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Why is 18 the age of adulthood if the brain can take 30 years to mature?
Neuroscience research suggests it might be time to rethink our ideas about when exactly a child becomes an adult.
- Research suggests that most human brains take about 25 years to develop, though these rates can vary among men and women, and among individuals.
- Although the human brain matures in size during adolescence, important developments within the prefrontal cortex and other regions still take place well into one's 20s.
- The findings raise complex ethical questions about the way our criminal justice systems punishes criminals in their late teens and early 20s.
At what age does someone become an adult? Many might say that the 18th birthday marks the transition from childhood to adulthood. After all, that's the age at which people can typically join the military and become fully independent in the eyes of the law.
But in light of research showing our brains develop gradually over the course of several decades, and at different paces among individuals, should we start rethinking how we categorize children and adults?
"There isn't a childhood and then an adulthood," Peter Jones, who works as part of the epiCentre group at Cambridge University, told the BBC. "People are on a pathway, they're on a trajectory."
The prefrontal cortex, cerebellum and reward systems
One key part of that trajectory is the development of the prefrontal cortex, a significant part of the brain, in terms of social interactions, that affects how we regulate emotions, control impulsive behavior, assess risk and make long-term plans. Also important are the brain's reward systems, which are especially excitable during adolescence. But these parts of the brain don't stop growing at age 18. In fact, research shows that it can take more than 25 years for them to reach maturity.
The cerebellum also affects our cognitive maturity. But unlike the prefrontal cortex, the development of the cerebellum appears to depend largely on environment, as Dr. Jay Giedd, chair of child psychiatry at Rady Children's Hospital-San Diego, told PBS:
"Identical twins' cerebellum are no more alike than non-identical twins. So we think this part of the brain is very susceptible to the environment. And interestingly, it's a part of the brain that changes most during the teen years. This part of the brain has not finished growing well into the early 20s, even. The cerebellum used to be thought to be involved in the coordination of our muscles. So if your cerebellum is working well, you were graceful, a good dancer, a good athlete.
But we now know it's also involved in coordination of our cognitive processes, our thinking processes. Just like one can be physically clumsy, one can be kind of mentally clumsy. And this ability to smooth out all the different intellectual processes to navigate the complicated social life of the teen and to get through these things smoothly and gracefully instead of lurching. . . seems to be a function of the cerebellum."
The effects environment can bring upon the cerebellum even further complicate the question when does a child become an adult, considering the answer might depend on the kind of childhood an individual experienced.
Adulthood and the criminal justice system
These factors of cognitive develop raise many philosophical questions, but perhaps none are as important as those related to how we punish criminal, especially among young men, whose brains develop an average of two years later than women.
"The preponderance of young men engaging in these deadly, evil, and stupid acts of violence may be a result of brains that have yet to fully developed," Howard Forman, an assistant professor of psychiatry at Albert Einstein College of Medicine, told Business Insider.
So, does that mean young criminals — say, 19- to 25-year-olds — should be receive the same punishment as a 35-year-old who commits the same crime? Both criminals would still be guilty, but each might not necessarily deserve the same punishment, as Laurence Steinberg, a professor of psychology at Temple University, told Newsweek.
"It's not about guilt or innocence... The question is, 'How culpable are they, and how do we punish them?'"
After all, most countries have separate juvenile justice systems to deal with children who commit crimes. These separate systems are predicated on the idea that there ought to be a spectrum of culpability that accounts for a criminal's age. So, if we assume that the importance of age in the eyes of the justice system is based largely on cognitive differences between children and adults, then why shouldn't that culpability spectrum be modified to better match the science, which clearly shows that 18 is not the age at which the brain is fully matured?
Whatever the answer, society clearly needs some definition of adulthood in order to be able to differentiate between children and adults in order to function smoothly, as Jones suggested to the BBC.
"I guess systems like the education system, the health system and the legal system make it convenient for themselves by having definitions."
But that doesn't mean these definitions make sense outside of a legal context.
"What we're really saying is that to have a definition of when you move from childhood to adulthood looks increasingly absurd," he said. "It's a much more nuanced transition that takes place over three decades."
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A man's skeleton, found facedown with his hands bound, was unearthed near an ancient ceremonial circle during a high speed rail excavation project.
- A skeleton representing a man who was tossed face down into a ditch nearly 2,500 years ago with his hands bound in front of his hips was dug up during an excavation outside of London.
- The discovery was made during a high speed rail project that has been a bonanza for archaeology, as the area is home to more than 60 ancient sites along the planned route.
- An ornate grave of a high status individual from the Roman period and an ancient ceremonial circle were also discovered during the excavations.
Foul play?<p>A skeleton representing a man who was tossed face down into a ditch nearly 2,500 years ago with his hands bound in front of his hips was dug up during a high speed rail excavation.</p><p>The positioning of the remains have led archaeologists to suspect that the man may have been a victim of an ancient murder or execution. Though any bindings have since decomposed, his hands were positioned together and pinned under his pelvis. There was also no sign of a grave or coffin. </p><p>"He seems to have had his hands tied, and he was face-down in the bottom of the ditch," <a href="https://www.livescience.com/iron-age-murder-victim-england.html" target="_blank">said archaeologist Rachel Wood</a>, who led the excavation. "There are not many ways that you end up that way."</p><p>Currently, archaeologists are examining the skeleton to uncover more information about the circumstances of the man's death. Fragments of pottery found in the ditch may offer some clues as to exactly when the man died. </p><p>"If he was struck across the head with a heavy object, you could find a mark of that on the back of the skull," Wood said to <a href="https://www.livescience.com/iron-age-murder-victim-england.html" target="_blank">Live Science</a>. "If he was stabbed, you could find blade marks on the ribs. So we're hoping to find something like that, to tell us how he died."</p>
Other discoveries at Wellwick Farm<p>The grim discovery was made at Wellwick Farm near Wendover. That is about 15 miles north-west of the outskirts of London, where <a href="https://www.hs2.org.uk/building-hs2/hs2-green-corridor/" target="_blank">a tunnel</a> is going to be built as part of a HS2 high-speed rail project due to open between London and several northern cities sometime after 2028. The infrastructure project has been something of a bonanza for archaeology as the area is home to more than 60 ancient sites along the planned route that are now being excavated before construction begins. </p><p>The farm sits less than a mile away from the ancient highway <a href="http://web.stanford.edu/group/texttechnologies/cgi-bin/stanfordnottingham/places/?icknield" target="_blank">Icknield Way</a> that runs along the tops of the Chiltern Hills. The route (now mostly trails) has been used since prehistoric times. Evidence at Wellwick Farm indicates that from the Neolithic to the Medieval eras, humans have occupied the region for more than 4,000 years, making it a rich area for archaeological finds. </p><p>Wood and her colleagues found some evidence of an ancient village occupied from the late Bronze Age (more than 3,000 years ago) until the Roman Empire's invasion of southern England about 2,000 years ago. At the site were the remains of animal pens, pits for disposing food, and a roundhouse — a standard British dwelling during the Bronze Age constructed with a circular plan made of stone or wood topped with a conical thatched roof.</p>
Ceremonial burial site<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUzMTk0Ni9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NDgwNTIyMX0.I49n1-j8WVhKjIZS_wVWZissnk3W1583yYXB7qaGtN8/img.jpg?width=1245&coordinates=0%2C82%2C0%2C83&height=700" id="44da7" class="rm-shortcode" data-rm-shortcode-id="46cfc8ca1c64fc404b32014542221275" data-rm-shortcode-name="rebelmouse-image" alt="top down view of coffin" data-width="1245" data-height="700" />
A high status burial in a lead-lined coffin dating back to Roman times.
Photo Credit: HS2<p>While these ancient people moved away from Wellwick Farm before the Romans invaded, a large portion of the area was still used for ritual burials for high-status members of society, Wood told Live Science. The ceremonial burial site included a circular ditch (about 60 feet across) at the center, and was a bit of a distance away from the ditch where the (suspected) murder victim was uncovered. Additionally, archaeologists found an ornately detailed grave near the sacred burial site that dates back to the Roman period, hundreds of years later when the original Bronze Age burial site would have been overgrown.</p><p>The newer grave from the Roman period encapsulated an adult skeleton contained in a lead-lined coffin. It's likely that the outer coffin had been made of wood that rotted away. Since it was clearly an ornate burial, the occupant of the grave was probably a person of high status who could afford such a lavish burial. However, according to Wood, no treasures or tokens had been discovered. </p>
Sacred timber circle<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzUzMTk0Ny9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2MDAwOTQ4Mn0.eVJAUcD0uBUkVMFuMOPSgH8EssGkfLf_MjwUv0zGCI8/img.jpg?width=1245&coordinates=0%2C149%2C0%2C149&height=700" id="9de6a" class="rm-shortcode" data-rm-shortcode-id="ee66520d470b26f5c055eaef0b95ec06" data-rm-shortcode-name="rebelmouse-image" alt="An aerial view of the sacred circular monument." data-width="1245" data-height="700" />
An aerial view of the sacred circular monument.
Photo Credit: HS2<p>One of the most compelling archaeological discoveries at Wellwick Farm are the indications of a huge ceremonial circle once circumscribed by timber posts lying south of the Bronze Age burial site. Though the wooden posts have rotted away, signs of the post holes remain. It's thought to date from the Neolithic period to 5,000 years ago, according to Wood.</p><p>This circle would have had a diameter stretching 210 feet across and consisted of two rings of hundreds of posts. There would have been an entry gap to the south-west. Five posts in the very center of the circle aligned with that same gap, which, according to Wood, appeared to have been in the direction of the rising sun on the day of the midwinter solstice. </p><p>Similar Neolithic timber circles have been discovered around Great Britain, such as one near <a href="https://bigthink.com/culture-religion/stonehenge-sarsens" target="_blank">Stonehenge</a> that is considered to date back to around the same time. </p>
Being skeptical isn't just about being contrarian. It's about asking the right questions of ourselves and others to gain understanding.
- It's not always easy to tell the difference between objective truth and what we believe to be true. Separating facts from opinions, according to skeptic Michael Shermer, theoretical physicist Lawrence Krauss, and others, requires research, self-reflection, and time.
- Recognizing your own biases and those of others, avoiding echo chambers, actively seeking out opposing voices, and asking smart, testable questions are a few of the ways that skepticism can be a useful tool for learning and growth.
- As Derren Brown points out, being "skeptical of skepticism" can also lead to interesting revelations and teach us new things about ourselves and our psychology.
New study suggests the placebo effect can be as powerful as microdosing LSD.
- New research from Imperial College London investigated the psychological effects of microdosing LSD in 191 volunteers.
- While microdosers experienced beneficial mental health effects, the placebo group performed statistically similar to those who took LSD.
- Researchers believe the expectation of a trip could produce some of the same sensations as actually ingesting psychedelics.
Psychedelics: The scientific renaissance of mind-altering drugs<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="92360c805fe66c11de38a75b0967f417"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/5T0LmbWROKY?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>For the study published in eLife, the team recruited 191 citizen cosmonauts to microdose either LSD or a placebo over the course of several weeks and note the psychological effects. Volunteers were already microdosing LSD, so there was no true control. Each volunteer was given instructions on creating their own low-dose gel capsules, some containing LSD, others not. Then they mixed the capsules in envelopes so they didn't know if they were taking the real thing or not.</p><p>The trial design was ingenious: each capsule featured a QR code that was scanned after the addition of ingredients but before they were placed in the envelope so that researchers knew what they were ingesting.</p><p>The problem: volunteers sourced their own LSD. Lack of quality control could have had a profound effect on the results. </p><p>The results: LSD microdosers reported feeling more mindful, satisfied with life, and better overall; they also noticed a reduction in feelings of paranoia. </p><p>The catch: the control group felt the same thing, with no statistical difference between the groups. </p><p>Lead author Balázs Szigeti comments on the findings: "This suggests that the improvements may not be due to the pharmacological action of the drug but can instead be explained by the placebo effect." </p>
Credit: Alexander / Adobe Stock<p>Psychedelics are notoriously difficult to control for given the intensity of the experience. Yet there is precedent for the above findings. A <a href="https://link.springer.com/article/10.1007/s00213-020-05464-5" target="_blank">2019 study</a> found that 61 percent of volunteers that took a placebo instead of psilocybin felt some psychedelic effects, with a few volunteers experiencing full-on trips.</p><p style="margin-left: 20px;">"Several stated that they saw the paintings on the walls 'move' or 'reshape' themselves, others felt 'heavy. . . as if gravity [had] a stronger hold', and one had a 'come down' before another 'wave' hit her."</p><p>The Imperial team believes the expectation of a trip might have been enough to produce similar results. Senior author David Erritzoe is excited for future studies on the topic, believing they tapped into a new wave of citizen science that could push forward our knowledge of psychedelic substances.</p><p style="margin-left: 20px;">"Accounting for the placebo effect is important when assessing trends such as the use of cannabidiol oils, fad diets or supplements where social pressure or users' expectations can lead to a strong placebo response. Self-blinding citizen science initiatives could be used as an inexpensive, initial screening tool before launching expensive clinical studies."</p><p>As investments into the psychedelics market explode, with one company <a href="https://www.bloomberg.com/news/articles/2021-03-03/thiel-backed-magic-mushroom-firm-atai-hits-2-billion-valuation" target="_blank">reaching a $2 billion valuation</a>, a recurring irony appears in the long arc of psychedelics and research: the power of our minds might be enough to feel greater life satisfaction and a deeper sense of mindfulness. If that's possible with a placebo, we have to question why the rush to create more pharmacology is necessary. </p><p>This is, mind you, a separate conversation over the role of psychedelics and rituals for group bonding. The function of group cohesion around consciousness-altering substances will continue to play an important role in many communities. </p><p>Of course, we should continue to explore the efficacy of psychedelics on anxiety, depression, suicidal ideation, PTSD, and addiction. <a href="https://bigthink.com/surprising-science/antidepressant-effects" target="_self">Pharmacological dependence</a> is a stain on the psychiatry industry. Whether or not psychedelics can be prescribed for daily use remains to be seen, but we know a moneyed interest is expecting a return on investment—the above company, ATAI Life Sciences, raised $157 million in its Series D round. </p><p>When it comes to wellbeing, some things money just can't buy. How we navigate the tricky terrain of mainstreaming psychedelics remains to be seen. </p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a> and <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank" rel="noopener noreferrer">Facebook</a>. His most recent book is</em> "<em><a href="https://www.amazon.com/gp/product/B08KRVMP2M?pf_rd_r=MDJW43337675SZ0X00FH&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee" target="_blank" rel="noopener noreferrer">Hero's Dose: The Case For Psychedelics in Ritual and Therapy</a>."</em></p>