Indelible Impressions: How and Why Adolescent Experiences Expand our Brain’s Circuitry and Influence our Life Course

Indelible Impressions: How and Why Adolescent Experiences Expand our Brain’s Circuitry and Influence our Life Course

By: Amanda Gillis-Furutaka

Adolescent brains are highly impressionable. Why is this? How has this contributed to our evolutionary success? And how is this related to what teachers can do with their students outside the classroom? To answer these questions, I will first draw on research findings to explain why adolescents are strongly attracted to novelty and why the reinforcing pleasure they derive from new and exciting experiences is so powerful. Next, I’d like to share a personal story to illustrate how vivid adolescent impressions have changed my brain and the course of my life, and then reflect on the implications of adolescent impressionability for us as a species and in our adult roles as teachers, guardians, and parents.

The prefrontal cortex is the most recently evolved structure in the human brain and the last part of our brain to reach full maturity (Blakemore, 2018; Jensen, 2015). In fact, it does not become fully functional until we reach our mid-twenties. When the adolescent brain is maturing into an adult brain, it increasingly integrates and coordinates activity, enabling us to exert self-control, make balanced judgements, and remain focused far more efficiently than during our teenage years. The more primitive regions of the brain (the parts of the brain which evolved earlier than the prefrontal cortex) develop more quickly from conception. These are the regions which control our more basic fight or flight instincts and where chemicals such as dopamine and oxytocin are released. Dopamine is part of the brain’s reward system that drives learning by creating a sensation of pleasure (Sturman & Moghaddam, 2011). It is released at higher levels during adolescence than during adulthood[1]. Oxytocin is another powerful hormone that enhances feelings of well-being and, together with dopamine, leads young people to seek sensation and take risks that adults with a fully functioning prefrontal cortex would not contemplate. Knowing that the behavior of adolescents is driven by the primitive brain regions, relatively uninhibited by the prefrontal cortex, and reinforced by the release of high levels of dopamine and oxytocin, we can understand better why teenagers and young adults take risks and seek new, exciting adventures. And they undergo these novel experiences with far greater intensity than mature adults, owing to the higher level of dopamine released. The intensity of experiences enhanced by dopamine also makes them unforgettable. The fact that I can remember my first trip abroad so clearly is evidence of this, so let me tell you about what impressed me at that time.

[1] Dopamine is released in the ventral striatum, part of the more primitive brain system, which is fully functional in adolescence. The release of higher levels of dopamine during adolescence occurs because the prefrontal cortex is still under development and cannot yet fully control and inhibit the release of dopamine in this primitive part of the brain (Casey & Gavin, 2008).

My first overseas trip was an excursion for school kids to Austria in the spring of 1969, when I was 14. As a child I had been skeptical that a world beyond the English Channel really existed and was determined to believe this only when I saw it with my own eyes. But it wasn’t just my eyes that came to accept this reality. I discovered that the sounds, smells, and tastes, as well as the appearances of people, familiar objects, and even landscapes are different in another part of the world. Let me share some examples.

I’ll start with the sounds. For the first time in my life, I couldn’t understand most of the language I heard. I’d been learning French for two years and Latin for one year–compulsory subjects and of no help in Austria. I had chosen to learn German about half a year earlier. My limited knowledge was also of little help, but in a tantalizing way. I felt I was code breaking when I recognized a single word during a flow of noise that was totally intelligible to the speakers. This revelation about real spoken language (as opposed to language presented as lists of tenses, cases, and declensions in a textbook) was exciting and I wanted to crack that code.

Next, the trains, the rooms, the sheets, everywhere smelled different … and the food tasted so different! Struck by how the texture and taste of bread and cheese were so unlike what I was used to, I felt repelled at first. However, after a day or two, I started to like them even better than the familiar bread and cheese from home, because they were different. Still today, dark bread and strong cheese are among my favorite foods, probably because of the new neuronal connections I was able to make in Austria and their pleasurable association with novelty. In subsequent travels, I have also been willing to try most new local foods: piranha was delicious, and snake was OK, but I haven’t found the courage to try insects yet….

We were staying in the Austrian Alps where the emerald-green mountainsides were vertiginous and scattered with brightly colored wildflowers—so unlike the gentle rolling pastures of southern England. We hiked on the steep mountain paths and still today the feel of a mountain trail beneath my feet and warm sunshine on my face, and the scent of wildflowers exhilarate and compel me to explore more mountains as tall and beautiful as those of Austria.

So how did these vivid impressions impact my life? The neural circuitry in my brain was altered and expanded by all that was unfamiliar in this new environment because these new experiences stimulated me to build up new associations. In retrospect, I can see that I was like one of the lucky rats that the psychologist Donald Hebb took home from his lab in the 1940s (Greenfield, 2014, p. 64). They were allowed to roam freely in his house for a few weeks and later demonstrated far superior problem-solving abilities compared to their unlucky counterparts who had spent the time in a standard laboratory rat cage. This alerted scientists to the importance of freedom to explore an “enriched” environment, and subsequent formal studies have shown that new neural networks are formed by new experiences. My short sojourn in Austria provided a similarly enriched environment where I learned to anticipate, seek, and savor difference.

This explains why I was eager to take part in an exchange with a French teenager when we were sixteen. Véronique first came to stay with my family in the south of England and then I went to stay with her family in the south of France—I have always felt I got the better deal, but she may well have considered her experience more exciting than mine. Unsurprisingly, I chose to study French and German at university, and even to work overseas as an au pair in France, then travel to Canada in my gap year before starting university. After graduation, I went to Portugal to work as an English teacher and later went on to teach in China and Brazil before coming to Japan. My reasoning, both when my prefrontal cortex was still undergoing its fine tuning and later, was along these lines: Another unknown place to explore, another new language awaiting some code cracking—oooh yes! I still love the way my senses are bombarded and my mind flung open when I visit a new corner of the world, and I have encouraged my children and students to seize the opportunity to travel overseas when it arises.

Of course, each adolescent will be impressed in different ways. The classmates who joined me on the Austrian trip have not all spent a lifetime living overseas. But this impressionable stage of our development imprints on our minds the lure of new possibilities and I recommend everyone to share with young people your own teenage anecdotes about venturing out of your familiar safe zone, and to encourage them to create and share their own long-lasting impressions.

It has long been a puzzle to me that humans undergo this highly vulnerable period of development when they willingly place themselves in risky situations by exploring new places and seeking new experiences. What has been the evolutionary advantage to us as a species? My new understanding of the role that the primitive brain and neurotransmitters like dopamine and oxytocin play in adolescent behavior, has given me new insights. We are clearly not as strong or fast as many other species and we don’t see, hear, or smell as efficiently as so many others. The one thing we do excel at is adaptation to new environments. While our closest relatives, the chimps and bonobos, have remained in Africa, we have been able to spread across the whole planet because younger members of our species are unafraid to explore and learn from new environments and to move on when conditions become hostile to survival.

Young adults have been the fearless vanguards who have eagerly scouted ahead enabling our species to thrive because they were not held back by a mature prefrontal cortex.

So, how is all this relevant to the topic of this Think Tank? What do I do with my own students outside class? My third- and fourth-year seminar students and I are learning about media. I tell them about British media, and they share information about the media in their countries (mainly Japan, China, and Korea). Many seminar teachers take their students on excursions related to their specialties (exhibitions, galleries, factories, conferences, etc.) The closest I can reasonably get has been the occasional trip to the cinema when a suitable film is showing (Bohemian Rhapsody was the latest such opportunity.) But I have always had a backup activity and that is to show them Kyoto from a perspective they have never encountered before. We take to the mountain trails to enjoy the sounds, the smells, the feeling of exertion, and the thrill of looking down on Kyoto from high above. I have found out whenever I meet up with students after they have graduated, it is these hikes that they remember the most vividly and I was overjoyed a few months ago when one of these English majors told me over lunch that she has retrained as a web page designer so that she can work from home anywhere in Japan and is about to move to from Osaka to Nagano so that she can spend more time enjoying her hobby—hiking in the mountains! It seems that reaching the top of Kyoto’s Mount Hiei left an indelible impression.

I am certain that my trip to Austria as a teenager shaped the rest of my life.[2] It is also no accident that I lived in Portugal for 2 years, communist China for a year, Brazil for 5 years, and now live in Kyoto. So, let me ask you to reflect on your own formative years. Did you have some impressionable experience that shaped your own interests, beliefs, and even your life story?

[2] I also did things in my youth that I now see as bordering on reckless (taking the Trans-Siberian Express from Beijing to the USSR alone, crossing the Berlin Wall with less than an hour left on my transit visa, hitchhiking from Paraguay to Bolivia in a truck transporting contraband….).


  • Blakemore, S.-J. (2018). Inventing ourselves: The secret life of the teenage brain. Public Affairs.

  • Casey B. J., Getz, S., & Galvan, A. (2008). The adolescent brain. Developmental Review 28(1), 62-77. https://doi: 10.1016/j.dr2007.08.003

  • Jensen, F. E. (2015). The teenage brain: A neuroscientist’s survival guide to raising adolescents and young adults. Harper Collins.

  • Greenfield, S. (2014). Mind change: How digital technologies are leaving their mark on our brains. Penguin Random House UK.

  • Sturman, D. A., & Moghaddam, B. (2011). The neurobiology of adolescence: Changes in brain architecture, functional dynamics, and behavioral tendencies. Neuroscience & Biobehavioral Reviews, 35(8), 1704-171. https://doi:10.1016/j.neubiorev.2011.04.003

Amanda Gillis-Furutaka, whose prefrontal cortex has now matured, has been enjoying a settled life in Kyoto for over 30 years and seeks thrills from learning about the brain and working with the members of the JALT BRAIN SIG.

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