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Adolescent brain development and gender: predictors of future reading habits
  1. Clare Elizabeth Caldwell
  1. School of the Arts and Media, University of New South Wales, Randwick, New South Wales, Australia
  1. Correspondence to Clare Elizabeth Caldwell, School of the Arts and Media, University of New South Wales Kensington, NSW 2052, Australia; clarecaldwell{at}yahoo.com

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In an age where the brain and mind are perpetually beguiled by the limitless visual and aural possibilities of digital media, the novel is experiencing a period of rapid transition. Typecast by a demand for long hours of steady contemplation, the existential manifestos of Proust and Conrad can feel rather old-fashioned, time-needy and, frankly, all too difficult. This occasional essay explores how an evolution in concepts around cellular neuroscience and brain connectivity have identified adolescent behaviours that could predict a shift in generational reading habits in the future.

Process and structure

A culture of reluctance among boys in their late teens to read fiction is a historical legacy of the novel itself, which since the 18th century has been strongly aligned with the feminine, the interior and the passive. Advances in neural imaging however, have enabled a deeper understanding of this disinclination. Specifically, neuroscientific evidence suggests that the pattern may not be merely related to predictable sociocultural factors and familial reading habits, but to the innate differences in cognition and language processing between genders—that is to say, the way in which boys and girls manifest the psychological inscape of a fictive experience.

In a diverse field that borrows from the realms of cognitive neuroscience, functional imaging and theory of mind, a picture of the 21st century brain and its adaptive mechanisms is emerging. The most intriguing, and perhaps most controversial of what are often studies that began at the cellular level, is a series of findings that suggests there are marked architectural and functional differences between male and female brains in the processing of text. The most rapid separation in the developmental trajectories of the brain takes place between the ages of 8 years and 22 years, when sex hormone levels are approaching their peak.1 Indeed, it appears that as the teenage brain develops, gender becomes a determining factor in how cognition evolves. In particular, the female brain develops a structure that facilitates interhemispherical communication, between left and right (figure 1B), resulting in an increased ability to function in analytical and intuitive modes. Meanwhile, the male brain develops and matures to optimise intrahemispherical functionality, with processing dominated by visual perception and coordination modes (figure 1A). This functionality develops rapidly and is well entrenched by early adulthood. As a result, teenage boys tend to gravitate towards visually and spatially oriented forms of meaning, which is evident in their significantly higher reported levels of on-screen gaming and internet usage when compared with girls.2–5 Whether this gender difference represents alteration in the wiring network of the brain, or alternatively develops as a result of structural changes in key anatomical regions such as the corpus callosum, remains unclear.6–8 If related to cortical networks, these changes may in turn have implications for neurodegenerative disease related to the concept that structures wired together, fire together and may subsequently die together.9–12

Figure 1

Connectivity detected during cognitive processing: (A) intrahemispherical activity in a male subject shown in blue; (B) interhemispherical activity in a female subject shown in orange. (Adapted from Ingalhalikar et al [1]). (C) Action and adventure— learnt gender behaviour or neurobiological difference?

Part of this phenomenon has been attributed to the brain connections that are made when semantic language systems establish themselves in early life. It is certainly evident that concepts such as memory, perception and imagination rely on the associations between linguistic expression, physical experience and social context to make a situation seem real. In these instances, the compulsion of the brain is to superimpose what it knows over what it does not know in a search for meaning. This process is often referred to as simulation. When an individual reads a novel, it is precisely this method—this mechanism by which fiction elicits notions of character, scene, allegory and paradox—that allows them to comprehend subjects beyond the realms of their own personal experience.

Fiction as mimic

Theory of mind speaks of the ability to immerse oneself in this fictional world by removing notions of philosophical determinism and filling the blank spaces with imagination. It is in this field that research by cognitive linguists and neuroscientists has made a number of significant advances over the past 15 years. Critically, fMRI and PET appear increasingly able to track the brain’s reaction to reading simple, evocative words.13 When a subject silently reads an active word such as ‘kick’, the motor cortex lights up, with category-specific differential activation so precise that the illumination delineates whether the activity is arm-related, face-related or leg-related.14 In addition, humans have been found to use the same cerebral networks to understand the physical characteristics of fictional characters as they do to interpret those of real people.15 16

Studies reveal that reading expressive textual metaphors such as ‘leathery hands’ stimulates a response from the somatosensory cortex, which is generally only activated when a person physically feels such a texture.17 Similarly, abstract linguistic signifiers such as ‘garlic’ or ‘cinnamon’ evoke identical responses from the primary olfactory cortex to those experienced when a subject actually smells the aroma.18 Behavioural neuroscience has confirmed that active phraseology arouses the human brain in a fashion identical to physical action. These findings support a growing consensus among the schools of brain science, cognitive linguistics and philosophy that the cortical cell assemblies employed to process and implement physical actions in humans do not act in a master and slave interplay. Instead, it is now understood that cognition and social acuity are progressively built from the repetitive interaction of the motor, sensory and language centres of the brain.19

Each of these findings reinforces the Hebbian articulation of synaptic neuroplasticity as essential to the process of learning, yet reveals little about why boys in particular have a propensity to drift away from reading literature at the onset of puberty. Given that the most popular genres among teenage boys relate to war, crime and science fiction—in that order—there is much to suggest that the spatial and visual partiality that has been detected by fMRI studies at the critical stages of puberty reflects a proclivity towards the physical.20 However, it remains to be determined whether that desire to seek out stories of action and adventure among adolescent boys, and the men that they will become, is derived from childhood exposure to learnt gender behaviours or to genuine neurobiological differences (figure 1C). In support of the former, numerous studies have suggested that children gain a conceptual grasp of metacognitive terminology—I think, I wonder, I guess—not through explicit exposure to ideas, but from the cognitive dexterity gained by inferring the beliefs and emotions of others through fictional scenarios.21–24

Put simply, knowing how to understand another’s mind is learnt, not taught, through the integration of perception and experience. In addition, avid fiction readers appear to possess a heightened ability to experience the emotions of others, often associated with above-average skills in peer collaboration and social relations, further cementing the notion that the imagined has the capacity to transfer into the lived experience. Indeed, when Freud wrote his 24 volume magnum opus on human psychology more than a century ago, the books dedicated to the interpretation of dreams—those nightly excursions into the fictions of our mind—pinpointed the unconscious as the richest source of imaginary material.25 Freud claimed that dreams were the product of subliminal wish fulfilment and part of a wider structure that mirrored the mental activities of waking life. His suppositions, which will remain eternally contentious, do seem to contribute an explanation to fiction’s almost universal allure. Fiction does not simply seduce the reader with its content, but rather it creates a relationship with the past and with other worlds that percolates through the pages and into life.

New technology and the evolving brain

Whether fiction is able to stimulate theory of mind better than other forms of learning will continue to be debated. The genre’s inherent fictionality—its figurative language and cognitive reliance on semiotics—provides rich fodder for the mind, yet there is something that refuses to engage fully with the ‘empathy-altruism’ hypothesis often employed to explain the fundamental benefits of the form.26 For young boys and their relationship with the fiction novel, this is particularly problematic, with heuristic models of neurobiology confirming that when adolescent boys seek out pleasure, they are less likely to be propelled by goal-driven reward than they are by stimulus-driven motivation. This bias is credited with producing the impulsive, novelty-seeking and risk-taking behaviours typical to adolescent boys that tend to cancel out the quiet introspection of reading.27 This is nowhere more apparent than in the rapid and enthusiastic adoption of new media by boys over the past two decades.

History has already shown that the developing brain is particularly amenable to the instant reward of the screen, with longitudinal research determining that children who watched a moderate level of television from infancy onwards demonstrated higher levels of inattention, impulsivity and distractibility in later childhood.28 However, of most interest was the finding that the elements of visual and aural immersion that typify these interactions necessitate the activation of the sensorimotor cortex, while simultaneously inhibiting the prefrontal cortices—those areas responsible for the heavy computational burden of logic and self-awareness.29 30

The temptation, of course, among the many studies that have linked neuroscience with behavioural models, is to lean on the findings to develop reductive sociological theories. However, as we move towards an era in which the ‘death of the novel’ has been predicted, a more productive approach may be to use the research as a way of tracing tendencies. In this way, it may be possible to determine whether the slow diminution of fiction reading in teenage boys is merely a sociological phenomenon or the result of the intriguing process of pruning and adaption in the human brain.

References

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Footnotes

  • Contributors CEC conceived and wrote the manuscript and is the sole author. Helen Groth provided critical comment on the submission.

  • Funding CEC was supported by an Australian Postgraduate Award (UNSW).

  • Competing interests CC and the adolescent in Figure 1 are related to the Editor in Chief.

  • Patient consent Consent was provided by the Guardian (author CC) and the adolescent in figure 1.

  • Provenance and peer review Commissioned; internally peer reviewed.

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