermore, the principal component analysis detected the shared components of related keys, suggesting that the tonalities modulate statistical characteristics in music. The present study may suggest that there are at least two types of statistical knowledge in music that are interdependent on and independent of tonality, respectively.

Gray Matter Correlates of Creativity in Musical Improvisation

Creativity has been defined as requiring both novelty and effectiveness, but little is known about how this standard definition applies in music. Here, we present results from a pilot study in which we combine behavioral testing in musical improvisation and structural neuroimaging to relate brain structure to performance in a creative musical improvisation task. Thirty-eight subjects completed a novel improvisation continuation task and underwent T1 MRI. Recorded performances were rated by expert jazz instructors for creativity. Voxel-based morphometric analyses on T1 data showed that creativity ratings were negatively associated with gray matter volume in the right inferior temporal gyrus and bilateral hippocampus. The duration of improvisation training, which was significantly correlated with creativity ratings, was negatively associated with gray matter volume in the rolandic operculum. Together, results show that musical improvisation ability and training are associated with gray matter volume in regions that are previously linked to learning and memory formation, perceptual categorization, and sensory integration. The present study takes a first step towards understanding the neuroanatomical basis of musical creativity by relating creative musical improvisation to individual differences in gray matter structure.

Depth and the Uncertainty of Statistical Knowledge on Musical Creativity Fluctuate Over a Composer's Lifetime

Brain models music as a hierarchy of dynamical systems that encode probability distributions and complexity (i.e., entropy and uncertainty). Through musical experience over lifetime, a human is intrinsically motivated in optimizing the internalized probabilistic model for efficient information processing and the uncertainty resolution, which has been regarded as rewords. Human's behavior, however, appears to be not necessarily directing to efficiency but sometimes act inefficiently in order to explore a maximum rewards of uncertainty resolution. Previous studies suggest that the drive for novelty seeking behavior (high uncertain phenomenon) reflects human's curiosity, and that the curiosity rewards encourage humans to create and learn new regularities. That is to say, although brain generally minimizes uncertainty of music structure, we sometimes derive pleasure from music with uncertain structure due to curiosity for novelty seeking behavior by which we anticipate the resolution of uncertainty. Few studies, however, investigated how curiosity for uncertain and novelty seeking behavior modulates musical creativity. The present study investigated how the probabilistic model and the uncertainty in music fluctuate over a composer's lifetime (all of the 32 piano sonatas by Ludwig van Beethoven). In the late periods of the composer's lifetime, the transitional probabilities (TPs) of sequential patterns that ubiquitously appear in all of his music (familiar phrase) were decreased, whereas the uncertainties of the whole structure were increased. Furthermore, these findings were prominent in higher-, rather than lower-, order models of TP distribution. This may suggest that the higher-order probabilistic model is susceptible to experience and psychological phenomena over the composer's lifetime. The present study first suggested the fluctuation of uncertainty of musical structure over a composer's lifetime. It is suggested that human's curiosity for uncertain and novelty seeking behavior may modulate optimization and creativity in human's brain.

Syntactic complexity and musical proficiency modulate neural processing of non-native music

In music, chords are organized into hierarchical structures on the basis of musical syntax and the syntax of Western music can be implicitly acquired by listeners growing up in a Western musical culture. Here, we investigated whether Western musical syntax of different complexities can be implicitly acquired by non-native listeners growing up in China. This study used electroencephalography (EEG) to measure how the neural responses to musical sequences that either follow a simple rule, i.e., finite state grammar (FSG), or a complex rule, i.e., phrase structure grammar (PSG), are affected. We tested three groups of Chinese listeners who varied in their proficiency and experience in Western music. Only the high-proficiency group had received formal Western musical training, whereas the low- and moderate-proficiency groups varied in their degree of exposure to Western music. The results showed that in the FSG condition, the event-related potentials (ERPs) evoked by regular and irregular final chords were not significantly different in the low-proficiency group. In contrast, in the moderate- and high-proficiency groups, the irregular final chords evoked an ERAN-N5 biphasic response. In the PSG condition, however, only the high-proficiency group showed an ERAN-N5 biphasic response evoked by irregular final chords. This study provides evidence that although simple structures of Western music, such as FSG, can be acquired by long-term implicit learning, the acquisition of more complex structures, such as PSG, merely from exposure to western music may not be as easy.

The neural underpinnings of cross-cultural differences in creativity

Whereas Western individualistic cultures emphasize uniqueness, collectivistic East-Asian cultures discourage it. Here we examined whether cross-cultural differences in creativity as measured by a task of divergent thinking (DT) are explained by enhanced activity in brain regions that mediate inhibitory control (e.g., the left inferior frontal gyrus [L-IFG]). We therefore predicted that the L-IFG would be "hyperactive" among individuals from East-Asian cultures compared to Western ones. In Study 1, Israeli and South Korean participants were compared on a classic DT task (AUT; "Alternate uses: Manual of instructions and interpretation"). Israelis generated more original ideas compared to South Koreans. In Study 2, Israeli participants and South Korean participants currently living in Israel were scanned while performing the AUT. In line with previous studies, the results indicate that generation of original ideas across cultures is associated with activation of the posterior cingulate cortex (PCC), which is part of the default mode network (DMN). As hypothesized, South Koreans showed enhanced activation of the L-IFG compared to Israelis. This enhanced activation was associated with lower originality scores. The cultural dimension of traditionalism, being higher in the South Korean sample than in the Israeli Sample, was related to enhance L-IFG activity, further supporting our hypothesis regarding cultural influences on inhibitory control. Furthermore, functional connectivity analysis indicated that activation of the L-IFG was positively coupled with PCC activity among Israelis and with preSMA activity among South Koreans. The results suggest that cross-cultural differences in creativity might be explained by variations in inhibitory control.

Experimental effects of acute exercise and music listening on cognitive creativity

OBJECTIVE

The purpose of this study was to extend previous experimental work suggesting that both exercise and music-based interventions may influence creativity processes, by investigating the independent influences of exercise or music stimuli on verbal creative performances in the laboratory environment.

METHODS

32 students at the University of Mississippi participated in this within-subject intervention, which included three laboratory visits per participant. Individuals participated in three 15-min, randomized experimental conditions: Treadmill walking, self-selected music, or a seated control period, and subsequently completed four creativity assessments during each visit (three tests of divergent thinking, and one test of convergent thinking), with the order of divergent thinking tasks counterbalanced. Creativity task performance was independently scored across four dependent parameters, which included fluency (i.e., total number of ideas), flexibility (i.e., total number of categories), originality (i.e., responses thought of by <5% of the sample), and elaboration (i.e., degree of supplementary detail included per idea).

RESULTS

Repeated Measures ANOVAs indicated that creativity scores for fluency (F(2, 60) = 0.63, p = 0.94), flexibility (F(2, 60) = 0.64, p = 0.53), originality (F(2, 60 = 0.23, p = 0.78), and elaboration (F(2, 60) = 2.74, p = 0.07), were not statistically significant across the visits.

CONCLUSIONS

These findings add to the equivocal body of creativity research, uniquely assessing the effects of exercise and music on verbal creativity performance. The present study further highlights the critical need for improvement in the assessment and evaluation of laboratory-assessed cognitive creativity. Methodological strategies must be examined and refined for the meaningful and credible measurement and interpretation of experimental creativity.

Rapid and flexible creativity in musical improvisation: review and a model

Creativity has been defined as the ability to produce output that is novel, useful, beneficial, and desired by an audience. But what is musical creativity, and relatedly, to what extent does creativity depend on domain-general or domain-specific neural and cognitive processes? To what extent can musical creativity be taught? To answer these questions from a reductionist scientific approach, we must attempt to isolate the creative process as it pertains to music. Recent work in the neuroscience of creativity has turned to musical improvisation as a window into real-time musical creative process in the brain. Here, I provide an overview of recent research in the neuroscience of musical improvisation, especially focusing on multimodal neuroimaging studies. This research informs a model of creativity as a combination of generative and reactive processes that coordinate their functions to give rise to perpetually novel and aesthetically rewarding improvised musical output.