'Wobbly-tooth puberty': How children's brains change at six-years-old

BBC News

13-07-2025

Long neglected by science, "middle childhood" between the age of six and 12 years old is a transformative period preparing children for growing up. Here's what's going on in their heads during this turbulent time plus how to navigate it.
My first small act of rebellion came when I was around six years old. I'd just been to a birthday party in the local village hall, with a bunch of children I barely knew. They'd all arrived with their friends, and I felt shy and left out.
By the time I returned home, I was in the foulest of moods. I don't remember what my mum asked me to do, but I can clearly recall my response. "It's alright for you, lazing about," I snapped, "while I had to go to that party!"
I then stormed off, leaving her speechless. What had happened to her sunny little boy?
She might have been less surprised if we had lived in German-speaking country. The word Wackelzahnpubertät – literally "wobbly-tooth puberty" – describes how six-year-olds start to show the bad moods characteristic of adolescence. "Aggressive behaviour, rebellious activism, and deep sadness are typical of the wobbly-tooth puberty," is how the German magazine Wunderkind puts it. (Read on to the bottom of this piece for some tips on how parents can deal with this change in behaviour.)
Unlike the real deal, wobbly-tooth puberty is not driven by hormonal changes. Instead, it coincides with the start of "middle childhood" – a period of profound psychological change in which the brain lays the foundations for more mature thoughts and feelings. "It is a really key stage in which a child is constructing their identity, and they're trying to figure out who they are in relation to other people," says Evelyn Antony, a doctoral student in psychology at Durham University in the UK. "And their emotional world is expanding as well."
Whereas infancy and adolescence are now well-understood, middle childhood – which spans ages six to 12 – has been sorely neglected in scientific research. Some psychologists go as far as to describe it as our "forgotten years". "A lot of the research focuses on the early years, when babies are talking and walking, and then in adolescence when you have a bit more of rebellion," says Antony. "But there's less known about middle childhood."
That is now changing, with new research identifying the core characteristics of children's mental metamorphosis. The transformation includes a greater capacity to reflect on their feelings and modify them when needed, along with an "advanced theory of mind" that allows them to think more sophisticatedly about others' behaviours and respond appropriately. They also begin master the basics of rational enquiry 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.
As the concept of wobbly-tooth puberty illustrates, the onset of middle childhood may be accompanied by some growing pains, but a deeper understanding of the neurological and psychological changes involved is offering new insights on the best ways to support a child throughout the journey.
Wobbly-tooth puberty
Let's begin with emotional regulation. By the start of middle childhood, most children will have already made some huge advances in their capacity to control their feelings. As a newborn, they were completely dependent on the adults around them to soothe their anguish, which is most often caused by physical stressors like hunger, fatigue, or colic. Over the next couple of years, they develop a greater emotional repertoire that includes joy as well as anger and fear, but they do not know how to regulate them – leading to those eardrum-exploding tantrums.A child's burgeoning language can provide some relief from those maelstroms. That's partly because it allows the child to express their needs more precisely, so that others can respond appropriately before the frustration builds up. There is no need to scream when you want more food if you can simply say "I'm hungry", and a caring adult responds. Emotion words may bring an even more immediate benefit, however. Naming an emotion appears to change its neural response, engaging parts of the prefrontal cortex, which is an area involved in more abstract thought, while soothing the amygdala, the region involved in the sensation of the raw emotion.
As a child reaches five or six, however, they face new challenges that put their emotional understanding to the test, Antony and other researchers say. Rather than relying on adults to guide their every action, they are expected to have greater independence – creating uncertainty and ambiguity that may breed frustration.
They must make friendships by themselves, get along with people they don't like, and obey adults' rules. As Antony points out, they are also developing a stronger sense of self, with a need to define who they are against others.
This transition can stretch a child's emotional regulation to its limits, which may result in the moods of wobbly-tooth puberty, during which the child may become downcast and clingy, or explode in sudden bursts of anger.
Fortunately, children's brains quickly catch up with the new demands. This process usually includes developing a larger vocabulary to describe and understand what they are feeling, including the concept of mixed emotions. (By age nine, most children can recognise that the bittersweet ending of Disney's The Little Mermaid is both happy and sad, for example.)
They also learn new strategies to change how they are feeling by themselves, without relying on a parent or teacher to soothe them. Throughout middle childhood, people become more adept at using "cognitive reappraisal", for instance – which involves altering one's interpretation of an event to shift its emotional impact. If they are struggling with a task at school, for instance, a child might start out by thinking "I can't do this" or "I'm stupid" – or they might recognise their frustration as a prompt to adopt a new strategy, which is likely to calm their anger and enhance their perseverance.
Much of their path to maturity comes from observing the adults around them. "Children will learn how their parents deal with conflict and different issues that come up in their lives," says Antony.
Seeking friendship
The child's social world is also changing. "Middle childhood is a period where 'reciprocal friendships' start to develop," explains Simone Dobbelaar, a post-doctoral 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 become a greater focus in their lives. "Children start to spend more time with their peers in and outside of the school context."
Over middle childhood, individuals build on these social skills and mental insights to keep track of many people's thoughts and feelings.
Imagine, for instance, a story about a child, Nick, who wants to be on a football team, but doesn't think he's going to make the cut. The coach is aware of Nick's uncertainty, but wants him on the team. Once he has made 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 kind of question, a child has 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 about another person's theory of mind, which is known as a "recursive" process.
Such reasoning is important for keeping track of who knows a secret, passing gossip around the playground, and recognising when someone might be "double bluffing" to fool us in a game – but until recently, psychologists hadn't been clear when it first emerged in childhood.
To find out, Christopher Osterhaus at the University of Vechta, and Susanne Koerber at the University of Freiburg, recruited 161 five-year-olds and measured their performance on various theory-of-mind tasks over the next five years. Analysing the data, they found a "steep increase" in their abilities between five and seven, before their performance started to plateau. This suggests that it involved some kind of conceptual leap, he says: "If it was just [them getting gradually better at tackling] the complexity of the task, then you would expect a steadier increase."
This mental leap has immediate, positive consequences for children's social life and wellbeing, research suggests. "We find that the higher their social reasoning, the lower the feelings of loneliness," says Osterhaus. "Maybe they're finding it easier to make friendships or to engage in deeper friendships."
Along these lines, Dobbelaar's research suggests that enhanced sensitivity is linked with more prosocial behaviour, such as acting especially kindly to someone who feels excluded. To study this, she set up an experiment that mimicked the kind of petty bullying that is sadly only too common in many playgrounds. (Read more on a proven way for schools to stop bullying.)
The experiment involved a simple videogame called Cyberball, in which four players pass a ball between themselves. Unbeknown to the participants, the three other players were all controlled by the computer, two of which could be programmed to exclude the third bot by never giving them a turn to catch and throw the ball.
Younger participants appeared to be less sensitive to injustice. As they passed through middle childhood and into early adolescence, however, many of the participants started to compensate for the other players' mean behaviour by using their own turns to pass the ball to the bot that was being overlooked – providing a small sign of solidarity with the victim.
Using fMRI scans of the children's brains, Dobbelaar and her colleagues found that this was associated with some characteristic changes in neural activity, which suggested a reduced focus on themselves – and, presumably, an increased focus on others. "It could be due to increases in perspective-taking skills," she says, as the children's developing brains were able to consider the feelings of the "bullied bot'.
The beginning of self-doubt
Despite these many benefits, sophisticated social reasoning can come with a downside: greater self-consciousness and self-doubt. Consider a study of the "liking 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, who is now based at Utrecht University, found that the liking gap first emerges at age five and increases steadily over middle childhood. The more attuned we become to other's mental lives, it seems, the more we start to worry that their view of us is not as friendly and positive as we'd like it to be.
I suspect this may explain my bad mood at the party; it was my first taste of self-consciousness and loneliness – and I didn't yet have the words to express why I felt sad and angry, or the skills to overcome the liking gap and build new friendships with people I didn't know well.
The power of a chat
The adults in a child's life can ease the development of these skills through regular conversations. Antony, for instance, points to research demonstrating the power of "emotion coaching". This involves listening to the child without judgement, validating what they are feeling, and then suggesting ways that they move on more positively. "It's not about the adult trying to fix everything for them, but guiding them through this process of managing their emotions," she says. An adult may encourage cognitive reappraisal, for instance, by showing the child how an initially upsetting event could be interpreted in different ways. The child may then apply this when are next upset, arming them against future stresses.
A parent or guardian may also talk through social dilemmas – either in real life or in fiction. "You might ask them, why did this person react that way? Why did they say it?" says Osterhaus. This helps them to think more carefully about other people's mental states, he says, which should encourage more advanced theory of mind.
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Sometimes, the two approaches will naturally converge. If a child is shaken because their best friend has been rude, you might encourage them to question the potential reasons for the nasty behaviour. Perhaps they were tired or having a bad day; it was nothing personal and can be treated with compassion rather than anger.
Like any skills worth learning, these abilities need constant practice. Over many such moments, however, the child will be well-equipped to understand their own and others' minds, guiding them well past their "wobbly-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 (USA & Canada) in June 2024. He is @davidarobson on Instagram and Threads and writes the 60-Second Psychology newsletter on Substack.
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