'Loose Tooth Puberty': How Children's Brains Change at Age Six

When I got home, I was in a terrible mood. I don't remember what my mother asked me to do, but I clearly remember my response: "It's okay for you to be idle," I snapped, "while I had to go to that party!"

I then left furiously, leaving her speechless.

What had happened to her happy little boy?

She might have been less surprised if we lived in a German-speaking country. The word Wackelzahnpubertät—literally "loose-tooth puberty"—is used to describe how six-year-olds begin to display the moodiness characteristic of adolescence.

"Aggressive behavior, acts of rebellion and deep sadness are typical of the loose-tooth puberty," describes the German magazine Wunderkind.

Unlike actual puberty, loose-tooth puberty is not caused by hormonal changes.

It coincides with the beginning of "middle childhood" – a period of profound psychological change in which the brain lays the foundation for more mature thoughts and feelings.

"It's an important stage, in which the child is building their identity and trying to figure out who they are in relation to other people," says Evelyn Antony, a PhD candidate in psychology at Durham University in the United Kingdom.

"And their emotional universe is expanding too."

While childhood and adolescence are now well understood, middle childhood—which spans the ages of 6 to 12—has traditionally been neglected in scientific research.

Some psychologists even describe it as our "forgotten years."

"A lot of research focuses on the early years, when babies talk and walk, and then on adolescence, when there's a bit more rebelliousness," says Antony. "But less is known about middle childhood."

This has been changing recently, with new research identifying key characteristics of children's mental transformation at this stage of life.

The changes include a greater ability to reflect on their feelings and modify them when necessary, along with an "advanced theory of mind" that allows them to think more sophisticatedly about others' behavior and respond appropriately.

They also begin to master the fundamentals of rational inquiry and logical deduction, so that they can take more responsibility for their actions – which is why, in France, it is also known as " l'âge de raison " (the age of reason).

As the loose-tooth puberty concept illustrates, early middle childhood can be accompanied by some growing pains, but a deeper understanding of the neurological and psychological changes involved has offered new insights into the best ways to support a child along this journey.

Let's start with emotional regulation. By early childhood, most children have generally made significant progress in managing their feelings.

As newborns, they are completely dependent on surrounding adults to soothe their distress, which is often caused by physical stressors such as hunger, fatigue, or colic.

Over the next two years, they develop a larger emotional repertoire, including joy, anger, and fear, but they don't know how to regulate them—leading to those ear-shattering tantrums.

A child's developing language can provide some relief from these turmoils.

This is partly because it allows the child to express his or her needs more precisely, so that others can respond appropriately before frustration builds up.

There's no need to shout when you want more food, as you can simply say, "I'm hungry," and a caring adult will respond.

Words that express emotion can bring an even more immediate benefit. Naming an emotion appears to alter its neural response, engaging parts of the prefrontal cortex, an area involved in more abstract thinking, while calming the amygdala, the region responsible for sensing raw emotion.

By the time children reach five or six, however, they face new challenges that put their emotional understanding to the test, say Antony and other researchers.

Instead of relying on adults to guide all of their actions, they are expected to have greater independence—creating uncertainty and ambiguity that can lead to frustration.

They have to make friends on their own, live with people they don't like, and obey orders from adults.

At the same time, Antony points out, they are also developing a stronger sense of identity, with the need to define who they are in relation to others.

This transition can push a child's emotional regulation to the limit, which can result in the pubertal moods of the loose tooth, during which the child may become dejected and needy or erupt in sudden outbursts of anger.

Fortunately, children's brains adapt quickly to new demands.

This process often includes developing a broader vocabulary to describe and understand what they're feeling, including the concept of mixed emotions. (By age nine, most children can recognize that the bittersweet ending of Disney's The Little Mermaid is both happy and sad, for example.)

They also learn new strategies to modulate their feelings on their own, without relying on parents or teachers to calm them down.

Throughout middle childhood, people become more adept at using "cognitive reappraisal," for example—which involves altering the interpretation of an event to change its emotional impact.

If they're struggling with a task at school, for example, a child might start by thinking, "I can't do this," or "I'm stupid," or they might recognize their frustration as a stimulus to adopt a new strategy, which will likely calm their anger and increase their perseverance.

Much of the path to maturity comes from observing the adults around you.

"Children will learn how their parents deal with conflicts and different issues that arise in their lives," says Antony.

The child's social universe is also changing.

"Middle childhood is a period when 'reciprocal friendships' begin to develop," explains Simone Dobbelaar, a postdoctoral researcher in developmental and educational psychology at Leiden University in the Netherlands.

In other words, they begin to understand the give and take in relationships, which becomes a greater focus in their lives.

"Children begin to spend more time with their peers both inside and outside of the school context."

During middle childhood, children develop these social skills and mental perceptions to keep track of the thoughts and feelings of many people.

Imagine, for example, the story of a child, Nick, who wants to join a football team but doesn't believe he'll make it. The coach is aware of Nick's uncertainty but wants him on the team. After making his selection, does the coach know that Nick isn't yet aware of his decision to include him on the team? (The correct answer is yes.)

To answer this type of question, the child needs to consider what the coach knows about what Nick knows about the coach's opinion. In other words, they are considering one person's theory of mind against another's theory of mind, which is known as a "recursive" process.

This reasoning is important for tracking who knows a secret, spreading gossip on the playground, and recognizing when someone might be "double-bluffing" to outsmart us in a game—but until recently, psychologists weren't clear about when it first appears in childhood.

To answer this question, Christopher Osterhaus of the University of Vechta in Germany and Susanne Koerber of the University of Freiburg recruited 161 five-year-old children and measured their performance on various theory-of-mind tasks over the next five years.

Analyzing the data, they found a "sharp increase" in their abilities between the ages of five and seven, before performance began to plateau.

This suggests there was some kind of conceptual leap, says Osterhaus: "If it was just [them becoming gradually better at handling] the complexity of the task, you would expect a more steady increase."

This mental leap has immediate and positive consequences for children's social lives and well-being, the research indicates.

"We found that the greater the social reasoning, the lower the feelings of loneliness," Osterhaus notes.

"Maybe they're finding it easier to make friends or engage in deeper friendships."

In this sense, Dobbelaar's research suggests that increased sensitivity is linked to more prosocial behaviors, such as acting especially kindly toward someone who feels excluded.

To study this, she conducted an experiment that mimicked the kind of petty bullying that is, unfortunately, common on many playgrounds .

The experiment involved a simple video game called Cyberball , in which four players pass a ball between each other.

Unbeknownst to the participants, the other three players were controlled by the computer, two of which could be programmed to exclude the third robot, not giving it a chance to catch and throw the ball.

Younger participants seemed less sensitive to injustice. As they moved from middle childhood to early adolescence, however, many participants began compensating for the other players' cruel behavior by using their own turns to pass the ball to the robot that was being ignored—showing a small sign of solidarity with the victim.

Using functional MRI scans of the children's brains, Dobbelaar and his colleagues found that this was associated with some characteristic changes in neural activity, suggesting a reduced focus on themselves—and, presumably, an increased focus on others.

"This may be due to increased perspective-taking," she says, as the children's developing brains were able to consider the "bullied robot's" feelings.

Despite these many benefits, sophisticated social reasoning can have a downside: increased self-judgment and insecurity.

Consider a study on the "affinity gap," which describes our tendency to underestimate how much another person likes us compared to how much we like them.

A recent study by Wouter Wolf, now at Utrecht University in the Netherlands, found that the affinity gap first appears at age five and increases steadily throughout middle childhood.

The more attuned we become to the mental lives of others, it seems, the more we begin to worry that their view of us isn't as friendly and positive as we'd like.

I suspect this might explain my bad mood at the party; it was my first brush with self-judgment and loneliness—and I didn't yet have the words to express why I felt sad and angry, or the skills to bridge the affinity gap and build new friendships with people I didn't know well.

Adults in a child's life can facilitate the development of these skills through frequent conversations.

Antony, for example, points to research demonstrating the power of "emotional coaching." This involves listening to the child without judgment, validating what they're feeling, and then suggesting ways to move forward in a more positive way.

"It's not about the adult trying to fix everything for her, but rather guiding her through this process of managing her emotions," she says.

An adult can encourage cognitive reappraisal, for example, by showing the child how an initially upsetting event can be interpreted in different ways.

The child can then apply this when they are upset again, protecting them from future stress.

A parent or guardian can also talk about social dilemmas—whether in real life or fiction.

"You can ask them: Why did this person react that way? Why did they say that?" Osterhaus explains.

This helps them think more carefully about other people's mental states, he says, which should encourage a more advanced theory of mind.

Sometimes the two approaches converge naturally. If a child is upset because their best friend was rude, you can encourage them to question the possible reasons for the unpleasant behavior.

Maybe he was tired or having a bad day; it was nothing personal, and the episode can therefore be met with compassion rather than anger.

Like any skill worth learning, these require constant practice.

In many of these moments, however, the child will be well equipped to understand his own mind and the minds of others, guiding him far beyond "loose-tooth puberty" into the adventures of adolescence and beyond.

*David Robson is an award-winning science writer and author. His latest book, "The Laws of Connection: 13 Social Strategies That Will Transform Your Life," was published by Canongate (UK) and Pegasus Books (US and Canada) in June 2024.