Brain Development, Longevity and the Cost of Outdated Age Categories.
How outdated age categories affect young people, older adults and public policy
This article did not begin with questions about brain development, ageing or public policy.
It began with something much simpler.
I found myself increasingly frustrated by the number of doctors promoting completely different dietary approaches with equal authority. One promotes a carnivore diet and warns against eating vegetables, literally. Another promotes veganism and advises against meat. Others again promote supplements, peptides, anti-ageing products or specialised health programs.
For consumers, the result is confusion in areas vital to their long-term health. Every approach appears to have experts, peer-reviewed studies, and proof behind it. How is the consumer supposed to navigate a marketplace where experts disagree on the very basics of what constitutes a well-balanced diet?
The more I looked into it, the more I wondered how medicine became a marketplace where professionals compete for attention, influence, and customers. Didn’t doctors swear an oath to do good, rather than to chase clout and market share?
From the 1990s onwards, Australia progressively deregulated professional health advertising. As a result, doctors and clinics became increasingly able to market their services directly to consumers. Medicine moved firmly into the marketplace, and the consequences are now visible across the entire human lifespan.
Young adults have become a primary target for major cosmetic procedures, including breast augmentation and rhinoplasty. The market continues to grow. Driven by social media pressure, young people are bombarded with unrealistic beauty ideals while clinics directly advertise solutions to their manufactured insecurities.
At the other end of life, the anti-ageing and longevity market is exploding. Supplements, peptides, and longevity clinics promise to optimise the aging body and extend the prime of life.
The paradox is stark: on the one hand, young adults are encouraged to believe they do not yet look good enough; on the other, older adults are driven to want to remain young forever.
This article is not simply about cosmetic surgery, longevity clinics or diet gurus. It is about a much larger issue.
Scientific knowledge has expanded. Human lifespans have extended. The realities of work, education, and family life have changed fundamentally. Yet, age categories embedded throughout our government, legal systems, and public institutions remain frozen in time.
The question is simple: Should numbers created in a different era still serve as the benchmarks for major decisions that dictate our modern lives?
The Commercialisation of Human Vulnerability
Doctors, Social Media and the Business of Health
Medicine now operates in a very different environment from the one that existed for most of the twentieth century. Doctors compete for attention. Clinics market directly to consumers. Social media rewards simple messages, strong opinions and certainty.
This commercial environment creates opportunities, but it also creates risks. A young person scrolling through social media may encounter cosmetic-surgery advertising, appearance-focused influencers and highly edited images. An older person may see advertisements promising biological-age reversal, longevity gains or extended vitality.
In both cases, ordinary human concerns become commercial opportunities. The issue is not every product, procedure or practitioner. The issue is the growing ability of modern markets to identify insecurities and then sell solutions.
It would be too simplistic to argue that competition has been entirely harmful. Increased choice, innovation, consumer information and access to services have delivered real benefits. Advocates of competition reforms argued that healthcare should not be immune from the pressures that improve quality, efficiency and responsiveness in other sectors of the economy.
The more interesting question is whether healthcare differs from most other markets because consumers are often making decisions when they are anxious, vulnerable or uncertain. Consequently, the challenge is not whether markets belong in healthcare. It is where the line should be drawn between professional advice and commercial persuasion.
What happens when doctors are both trusted advisers and commercial competitors? These commercial pressures are not occurring in small niche markets.
Globally, almost 38 million aesthetic procedures were performed in 2024. This includes surgical and non-surgical procedures. The total increased by more than 40 per cent compared with 2020. According to the International Society of Aesthetic Plastic Surgery’s 2024 global survey, people aged 18 to 34 accounted for 54 per cent of breast augmentation procedures and 60.1 per cent of rhinoplasties.
Australia also has a substantial cosmetic-procedures market. However, its size is difficult to measure because figures do not always separate surgical operations from non-surgical procedures and related services.
At the other end of life, anti-ageing surgery and longevity products have become a large and expanding market. Older generations are systematically are in the line of marketing campaigns that weaponise the fear of economic irrelevance and workplace ageism, convincing them that surgeries like facelifts and eyelid operations are essential tools to stay competitive. Under the guise of “looking refreshed,” medicine has turned the natural process of aging into a corporate defect that requires surgical correction
Are these industries simply responding to human anxieties, or are helping to create them? What happens when some of the fastest-growing health markets focus on age-related insecurities at both ends of the lifespan?
Why Age Categories Matter – The Framework Behind Modern Life
A young person may be expected to vote, work, drive, enter into contracts, join the military and more. These responsibilities do not all begin at the same age. A young person may be treated as capable of taking on serious responsibilities in one area, while still being viewed as vulnerable and in need of protection in another.
Most people assume age categories are based primarily on science. In reality, many emerged gradually from legal, administrative, demographic and economic needs. They helped governments organise schools, employment, pensions, voting systems and public services.
They were designed to simplify a complex world,allocate resources and attribute guilt. The question is whether frameworks developed for a different social and demographic environment should be reviewed to meet the demands of a changed world.
How often do we stop to ask where these numbers came from and whether they still make sense? Age-based systems are useful. Today we live longer than previous generations and know much more about human development than we did when many of these categories were established.
At the same time, many of the social milestones that once marked adulthood, such as leaving home, establishing a career and forming a family, now occur later for many people.
The categories have largely stayed the same. The lives they are intended to describe have not.
If these categories were being designed today, would we choose the same numbers?
The Evidence-to-Policy Gap – What Makes Governments Move Quickly
The argument in this article is not that governments are incapable of responding to evidence. History shows the opposite.
For example:
- Australia introduced compulsory seat-belt laws after growing evidence that they significantly reduced serious injury and death in motor vehicle accidents.
- Bicycle-helmet legislation followed as evidence accumulated about head injuries and the long-term consequences of brain trauma.
- Tobacco control provides another example. Evidence linking smoking with disease eventually translated into increasingly restrictive advertising rules, graphic health warnings and plain packaging.
- Governments around the world demonstrated during the COVID-19 pandemic that public policy can change within weeks or months when issues are treated as urgent.
I am not judging the necessity of these policy changes, some actions remain deeply controversial, however, they illustrate that when governments decide that evidence justifies intervention, they are capable of reviewing long-standing assumptions, changing legislation and introducing new regulatory frameworks quickly.
Why have age categories largely escaped the same level of scrutiny?
For more than three decades, research has been challenging assumptions about development, vulnerability and ageing. Yet many of the key thresholds that organise modern life remain largely unchanged.
Brain development provides one of the clearest examples of this gap.
Brain Development and the 18-Year Threshold – What Modern Research Tells Us
A large body of research suggests that important aspects of brain development continue through adolescence and into the twenties. Development is gradual. There is no single age at which every person suddenly becomes fully mature.
This does not mean young adults cannot make decisions. Clearly they can. What it does challenge is the assumption that adulthood is completed overnight on a person’s eighteenth birthday.
Some researchers describe the period from the late teens into the twenties as a distinct life stage known as emerging adulthood. It is often characterised by increasing independence, responsibility and identity formation.
The important point is not where adulthood begins.
Why do we continue to talk about adulthood as though it starts overnight?
The Contradiction Between Responsibility and Protection – Why Maturity Seems to Change Depending on the Situation
Young adults are trusted with significant responsibilities.
They can work, pay tax, drive, enter contracts, accumulate debt, raise children, care for family members and make major life decisions.
Some people also support reducing the voting age to 16.
It increasingly appears that ages such as 16, 18, 21 and 65 are being asked to perform a remarkable number of different policy functions.
Are we sometimes confusing legal adulthood with developmental maturity?
At the same time, regulators have recognised that younger adults may be particularly vulnerable to commercial pressure in areas such as cosmetic surgery and other irreversible consumer decisions.
The same person may be capable of making informed decisions in one setting while being more vulnerable in another.
This raises an important question.
Is age really the issue, or is context the issue?
The Accountability Contradiction
The pressure on existing age categories is not confined to health, education or consumer protection. It is increasingly visible in criminal justice.
Public concern about serious youth violence has led to renewed debate about accountability, sentencing and when young offenders should face consequences more closely aligned with those applied to adults.
Many members of the public struggle to understand why age can significantly alter legal outcomes in cases involving serious violence, murder or repeated criminal offending.
At the same time, scientific research is increasingly used to explain developmental differences between adolescents and older adults.
What exactly do we mean when we say someone is old enough?
The purpose here is not to argue for harsher penalties or lower ages of criminal responsibility.
Rather, it highlights another tension within the framework itself.
In some settings, research is increasingly used to explain adolescent development and vulnerability. In others, society demands greater personal responsibility and accountability for serious actions.
Are we asking age categories to answer questions they were never designed to answer?
The same age categories are being used to determine voting rights, criminal responsibility, military service, consumer protection, financial independence, educational transitions and access to public services.
Yet these are fundamentally different questions requiring different forms of judgement, capability and responsibility.
Perhaps the problem is not any one age threshold. Perhaps the problem is that a handful of numbers have become responsible for organising almost every major transition in life.
Have we reached the point where a small number of age categories is being asked to perform too many different functions across modern society?
Longevity Is Changing Old Age – Why 65 No Longer Means What It Once Did
The same challenge exists at the other end of life.
Many people remain healthy, active and independent well beyond traditional retirement age.
Researchers increasingly distinguish between active later life, the transition into greater limitation and periods of frailty or dependency.
A 65-year-old and an 85-year-old may have very different capabilities, needs and levels of independence.
Has old age changed while our assumptions about it have remained largely the same?
Yet public debate often treats everyone above a certain age as part of the same category.
If age alone cannot explain the circumstances of an 18-year-old, it is difficult to see why it should explain the circumstances of a 65-year-old.
The modern lifespan is being stretched from both directions.
Development may continue for longer than once believed, while healthy and active life often lasts longer than previous generations experienced.
If we no longer assume all young people develop at the same rate, why do we assume all older people age at the same rate?
Responsibility Builds Resilience – The Difference Between Responsibility and Exploitation
The solution is not to protect young people from every challenge.
Responsibility can build capability.
Young people develop resilience through working, caring for others, managing money, supporting family members and contributing to their communities.
Many young carers demonstrate extraordinary responsibility long before reaching formal adulthood.
Are we sometimes protecting young people from the very experiences that help them grow?
Responsibility asks people to contribute.
Commercial exploitation is different.
It may identify insecurity, intensify dissatisfaction, create urgency and sell products, treatments or procedures as the solution.
Responsibility builds resilience.
Exploitation turns vulnerability into profit.
What is the difference between giving someone responsibility and exposing them to exploitation?
How Can We Update the System? – Practical Reforms for Modern Age Categories
Before deciding what the new numbers should be, perhaps we need to ask a more basic question:
Does the framework itself still reflect the realities of modern life?
If age categories underpin education, health, justice, consumer protection, retirement, social security and countless other areas of public life, then reviewing them should not be seen as a niche policy exercise.
It should be viewed as a whole-of-society discussion.
Possible reforms include:
- Regular reviews of major age-based policies against current scientific evidence.
- Greater transparency when governments decide not to act on new evidence.
- Better coordination between health, education, justice and consumer-protection agencies.
- Stronger monitoring of online health and medical advertising.
- Clear separation between public-health information and commercial promotion.
- Better evidence requirements for cosmetic, anti-ageing and longevity claims.
- More reporting on age-related outcomes across health and social policy.
- Later-life policies based more on capacity and function rather than age alone.
- A comprehensive review of whether ages such as 16, 18, 21 and 65 are being asked to perform too many different policy roles.
If we were designing these systems from scratch today, would we build them in the same way?
Conclusion
Age categories are useful. Governments, courts and public institutions need them to organise complex systems.
The question is whether the categories we rely upon still reflect the lives we are living.
Over the past few decades, our understanding of brain development has changed. Life expectancy has increased. Patterns of work, education and family life have changed. Medicine has also become increasingly commercialised.
The same can be said for longevity. Many of the assumptions that informed age-based frameworks were developed when life expectancy, workforce participation, education and family structures looked very different from today.
Yet many of the age thresholds that shape public policy remain surprisingly familiar.
The tensions within the framework are becoming harder to ignore. Young people are expected to work, pay tax, drive, care for others and make major decisions, while also being recognised as vulnerable in some settings. At the same time, public concern about serious youth violence has led to increasing demands for accountability and tougher consequences.
Older adults, meanwhile, are frequently grouped together despite enormous differences in health, independence and capacity.
Perhaps that is because reviewing age categories would force us to reconsider much larger questions about education, work, retirement, criminal responsibility, consumer protection and the role of government itself.
But avoiding the discussion does not make the issue disappear.
We have reviewed road-safety laws, tobacco policies and public-health frameworks as evidence evolved.
Why have we spent so little time questioning the numbers that define childhood, adulthood, ageing and dependency?
The purpose of this article is not to argue that age limits should be abolished, or that a new set of numbers would immediately solve these problems.
It is simply to ask whether frameworks developed for a different world still fit the one we live in today.
Perhaps the most important question is not what the new numbers should be.
It is whether the old ones still deserve the authority we give them.
If we were designing these frameworks today, knowing what we know about development, longevity and human behaviour, would we create the same categories?
Or are we still relying on them simply because they are the numbers we inherited?
That seems like a question worth asking.