Introduction

Most countries recognize 18 as the start of adulthood by granting various freedoms and privileges. However, is age the best way to measure maturity? This question has sparked debates, especially when it comes to voting rights. Some argue that the voting age should be lowered to 16, while others firmly disagree, believing that 16-year-olds are not mature enough to make decisions with national consequences.

Questioning Age Limits of Adulthood

It’s worth noting that some countries have lowered the voting age to 16, and cultural coming-of-age ceremonies are often celebrated at different ages. As there seems to be no consensus on exactly when we reach maturity, perhaps science can give us a clearer answer.

Defining Adulthood Through Brain Development

One way neuroscientists have looked to define adulthood is by when the brain is fully grown. Brain development involves two trajectories. First, there’s a reduction in gray matter, which consists of cells and connections that facilitate communication at short ranges, creating dense, information-processing hubs. This gray matter reduction coincides with an increase in white matter, which refers to connections that are myelinated, allowing for fast far-range communication between information hubs. Imaging studies show that white and gray matter volumes undergo drastic changes during adolescence, and continuing through your twenties.

Adulthood and Cognitive Development

Another way scientists have tried to define adulthood is by measuring cognitive development—when are you able to learn and complete mental tasks at the same efficiency as older adults? By this definition, adulthood may begin as early as 16, as teens perform just as well on tests that assess reasoning, problem-solving, and critical thinking. However, teens may be more susceptible to external pressures.

The Influence of Emotional and Social Elements

Studies show that when performing risk-taking and self-control-related tasks, 18 to 21-year-olds behave much like older adults. But when these tests include an emotional element or a social element, different patterns emerge. Under these influences, 18 to 21-year-olds tend to behave more like younger teens, and their brains show younger-teen-like patterns of activity. This suggests that during your teens and early twenties, your brain is wired to place more value and attention on social and emotional elements.

Implications for the Judicial System

For this reason, many scientists argue that judicial systems should expand juvenile courts to include those in their late teens and early twenties, as current systems fail to recognize how the emerging adult brain is still changing.

Conclusion

So when are you actually an adult? As you can see, there is no exact age or moment in development that we can point to. Instead, neuroscience suggests that there are waves of maturity. As different brain regions and mental abilities mature at different times, so do different adult-like states and behaviors. Not everyone will reach each wave of maturity at the same age. Each person’s journey to adulthood is unique, and influenced by genetics, environment, and experience.