The origins of culture in the disconnected mind

Creative culture demands explanation. Take music as one example. There is no shortage of proposed evolutionary hypotheses, from functional, such as the ingroup-consolidating, outgroup-intimidating, or infant-pacifying effects of music (Mehr, Krasnow, Bryant, & Hagen, 2021; Savage et al., 2021), to explanations that treat music as an evolutionary byproduct or “auditory cheesecake” (Pinker, 2009, pp. 528–538; Pinker, 2021). The origin of music, and creative culture in general, cannot be captured by any one explanation to the exclusion of others. Something as complex as creative culture depends on myriad psychological and social processes and, as such, requires that multiple evolutionary strands be disentangled and tracked if it is to be understood at all.

The need to bridge or sidestep the integration limit is an additional hypothesis for the origin of creative culture. This hypothesis does not exclude other adaptive or byproduct-based hypotheses. What is different about the integration limit hypothesis for the origin of creative culture is that it directs us to a level of explanation that is even more distal than the usual evolutionary explanations for human uniqueness. When examining the origins of upright walking, tool use, or coalition formation, the usual explanations invoke time periods that are, at most, millions of years old and often only include hominids and other primates that are closely related to humans. If the integration limit is a property of all mammalian brains, as Horvát et al. suggest, then the use of culture to bridge or sidestep the integration limit may be a human solution to a problem that reaches tens, if not hundreds, of millions of years into the past. And if culture promotes cognitive integration, then humans may have discovered a way to either increase or maintain the size of their enlarged brains past the point of feasibility in other species. This is not to say that the integration limit is the only constraint on human brain growth (e.g., see “obstetrical dilemma”; Falk, 2016). But the cultural capacity to bridge or navigate the integration limit may be the key feature responsible for the growth of the human brain to its current size.

Adaptive cultural solutions to cognitive integration must translate to human reproductive success. If a solution does not translate to behavioral change, then the solution will be invisible to selection and, therefore, unlikely to be preserved from one generation to the next. What behavioral changes might such cultural solutions have brought about? One possibility is advancements in resource acquisition and defense. The ability to connect the fruits of cortical interconnectedness, such as long-term planning and impulse control, to reproductively relevant behaviors, such as resource acquisition and coalition defense, would have given culture its evolutionary payoff (see, e.g., Fasano et al., 2019, Kasuya-Ueba, Zhao, & Toichi, 2020, and Ye, Huang, Zhou, & Tang, 2021 for indications that music therapy may reduce aggression and foster impulse control and attention in children and adolescents). In turn, minds that were particularly drawn to cultural solutions for the integration limit would have fared better than minds that were not and would have been more likely to pass on the genetic predisposition for being drawn to such cultural solutions. Once such minds evolved, some cultural elements may have been able to unbind themselves from human reproductive interests. Over time, cultural elements that failed to promote human reproductive success (e.g., celibacy) may have nonetheless maintained their foothold in the cultural arena if their promise of cognitive integration was enough to attract human minds from generation to generation.¹

Developmental considerations

There is no need for genes to oversee all developmental contingencies when evolution occurs in relatively stable environments (in the sense that ecological features recur from generation to generation). As discussed by West-Eberhard (West-Eberhard, 2003, pp. 116–128), the same phenotypic outcome can be attributed to either genetic or environmental influences during development. Although adaptive evolution depends on change in allele frequency, genes need not be the initial instigators nor the primary bulwarks of support for adaptive change. Applied to the question of cognitive integration, some degree of genetic influence on a psychological predilection for integrative cultural elements is likely. But the functional property of these elements in promoting cognitive integration is inherited outside of the genetic pathway. Human biology need only make room for cultural elements with cognitive integration features and the rest of the functional weight can be carried by the cultural elements themselves. The only necessary conditions that the cultural elements in question must meet include (1) having the ability to integrate disconnected brain areas and (2) ensuring that the newly formed connections contribute to reproductive success. Both conditions can be met by evoked culture if individuals are predisposed to come up with the same cultural solutions anew in each generation. More often, each generation inherits a set of cultural solutions from the preceding generation—solutions that were tried and tested by dozens, if not hundreds, of ancestors over eons of time.

Transmitted cultural elements rely on three additional criteria: (1) a high, albeit less than perfect, resistance to change (i.e., cultural longevity), (2) easy transmission from person-to-person and generation-to-generation (i.e., cultural replicability), and (3) high, albeit less than perfect, transmission accuracy (i.e., cultural fidelity) (Dawkins, 1976/2006, pp. 17–18). When these conditions of transmitted culture are met, transmitted culture is rendered stable yet free to modify its peripheral features in response to changes in human ecosystems and social norms. Culture, therefore, need not sacrifice creativity and progress to its ongoing role in promoting cognitive integration. Indeed, some degree of cultural lability is necessary for further improvement to culture's role in cognitive integration.

Neurocognitive mechanisms

To say that culture creates new connections in the brain is to state the obvious. Cultural knowledge, like all experience, is associated with neuronal change. If this were not the case, there would be no basis for learning or memory. Sensory stimuli elicit nerve impulses, receptors are triggered, synapses are formed, and new cognitive circuits are created. What distinguishes the connections that are formed by cultural stimuli that promote cognitive integration from other forms of experience is the promotion of long-range circuits. Remembering what you had for breakfast is less likely to promote long-range integration than, say, a meditative or musical experience (see, e.g., Haslbeck et al., 2020, for indicative evidence of integrative effects of music therapy on preterm infants; see, also, Smith et al., 2021, for a retrospective analysis of the effect of mindfulness on functional connectivity). Although the details of how the brain uses cultural information to form previously non-existent long-range anatomical and functional connections is fodder for a research project whose scope is beyond the confines of the current essay, known facts about the brain and cognition can help us to foresee some of the project's general themes.

One theme stems from the physical organization of the neocortex. In general, neurons are packaged in circumscribed bundles, or columns, and project their connections in a three-dimensional grid-like pattern (Molnár & Rockland, 2020; Wedeen et al., 2012). Neurons within each bundle are connected to one another and, in turn, bundles send out connections to other bundles. A good metaphor that helps to visualize this pattern is that of a city (Wedeen, cited in Kurzweil, 2012, p. 82). Individual neurons can be likened to individual people forming face-to-face connections with one another (think of family members or friends conversing, sharing meals, etc.). Just as people reside in relatively cubic structures (houses, skyscrapers, etc.) that are connected via sidewalks, highways, and electric lines, neurons reside in neuronal bundles that are connected via outgoing longer-range axons to other bundles. Similarly, just as there are many paths and roadways connecting areas within a local neighborhood and relatively fewer freeways connecting whole neighborhoods, counties, and cities to one another, neurons and neuronal bundles form highly dense branching connections to neurons and neuronal bundles that are close by but have to share the same few long-range neuronal highways if they are to communicate with more distant brain areas (Markov et al., 2013).

This admittedly simplified description nevertheless taps into a fundamental truth about brain organization: it is hierarchical. Neurons do not fire in a haphazard fashion, randomly activating here, deactivating there. Instead, neurons are activated as part of neuronal networks. Some neurons are more interconnected than other neurons and so act as leaders or spokespeople for their respective neuronal networks, helping to guide and organize neuronal activation patterns spatially and temporally. Think of the neurons that form the “freeways” connecting densely-packed, outlying brain areas to one another. These highly connected neurons, or nodes, either send signals to or receive signals from a lot of other neurons. Given that they respond to or activate whole networks of neurons, they are situated at higher hierarchical levels than neurons that only interact with one or a few nearby neighbors. If new long-range connections are to be formed across vast expanses of the neocortex, cultural stimuli would be best served by connecting these already highly interconnected nodes to one another.

Cultural elements that activate high-level nodes can be more efficient at bridging the integration limit than other cultural elements. As such, we can make specific predictions about the properties shared by cultural elements that enable cognitive integration — namely, these cultural elements will be able to activate multiple components of a neuronal network with economy and efficiency. It is at this point in the discussion that a second theme emerges that will likely be at the center of future investigations of culture-mediated brain integration: symbolism. Symbolism is related to, and is ultimately founded on, the hierarchical nature of brain organization, but it is best examined at the level of cognition. High-level nodes can be said to “represent” all of the neurons within their respective neural networks (Fuster, 2005, pp. 94–98). Similarly, cultural elements acting on these nodes are expected to have symbolic properties in the sense that they represent vast stores of information that are transmitted as unitary packages.

Considering music as an example, a particular song represents all of the melodic intonations, rhythmic patterns, and emotional resonances that give it its form. By itself, a single note or beat cannot activate the high-level nodes in the brain that need to be activated for cognitive integration to take place. When nested in a rich, hierarchical structure of variegated sound in time, however, the song may very well enable cognitive integration. And if culture evolved, at least in part, to enable cognitive integration, then the cultural elements that encourage cognitive integration are likely to be fused bundles of elements that stick together and are referred to with a single symbolic gesture, utterance, picture, or piece of writing. Often, each element within such a bundle specializes in activating a specific sensory modality (e.g., sight, sound, etc.), making the bundle of which it is a part “multimodal.” When multiple sensory modalities are activated by the same cultural bundle, Hebbian principles of neuronal wiring (“fire together, wire together”) allow for large-scale integration of dispersed brain networks. Music, for example, activates more than just auditory perception—it is often tactile, visual, and kinesthetic, especially when it is performed rather than just listened to.

In addition to neuronal hierarchy and cognitive symbolism, the hedonic principle will be a theme of future research into culture's role in cognitive integration. This is because cognitive integration depends on the mind's motivation to seek it and for the seeking behavior to be reinforced with pleasure or some other positive emotional experience. If it is assumed that human brains and human culture coevolved to promote cognitive integration, then the brain is expected to engage its reward centers as a system of support for its culture-mediated connectivity-promoting capacities.

Without getting into the specifics of the neurochemistry and physiology of the brain's hedonic systems, we can expect for dopamine and its associated neuroanatomy to play a role. Dopamine, as has been discovered, is not just associated with pleasure. In addition to being itself a promoter of synaptic strengthening and connectivity (Yagishita et al., 2014), dopamine's role in the brain's hedonic system is as motivational as it is pleasureful (Salamone & Correa, 2012). Dopamine has, what is termed, “prediction error” properties (see Schultz, 2015, for review). That is, before a pleasure-inducing reward is attained, dopamine is released both in anticipation of the reward and as a motivator for reward seeking behavior. If the reward is eventually attained, dopamine levels remain high—or even increase if the reward is greater than expected. If the reward is not attained, a prediction error occurs and dopamine levels plummet. The human mind should therefore be expected to activate the dopamine system to motivate, anticipate, and be internally rewarded by the experience of cognitive integration. As such, it should be particularly attentive to cultural elements that promise cognitive integration and to experience greater degrees of positive emotion if the resulting integration is more profound than expected. Some culture-mediated experiences (e.g., mindfulness meditation) may signal high levels of cognitive integration (Rahrig et al., 2022). Furthermore, though the link may not be causal, Travis, Harung, and Lagrosen (2011) reported an association between peak experiences and cognitive integration among classically trained musicians.

Music

Music plays an important role in virtually every religious tradition. From the chants of Tibetan lamas and Gregorian monks, to the passionate singing and swaying of whirling dervishes and Hasidic Jews, religious communities throughout history relied on music to promote communal closeness and union with the divine. Song and dance are at the foundation of communal ritual in traditional societies (e.g., Pugh-Kitingan, 2014) and in many of today's temples, churches, and mosques.

Before discussing music's effects on neuroplasticity, a slight digression into anthropology and religious history is in order. The earliest examples of the existence of human (or Neanderthal) music date to between 40,000 and 60,000 years ago. Higham et al. (2012), for example, dated a flute made of a vulture's wing to a Southern German settlement that is approximately 43,000 years old. Scholars believe that the advent of music may have allowed anatomically modern humans to form coalitions that ultimately defeated their Neanderthal rivals (Conard, Malina, & Münzel, 2009), though an allegedly older Neanderthal flute casts doubt on this hypothesis (Turk, Turk, & Otte, 2020). Whenever and wherever the advent of music was, it is likely that music was the societal fulcrum around which religious and secular communal activity revolved for thousands of years.

In his foundational work on traditional shamanism, Eliade (2004/1951, pp. 168–180) dwells on the drum as a pervasive instrument and symbol of shamanic practice. Eliade points to the drum as the shaman's means of transport from ordinary reality to the supernatural realms of deceased ancestors, spirits, and deities. This function is reflected in the drum being referred to as a “horse” or “roebuck” across many North Asian and Siberian shamanic societies. Often, the drum is emblazoned with images symbolizing the three realms that it bridges during the shaman's ecstatic journey: earthly life, the underworld, and the celestial realms of spirits and deities.² And this bridging function is not incidental to the drum's musical properties. Unlike the noise-making properties of instruments that shamans sometimes employed to ward off malicious spirits, Eliade stresses that it is “musical magic” that allows the shaman to traverse across metaphysical boundaries.

Might the bridging of metaphysical boundaries be reflective of the drum's capacity to bridge previously disconnected brain networks? What distinguishes the shaman from other ancient and contemporary religious figures is the shaman's capacity for ecstasy, or what Eliade refers to as “theophany” (i.e., the infusion of the supernatural into the ordinary). We need not dwell on the supernatural elements of the shamanic experience. The shaman need not cross into an actual supernatural realm for us to note the very real propensity for musical experience (i.e., shamanic drumming or rattling) to induce a pervasive change in psychological experience. Similar uses of music and dance can be observed among the Mavlevis (i.e., “whirling dervishes”) who use music and dance to achieve communion with Allah or Christians depending on choirs (and, especially with the advent of megachurches, rock bands) to unify the congregation in Christ. The altered states that are reached may signify real changes at the level of the brain (Karmonik et al., 2016). The question is whether these changes are indicative of large-scale neurocognitive integration.

Music provides the most available example of culture applied to the task of bridging the integration limit. This is due to music's rhythmic and temporal nature. Like the patterns of brain activation, musical patterns ebb and flow in a rhythmic, wave-like flow. Notes and rhythmic beats harmonize in ways that are similar to the synchronous firing of neurons across the neocortex (Large, Herrera, & Velasco, 2015). Hierarchical structure in harmony, melody, and rhythm echoes the hierarchical structure of neuronal branching and dendritogenesis and musical hierarchy is detected by a multimodal cognitive system that detects hierarchical structure across variable spatiotemporal dimensions (Koelsch, Rohrmeier, Torrecuso, & Jentschke, 2013). There is also growing evidence that musical stimuli promote neuronal plasticity and the establishment of large-scale brain interconnectedness (Reybrouck, Vuust, & Brattico, 2018; Sharda et al., 2018; Siponkoski et al., 2020).

The mechanisms undergirding music's ability to promote cognitive integration are of some debate, but it seems that music taps into the brain's emotional core in more direct ways than are achievable by environmental sounds and even language. More specifically, music uses at least two routes to reach and activate the brain's emotional and cognitive systems. One way involves the cooptation of the brain's language centers. By imitating and exaggerating the modulation of human speech, music acts as a supernormal stimulus that can effectively exploit the brain's sensitivity to the emotional intonations of vocal communication (Juslin & Laukka, 2003). Another route by which music enables emotional and cognitive resonance is the more primordial route of entrainment (Thaut, McIntosh, & Hoemberg, 2015; Vuilleumier & Trost, 2015). Entrainment refers to the phenomenon of two or more entities reaching a synchronous state of movement. The entities can be clocks swinging their pendulums in synchrony when attached to the same piece of woodwork, participants in a communal dance grooving to the same drumbeat, or synchronously firing neurons and neuronal networks when activated by sensory signals of a musical nature. Entrainment, whether a property of biological organisms or a more pervasive artifact of the physical universe, allows for a more direct, visceral, and bodily activation of human feeling and social communion via musical stimuli.

Both supernormal activation of the brain's language systems and entrainment underlie music's capacity for cognitive integration and its power to unite individuals in communal rituals and coalitional displays. Evolutionary accounts of the origins of music often stress its latter, interindividual functions (Savage et al., 2021). But these very benefits may depend on music's activity in the brain and, specifically, on its promotion of cognitive integration at the individual level. Increasing attention is being given to the therapeutic potential of music to reestablish formerly lost brain connections, whether due to accident, dementia, mental illness, or even ordinary forgetting (Reybrouck et al., 2018). With the aid of linguistic imitation and entrainment, the musical experience activates brain networks associated with auditory perception, pattern recognition, memory, emotion, and, in particular, emotion-infused memory (e.g., nostalgia), and, in so doing, entwines severed neuronal networks and perhaps establishes connections that were never established due to the integration limit.

Although sound is music's primary medium, musical experience and expression is all-encompassing. In addition to the brain's auditory areas, music recruits networks associated with language, emotion, memory, thought, and movement (Reybrouck et al., 2018; Thaut et al., 2015). The co-activation of these networks corresponds to an enriched phenomenological experience and to the growth of lasting neuronal connections within and between them. By recruiting linguistic concepts and emotional memories, music activates the highly interconnected nodes that are at the top of the perception hierarchy. When activated, these nodes recruit all of the lower-level sensations, perceptions, and feelings that feed into them. This process likely strengthens the existing connections within each perceptual network. Entrained motor responses are often activated outside of conscious awareness, as when a person unintentionally sways, nods, taps, or even sings along to some background musical stimulus (Chauvigné, Gitau, & Brown, 2014). But the musical experience likewise activates higher-level nodes associated with executive function and movement (Bianco et al., 2021). When a highly interconnected action-oriented node is activated alongside a highly interconnected perception node, a long-range neuronal connection is formed between them and the integration limit is thereby bridged.

At the level of experience, songs can rekindle childhood memories of family vacations and first loves or reopen the closed wounds of grief and heartache. As we mature, we take on new responsibilities, develop new goals, and formulate new strategies. When a song reactivates the memory of a pervasive emotional experience from our youth, the memory can color our current goals and responsibilities with past emotional resonances. Similarly, our current goals and responsibilities can cast our old memories and experiences in a new perspective. Musical nostalgia brings us back to childhood innocence and wonder. But the nostalgia is even more poignant when experienced in the context of maturity, sophistication, and a bit of world-weariness. In entwining our past with our present, music fuses all of our time-bound personas into one, an experience that can feel transcendent. And, more likely than not, this experience is undergirded by the formation of long-range neuronal connections.

Visual art

Carl Jung, the famous psychoanalyst and protege of Freud, popularised the production of visual art as a therapeutic aid in the West. Jung was enamoured with the mandala, a geometrical pattern with a long history of religious and spiritual use in Hindu and Buddhist societies. According to Jung and his followers, the drawing of a mandala, usually circular in shape and composed in an improvisational manner, aids an individual in resolving one or another problem or overcoming some conscious or unconscious psychological impasse (Jung, Franz, von, Henderson, Jacobi, & Jaffé, 1968, pp. 230, 247–248). Seemingly disconnected from the dilemma at hand, the act of drawing a mandala presumably aids the mind in discovering heretofore hidden connections and finding pathways out of the psychological tangle that it finds itself in. Though more formal and ritualized than in Western psychotherapeutic circles, the practice of creating or meditating on a mandala has functioned as an aid to religious pedagogy and the attainment of enlightenment throughout Eastern societies for over two thousand years. In Hindu and Buddhist practice, the mandala has served to transmit theological knowledge pertaining to the identity and location of sundry supernatural entities and mystical realms. Meditating on a mandala is thought to enable seekers to discover spiritual and moral truths in ways that are more immediate than what would be possible through other instructional methods. An interesting parallel is found in Christendom's use of the labyrinth as a symbolic means by which individuals can traverse the journey from damnation to salvation and vice versa, as evidenced by the medieval and Early Modern custom of creating landscape labyrinths and labyrinthine depictions in churches and places of worship (Doob, 1992; McConnachie, 2017).

Speculative though the psychoanalytic and religious rationales for the creation or contemplation of mandalas and labyrinths may be, the human penchant for the creation of visual art requires explanation. Why do humans spend so much time and money on drawings, paintings, architectural designs, sartorial decorations, and jewelry when their limited resources can be invested in more practical endeavors? Why bother laying bricks for a future cathedral whose facade will only be appreciated by one's grandchildren? As with the emergence of music, there is no shortage of evolutionary explanations for the emergence of visual art—from practical accounts that rely on its communicative or instructional functions (e.g., cave paintings conveying useful information about hunting to our hunter-gatherer ancestors; Mithen, 1988), to the use of art and bodily ornamentation in human mate choice (Miller, 1999), to byproduct theories that view artworks as sensory exploitative artifacts (Verpooten & Nelissen, 2012). All of these and still unknown future explanations may each be true in whole or in part. I propose, in addition to these, the role of visual art in cognitive integration.³

From the view of theology or pop psychoanalysis, mentally traversing a hierarchically arranged mandala or labyrinth entails a journey toward enlightenment or Jungian individuation. At the neurocognitive level, such a journey may correlate with the formation of long-range connections in the brain. This process may be driven by visual art's capacity for symbolism. The evolution of symbolism gave our ancestors the ability to depict imagined worlds and abstract concepts. This ability was likely aided by our ancestors' newly evolved manual dexterity, originally applied to the creation and use of tools in hunting and subsistence. It is likely that manual dexterity likewise served as a stepping stone toward higher-order symbolic integration. It is much easier to draw a human body with a bird's head than it is to mentally manifest fully-formed therianthropes (i.e., mythical figures that are part-human, part-animal, considered by anthropologists to be some of the first figurative drawings by our cave-dwelling ancestors and perhaps precursors to gods and other supernatural beings; Aubert et al., 2019). Depictions of therianthropes are commonly found in Upper Paleolithic cave paintings, of which the earliest discovered example (in Sulawesi, Indonesia) is almost 44 thousand years old (Aubert et al., 2019). Therianthropes brandish human-like limbs alongside non-human characteristics such as snouts, beaks, and tails. They are often depicted in the context of hunting scenes and, according to some scholars, helped humans to catch prey via their magical affinity with the animal world. Although earlier depictions of therianthropes are lacking, it is plausible that humans were depicting imaginary entities much earlier than the archeological record suggests. After all, a therianthrope drawn in the sand with a stick is much more vulnerable to the wind and the tide than one painted in ochre on the wall of a secluded cave. According to Geary, the domain of human relationships (“folk psychology”) is cognitively separable from the domain of plants and animals (“folk biology”) (Geary, 2005, pp. 127–148). Integrating the two domains entails integrating two functionally distinct brain networks. Is it possible that a visual depiction of a part-human, part-animal being, however haphazardly drawn and to whatever humorous effect, may have inadvertently sparked the growth of a new long-range connection in the brain? More technically, could the human capacity for art have helped to bridge two disconnected brain networks by establishing a link between a symbolic representation of a human and a symbolic representation of a non-human animal in one visual scene? And have humans been using visual art for the purpose of cognitive integration ever since?

I will discuss the link between mental illness, creativity, and cognitive integration in a later section, but some mention of art therapy is warranted in connection with the utility of drawing in cognitive integration. Owing to Jung and other 20th Century psychotherapists, visual art was formally applied to the treatment of various mental illnesses, including psychosis, depression, physical and psychological trauma, and dementia. The effectiveness of visual art therapy, whether drawing, painting, or sculpting, in treating or alleviating the symptoms of mental illness is of some debate. Recent findings suggest that certain types of art therapy show promise in treating symptoms of psychological trauma, depression, and may even alleviate some of the hardships associated with dementia and physical illness (Campbell, Decker, Kruk, & Deaver, 2016; Chancellor, Duncan, & Chatterjee, 2014; Hass-Cohen & Clyde Findlay, 2019; Kongkasuwan et al., 2016; Masika, Yu, & Li, 2020; Xu et al., 2020). Art therapy's utility in treating psychosis is more equivocal (Leurent et al., 2014). Nevertheless, one of the underlying mechanisms that are thought to be responsible for art therapy's effectiveness is its ability to create or recreate new or lost connections between disconnected brain areas.

From the general view of “brain plasticity,” art therapy, including visual art therapy in the form of drawing, painting, and clay work, is thought to stimulate neurocognitive integration via multiple routes. The most straightforward route is indicated by visual art's ability to activate large, dispersed sections of the brain in ways that the more traditional verbal psychotherapy approach would not be capable of doing. In a meta-analysis testing Lusebrink's Expressive Therapies Continuum (ETC) approach to art therapy (Lusebrink, 2004), a framework marked by a distinction between different forms of art perception and expression (presumably undergirded by different functional areas of the brain), Griffith and Bingman (2020) found wide-ranging brain activation across studies, irrespective of the type of drawing task assigned to study participants. There was some support for Lasubrink's framework—i.e., art tasks that involve more thought and planning, such as the drawing of an identifiable object (e.g., a person or place) or a figure from memory (which, presumably, involves more attentional and cognitive resources), activate brain areas associated with these functions, such as the prefrontal cortex and the cingulate cortex, as well as areas in the parietal and temporal lobes. But tasks that are presumably less cognitively taxing, such as drawing abstract lines or copying, tracing, or otherwise depicting something in one's environment, likewise activate widely dispersed brain networks rather than just the localized areas devoted to visual perception, which is contrary to what the ETC framework predicts. When widely dispersed brain areas are activated simultaneously by a new task, the networks contained within these areas link up and new long-range connections are formed.

Lusebrink's ETC framework is itself predicated on the notion that visual art has the potential to integrate vast areas of the neocortex by activating different brain areas, successively or simultaneously. Although Griffith and Bingman's meta-analysis finds evidence against some aspects of the ETC framework, it does not negate it entirely. It may be, as Griffith and Bingman suggest, that different parts of the cortex are initially activated by different art tasks but that the activation is not restricted to the initially stimulated areas. Planned and thoughtful art, for example, may be initiated in the prefrontal cortex but the prefrontal cortex then activates perception and emotion areas in a top-down manner. Externally-cued or gestalt-lacking art, on the other hand, may activate lower-level perception areas first followed by higher-level cortical areas associated with abstract, symbolic thought. Either activational pattern can bring about neurocognitive integration. Other approaches to art therapy are likewise grounded, explicitly or otherwise, in neuronal plasticity principles. One approach suggests that new experiences—of any kind—generate new brain connections (Kane, 2013, cited in Griffith & Bingman, 2020). When confronted with new colors, drawing utensils, or pliable materials to be molded and shaped, new synapses are created that correspond to the cultivation of new skills and the formation of new memories.

Other approaches to art therapy that are grounded in brain plasticity principles are more specific in theory. Hass-Cohen and Clyde Findlay (2019), for example, invoke the memory reconsolidation paradigm to propose that art therapy can be used to amend traumatic memories by restructuring neurons associated with these memories. Findings in neuroscience suggest that memories are not stored as unalterable chunks of granite, never to be reshaped or reassessed once consolidated. Instead, memories are malleable and can be reformed and reassessed in light of new information (for review, see Elsey, Van Ast, & Kindt, 2018). The mechanism behind this reconsolidation process is the same that is involved in the original consolidation of a memory trace. When a person experiences something, the experience is initially stored as a temporary trace in the hippocampus. With time, this temporary trace is consolidated into a long-term memory in prefrontal and other cortical areas—especially if the experience is important or, alas, traumatic enough. But long-term memories do not always remain undisturbed. During reconsolidation, a long-term memory is brought back into the hippocampus by one or another environmental or social stimulus. Once in the hippocampus, the trace is capable of being altered. According to Hass-Cohen and Clyde Findlay, a particularly traumatic memory can be reactivated alongside neutral or positive emotions, or alongside thoughts that can recontextualize it, and subsequently reconsolidated as a long-term memory whose sharp traumatic contours are somewhat blunted. Hass-Cohen and Clyde Findlay suggest that art therapy is uniquely positioned to bring about such reconsolidation because it can reactivate sensory and emotional memories that are difficult to activate verbally. Upon being restored as a long-term memory, its neuronal signature may be quite different and, of relevance to the present discussion, marked by newly integrated circuits whose psychological effect includes healing and resilience.

The effect of visual art in promoting cognitive integration is admittedly far from settled. Even less certain is the influence of the integration limit, imposed by the evolutionary heritage of our overgrown brains, on visual art production and, less directly, on cultural trends in art and society. In the spirit of opening new avenues for research at the intersection of culture and biology, it is worth mentioning that there is ongoing research that is of relevance to the current hypothesis—i.e., that society-wide intergenerational cultural trends arise and are maintained by their contribution to ameliorating neurocognitive limitations. One study, for example, found an association between Vincent van Gogh's use of absinthe, a popular alcoholic drink among artists and intellectuals in 19th Century France, and a developing pattern in his paintings over the course of his career (Turkheimer et al., 2020). Absinthe contains thujone, a compound that, like psychosis (a psychological condition from which van Gogh suffered throughout his life), has the neurological and psychological effect of lowering sensory inhibition. At the visual level, colors, objects, and scenes blend into one another and, at the auditory level, voices and sounds can become indistinguishable. During van Gogh's periods of psychosis, which were marked by heavy absinthe use, his paintings show high levels of contrast. The researchers believe that van Gogh may have been compensating for the contrast-reducing effects of psychosis and absinthe on his visual sensorium by enhancing the level of contrast in his art. In addition, van Gogh's psychosis and absinthe use may have caused the dysregulation of the default mode network—a connected hub of brain areas that are collectively associated with the experience of a coherent “self” and its associated thoughts and emotions. When the default mode network is active alongside unrestrained sensory input, the disordered mind can fuse the inner world with the outer, leading to a tangled mess of color, emotion, and thought. Such an experience can be horrific and may have even contributed to van Gogh's suicide. But it may have likewise contributed to the rise of impressionism and its revolutionary effect on art and culture ever since.

Meditation

Cultural tools for allaying the integration limit can be grouped into two categories: bridges and workarounds. Cultural bridges bind disconnected brain networks by promoting neuronal growth. Cultural workarounds offer practical solutions to cognitive disconnection without necessarily establishing any new long-range connections in the brain. Meditation offers both sets of tools to the practitioner.

First, meditation promotes the bridging of disparate cognitive networks by deactivating the individual's sense of self. This process can be described at two levels: the subjective and the neuronal. At the level of subjective experience, the deactivation of the sense of self echoes the fundamental tenets of spiritual practices such as Buddhism, Taoism, and some mystical strains of Christianity. What all of these practices have in common is the cultivation of the loss of one's identity as a distinct entity that “owns'' its thoughts, emotions, motivations, physical sensations, and bodily properties. Although intense experiences of ego-loss may be associated with perceptible changes in one's experience of the body and mind, this loss does not entail a loss of feeling or sensation. Rather, it is a loss of the sense of a unifying entity to which all of the sensations, motivations, emotions, and thoughts are glued. In philosophical terminology, it is a loss of one's “essence,” or the ideal and central core that gives all of the other properties, or “instances,” be they thoughts, emotions, motivations, sensations, and so on, their identity as belonging to oneself. When this happens, seemingly disconnected sensations, perceptions, emotions, and thoughts can become linked because they are no longer disrupted by the imposing force of the self. The self, in other words, is no longer the mediator between thoughts, emotions, and sensations, and a more direct connection can be made between disparate psychological entities when the narrative of the self is relegated to the background.

This phenomenon can also be approached at the neuronal level. Recent studies on the psychedelic experience, brought about either by the ingestion of LSD or psilocybin mushrooms, echo religious and psychological accounts of “ego death.”⁴ Whether looking at the brain of an experienced meditator mid-contemplation or an individual who had just ingested a psychedelic substance, scientists have observed the same phenomenon: selective deactivation of the default mode network (DMN) (Brewer et al., 2011; Carhart-Harris et al., 2012, 2016; Garrison, Zeffiro, Scheinost, Constable, & Brewer, 2015). Mentioned previously in light of its contribution to the art of van Gogh and impressionism more broadly, the DMN includes a few interconnected hubs that, when co-activated, are associated with the subjective experience of the self as a distinct entity with an episodic past and an imagined future. Selflessness may not be the only dynamic of interest, however. The DMN also limits communication between brain areas by making them rely on its own pathways rather than on the formation of direct connections. Brain imaging shows that, while the DMN is downregulated during the psychedelic experience, other areas of the brain are bursting with activity (Tagliazucchi et al., 2016; note, however, that the researchers reported that parts of the DMN were also active). When disconnected brain areas are activated at the same time, they start forming direct connections with one another. In this way, both the meditative and the psychedelic experience may promote cognitive integration by, first, deactivating the part of the brain that limits communication between disparate brain areas and, second, by promoting the growth of direct connections between the disparate areas. Of relevance, a study showing increases in the size and density of dendrites among mice that were given psilocybin speaks to the cognitively integrating role of psychedelics (Shao et al., 2021).

Newly formed connections between previously disconnected cognitive and perceptual networks may underlie the unifying experience of enlightenment or transcendence so common in religious and spiritual practice. More broadly, spiritual traditions that emphasize selflessness and shamanic practices that promote the use of psychedelics may have arisen, in part, to allay the biologically-imposed costs of the integration limit. But these costs can also be allayed in other ways. Rather than forming new connections, contemplative practices such as meditation can also create workarounds for the integration limit. One such workaround can be gleaned from the now-popular practice of mindfulness meditation. Mindfulness is a Buddhist practice that exhorts practitioners to pay attention to all of the sensations, perceptions, emotions, and thoughts of the present moment without judging them. To help maintain their attention, practitioners are asked to engage in samadhi, or single-point concentration (Wallace, 2011, pp. 4, 89–111). Samadhi can be maintained by selecting one or another object of attention, be it one's breath or the sensation that occurs at the tip of one's nose. Whenever the mind starts to wander, the practitioner can gently shepherd it back to that single-pointed object of attention, which acts as a mental “haven of safety” or “secure base” (to use the terminology of attachment). Disparate thoughts and feelings need not be integrated for peace of mind to take place; they can simply be allowed to express themselves at an appropriate time and place in an orderly, linear fashion. In this way, the tumult of psychological disintegration is sidestepped.

Discussion

Although cultural phenomena attributed to the integration limit can be explained by other factors (e.g., culture as psychological pacifier or brain as pattern recognizer—Bilalić, Langner, Erb, & Grodd, 2010; McGuire & Tiger, 2009), the integration limit may complement other influences and offer some unique empirical predictions. One prediction is that larger-brained species—i.e., ones more vulnerable to the integration limit—will be more cultural than smaller-brained species. Indices of culture may include practically useful behaviors such as learned food preparation mechanisms and mating signals, but may also include imitative and artistic displays that are not otherwise explicable in biologically adaptive terms. At the intra-species level, reduced neurocognitive integration should compel individual organisms with larger brains toward more—and more varied—cultural pursuits than their smaller-brained conspecifics. Admittedly, the association between brain size and culture can be explained by other processes—e.g., cognitive adaptation to social complexity (Dunbar, 2003) and the practical and reproductive benefits of cumulative culture (Gavrilets & Vose, 2006; Muthukrishna et al., 2018). Holding factors such as social complexity, cultural utility, and mating systems constant in comparative and intra-species research can help to isolate the effects of the integration limit on cultural evolution. An additional testable prediction, previously mentioned as a potential mechanism undergirding neurocognitive integration, is that creative culture is likely to activate highly interconnected nodes within neuronal networks over nodes with predominantly local connections. It is therefore possible that, paradoxically, cultural artifacts and knowledge whose practical benefits are less than apparent might be associated with longer-range neurocognitive change than more practical artifacts and knowledge. Integration limit-associated cultural cures may bring about practical benefits indirectly, but their main antecedent is the disconnected mind. Therefore, an additional prediction, which echoes the previous discussion of mental illness and creativity, is that individuals with similarly-sized brains may nonetheless differ in their proclivity for creative culture because of differences in neurocognitive integration. Specifically, fewer long-range connections may predict greater levels of cultural interest and innovation. Advances in anatomical and functional brain imaging can corroborate or falsify these predictions.

Although the focus of the present essay is on cultural solutions to the evolution-imposed costs of our disconnected brains, other influences should not be ignored. Brain development and maintenance cannot take place without proper nutrition (Moosavi, Hosseini, Saso, & Firuzi, 2015). A healthy diet should therefore be included as a necessary, if insufficient, tool for cognitive integration. Physical and verbal intimacy, whether between caregivers and dependents or between romantic partners, is also a likely influence on healthy psychological development and cognitive integration (Lee Masson, Pillet, Boets, & Op de Beeck, 2020). Lastly, although cortico-cortical connections are the focus of the present essay, all neurogenesis depends on subcortical processes (Hamani, Stone, Garten, Lozano, & Winocur, 2011).

Nutrition and intimacy are some of the most fundamental needs in Maslow's hierarchy—needs that must be met if individuals are to develop and meet their higher-level needs for societal esteem and self-actualization. Maslow's hierarchy implies that there is no clear demarcation between biological and cultural influences on cognitive integration. Indeed, from the perspective of Bronfenbrenner's ecological systems framework, cultural and political influences can affect a person's physical and biological circumstances, either in the form of neighborhood crime levels or access to a healthy diet. But Maslow's hierarchy also implies that, as a person matures, cultural influences on cognitive development exert more influence. The needs for food, safety, and even intimacy are met by a person's immediate physical and social environment. As a person becomes more focused on acquiring societal esteem and especially self-actualization, a certain level of cultural mastery is required. Esteem in human societies is gained by the successful development of a skill. In a hunter-gatherer environment, this may have entailed the ability to cook a meal, make a spear, or conduct a religious ritual. In the modern world, it may mean the ability to read, write, or navigate the internet. After one's social and professional needs are met, more “spiritual” needs, including Maslow's concept of self-actualization, come to the fore, and intensely cultural tools and practices such as meditation and intellectual contemplation become indispensable at this stage. In short, although physical and biological factors help the individual through the initial stages of brain development, the bridge to long-range cognitive integration cannot be crossed without culture.

Cultural tools for cognitive integration arose as solutions to the evolution-imposed costs of enlarged brains. Enlarged brains are, in their turn, the product of cultural innovation. The present discussion bears on a fundamental question about human evolution: What came first, cultural development or brain growth? There are many such chicken-and-egg conundra in evolution, and a common solution is coevolution. Coevolutionary dynamics can entail either hostile interactions, as between predators and prey or parasites and hosts, or mutually-supportive interactions, as between plants and pollinating animals or between males and females in sexually reproducing species. Coevolutionary dynamics can also explain interactions between genes and culture (Whitehead, Laland, Rendell, Thorogood, & Whiten, 2019).

For the purpose of the present discussion, it makes no difference whether enlarged brains came first or whether cultural tools for cognitive integration allowed for increases in brain size. Once cultural innovation or brain enlargement occurred, increases in one led to increases in the other in a cyclical manner. Genetic mutations that promote brain growth are preserved in cultural contexts that promote cognitive integration and allay the costs of the integration limit. Such cultural contexts are ideal places for such genes to thrive. But even without any new mutations, cognitively-integrative cultures can accommodate existing genes that can promote brain growth in culturally rich environments. When mutations that promote further brain growth arrive, cultural evolution helps to assimilate them into the genome by giving them the opportunity to enlarge the cognitive capacity of an integrated brain.

Discussions of the evolution of the human brain, and human evolution more generally, can benefit from a focus on the costs of the internal environment as a selective force on anatomical, physiological, and cognitive entities. Enlarged brains and sophisticated cultures may be just as much of an evolved solution to the limitations of a disconnected brain as they are a response to climatic changes, upright walking, manual dexterity, or the cognitive demands of living in a social primate society. If this is the case, then we can expect to find other biological or cultural adaptations that evolved to address problems created by older adaptations or their byproducts. One such set of adaptations, proposed by Soper (2019), includes adaptive cognitive solutions to a previously-evolved human suicidal inclination. With the rise of culture, we should also expect sophisticated cultural innovations—innovations that would be considered adaptive if found in the biological world—that promote cognitive integration but that have no effect on reproductive success. Adaptive or otherwise, evolution is just as much a response to internal limitations as to external pressures.