A Few Things Writers Need To Know About Maturity & Mental Development

Mental maturity is a physical process. Yes, really. The human brain doesn't finish developing until the age of 25. At the age of eighteen, the age of being a legal adult in many countries, the prefrontal cortex is still only half-developed. For those unfamiliar, the prefrontal cortex is the part of your brain that helps you assess risks and control your emotions and impulses.

But this doesn't mean people should be treated as children until the age of 25. The maturation process happens on a continuum, not overnight. Someone at the age of 23 is developmentally close enough to a 25 year old that there's no serious mental disparity between them. On the other hand, the disparity between a 17 year old and a 24 year old is significantly wider, and they should absolutely not be treated as being on the same level simply because they both haven't finished developing. And obviously, people are often fully capable of living independently in their late teens and early twenties, so there's no reason why they shouldn't. (Yes, they are more likely to take risks, but these risks help them learn things for themselves and help them find their place in an adult world.)

No, going through hardship does not accelerate someone's maturity. I've seen people insist that their characters should be considered "practically adults" because they've gone through terrible situations that forced them to learn adult skills as a matter of survival. But simply being able to act like an adult sometimes does not make one an adult, because one will still have the emotional needs and cravings of a child or teen, and will suffer psychological harm if these needs and cravings go unmet. Furthermore, traumatic experiences can even hinder the development of the prefrontal cortex, leaving the skills associated with it permanently underdeveloped.

Past life memories wouldn't accelerate maturity, either. A child with the memories of a past life as an adult would not have "the mind of an adult." This child would simply have an adult's memories in a child's brain. Again, the development of the brain is a purely physical process, and simply having an adult's knowledge would not accelerate it.

Cognitive empathy also develops during adolescence. It's somewhat different between girls and boys, but the ability to put oneself into another person's shoes develops and strengthens quite a bit during adolescence. (And yes, this is associated with the development of the prefrontal cortex.)

Being told that you're "mature for your age" rarely means as much as you might think. When adults refer to teens and children being "mature for their age," what they're often referring to is the fact that these children are quiet and complacent and/or agree with whatever the adults say without argument. However, increased willfulness and independent thinking is a healthy and normal part of growing up and becoming an independent, autonomous adult. Adults who remain quiet and complacent or just agree with everyone else, on the other hand, tend to be doormats. And children might be quiet simply because they're shy, but it doesn't make them mature - it just makes them shy. Sometimes they refer to the child having academic interests, but this doesn't mean that the child is actually mature - all it means is that the child has academic interests. (And conversely, this means that loud, rambunctious children are not "immature." They're just perfectly normal children.)

Wanting to associate with adults rather than one's peers doesn't make one mature, either. There are a number of reasons that one might prefer associating with older people rather than one's peers, which have nothing to do with "maturity." For example, a younger person can potentially find the rowdy and rambunctious behavior commonly found in younger people to be confusing or overstimulating, and might find adults, who tend to be more placid, easier to get along with and talk to. It can also happen that one's peers simply have different interests and priorities, whereas it's easier to find adults who share one's own interests.

High levels of intelligence do not equal maturity. Very intelligent children can sound more mature simply because they have bigger and more sophisticated vocabularies, and/or because they understand more topics in greater depth than their peers. However, the prefrontal cortexes of genius children are still in development, and as such they still have less emotional control, impulse control, foresight, etc. than someone older. Furthermore, they still have the same emotional needs and desires as any other child - IE, to have caring, supportive adults to look after and guide them, and to engage in recreational and creative play moreso than adults.

"People used to get married and have children at the age of fourteen!" is not a counterargument to any of this. While it's technically true that some people have done this, whether it was actually good for them is another matter entirely. In fact, this type of thing is linked to higher higher childbearing-related risks and a greater risk of developing mental illness.

Someone can exhibit mature-seeming behaviors early on, but fail to progress beyond that point and so eventually fall behind. For example, someone can exhibit behaviors at the age of fourteen that seem mature for a fourteen year old, but then fail to progress very far beyond that point... and at the age of twenty three, behave in a manner that would be more appropriate for a sixteen or seventeen-year-old. So, those who were told that they were "mature for their age" when they were several years younger would do well to remember that their behavior now might not be as "mature" as they think.

Conversely, just because someone exhibits some immature-seeming behaviors later on, doesn't mean this person has a "child-like mentality" or somesuch. Someone can sleep with stuffed animals and watch children's cartoons, and still have age-appropriate levels of the aforementioned traits associated with the prefrontal cortex. And if an adult is in the habit of reading sympathetic human traits into inanimate objects, it doesn't necessarily mean that this person has a "child-like imagination" - it might just mean that this person has higher-than-average amounts of empathy.

Someone being a teenager is not a good reason to write off that person's feelings and opinions. While teens are more prone to making errors in judgment because they don't always have as many facts as older peers and because they tend to be more impulsive, a sixteen year old can do perfectly fine when it comes to making decisions and conclusions that require time to think about. And it must always be remembered that it's possible for teenagers to have insight into a particular situation that adults may lack. (For example, the experience of being a teenage student in an environment that's far different from where current adults spent their teen years.)

What the maturation process tends to look like in late adolescence. In my observation, people tend to desire some form of parental care up until around their mid-twenties. This usually takes the form of wanting a parental figure to give them guidance and emotional support - without butting in and trying to run their lives. If not an actual parent, then an older sibling, senior officer, or mentor can fill the role. (It must also be noted that even if they are both of age and unrelated to each other, it's still inappropriate them to have a romantic relationship with each other due to the power imbalances and conflicts of interest involved.) At this point their sense of identity tends to solidify, and by the time they're done they usually aren't left feeling bewildered and confused as to what they are and what they're meant for anymore. (There's no magical moment where they instantly figure it out. It just sort of gradually coalesces.) And they usually become more content to settle down and stay in one place, and are inclined to focus more on the world and community immediately around them.

What this means for fantastic scenarios. So let's say we have a teenage character who has actually reincarnated over many lifetimes. This character might have a soul that's thousands of years old, but right now this character still has the brain of a teenager, and will be subjected to all that entails. Ergo, this character can't reasonably be expected to act like an adult, let alone serve in an adult capacity. For another example, if we had a vampire who was turned as a teenager, this vampire would have the mind of a teenager forever - which would ultimately be a disadvantage.