The age of adulthood: discussing maturity and brain science

00:06 Most countries recognize 18 as the start of adulthood00:10 by granting various freedoms and privileges.00:13 But is age the best way to measure maturity?00:17 I was born 12:05 AM on November 6th—00:20 5 minutes short of being eligible to vote in the election tomorrow.00:24 Meanwhile, your big brother— yours truly—00:27 was born 15 minutes earlier, so I can vote.00:30 It's arbitrary and unfair!00:33 The voting age should be lowered to 16!00:37 I firmly disagree!00:38 No way 16-year-olds are mature enough to make decisions with national consequences.00:42 I'm eligible and I don't even know who's running.00:46 Meanwhile, I know the candidates inside and out.00:50 She's obsessed with politics.00:52 Exactly! If 16-year-olds aren't mature enough to vote,00:55 then by that same logic, they shouldn't be allowed to drive.00:58 I firmly disagree! I'm an excellent driver!01:01 And I've never gotten a ticket, unlike some people.01:04 That's so unfair! That stop sign was hidden by a tree.01:08 I think you both make valid points.01:10 And questioning the age limits of adulthood is well warranted.01:14 Some countries have lowered the voting age to 16,01:17 and cultural coming-of-age ceremonies are often celebrated at different ages.01:21 As there seems to be no consensus on exactly when we reach maturity,01:26 perhaps science can give us a clearer answer.01:30 One way neuroscientists have looked to define adulthood01:33 is by when the brain is fully grown.01:36 Brain development involves two trajectories.01:39 First, there's a reduction in gray matter.01:42 Gray matter consists of cells and connections01:44 that facilitate communication at short ranges,01:47 creating dense, information-processing hubs.01:51 While a reduction may seem like a bad thing,01:53 what's happening is a selective pruning.01:56 Connections that are used are kept and strengthened,01:59 while under-used ones are weeded away,02:02 creating a brain that is both fine-tuned to its environment and energy efficient.02:08 This gray matter reduction coincides with an increase in white matter.02:13 White matter refers to connections that are myelinated,02:16 coated in a layer of insulation,02:18 allowing for fast far-range communication between information hubs.02:23 For example, these paths connect regions that signal02:25 the pleasure of immediate reward with regions that help us plan ahead,02:30 allowing us to make more balanced, forward-thinking decisions.02:34 Imaging studies show that white and gray matter volumes02:37 undergo drastic changes during adolescence,02:39 and continuing through your twenties.02:42 But the brain's journey is far from finished,02:44 as various experiences continue to reshape its connections02:48 throughout your lifetime.02:49 So brain structure alone may not give us our answer.02:53 Another way scientists have tried to define adulthood02:56 is by measuring cognitive development—02:59 when are you able to learn and complete mental tasks03:02 at the same efficiency as older adults?03:05 By this definition, adulthood may begin as early as 16,03:08 as teens perform just as well on tests03:10 that assess reasoning, problem-solving and critical thinking.03:14 Though capable of making smart, well-informed decisions,03:17 teens may be more susceptible to external pressures.03:21 Studies show that when performing risk- taking and self-control related tasks,03:26 18 to 21 year olds behave much like older adults.03:29 But when these tests include an emotional element—03:32 such as utilizing self-control when identifying fearful faces—03:36 or a social element—03:37 such as making a decision in the presence of a friend—03:40 different patterns emerge.03:42 Under these influences, 18 to 21 year olds tend to behave more like younger teens,03:47 and their brains show younger-teen-like patterns of activity.03:51 In other words, during your teens and early twenties,03:54 your brain is wired to place more value and attention03:57 on social and emotional elements.04:00 This allows emerging adults to better explore their identities04:03 and connect with others,04:04 but may also create more vulnerability to negative peer influence04:08 and rash heat of the moment decisions.04:11 For this reason, many scientists argue that judicial systems04:15 should expand juvenile courts to include04:17 those in their late teens and early twenties,04:20 as current systems fail to recognize04:22 how the emerging adult brain is still changing.04:25 So when are you actually an adult?04:27 As you can see, there is no exact age or moment04:30 in development that we can point to.04:32 Instead, neuroscience suggests that there are waves of maturity.04:36 As different brain regions and mental abilities mature at different times,04:40 so do different adult-like states and behaviors.04:44 Not everyone will reach each wave of maturity at the same age.04:47 Each person's journey to adulthood is unique,04:50 influenced by genetics, environment, and experience.