On the phone, a four-year-old holds her new drawing up to the receiver: 'Grandma, do you like it?' She doesn't yet realise that Grandma can't see it. A few years later the same girl argues with a friend about the rules of a game, gives reasons and sometimes changes her mind. These two scenes show a key discovery of the science of intelligence: thinking does not mature in isolation, but grows in conversation and shared work.
Piaget: from obedience to cooperation
Jean Piaget (1896–1980) is best known for his stages of mental development, but in The Psychology of Intelligence (1947) he gave a whole chapter to social factors. Until about the age of 7–8, he observed, children's thinking is marked by egocentrism. This is not selfishness: a young child simply finds it hard to step outside their own point of view. They may mix up the right hand of a person facing them, or assume that whatever they know, everyone knows.
Curiously, this egocentrism goes together with simply accepting whatever adults say. A small child can repeat a correct rule word for word without knowing why it is true. For Piaget, repeating is not yet reasoning. Reasoning needs reciprocity: each person explains their own view and checks the other's.
So, in Piaget's view, logic grows out of cooperation and discussion between equals, not out of pressure. Pressure produces obedience; an argument with a friend makes each side give reasons and stay consistent. Piaget even called logic 'a morality of thought': like a fair game of chess, clear thinking needs rules that everyone accepts. Teenagers, in turn, test their dreams and ideals in debates with their peers.
Vygotsky: the tools of culture
Lev Vygotsky (1896–1934), born in the same year as Piaget, gave the social side even more weight. A child's mind, he argued, develops through tools created by culture: above all language, but also numbers, writing, drawings and maps. A new mental skill first appears in activity shared with other people, and only later moves inward and becomes the child's own.
Preschoolers often talk to themselves while they play or build: 'This one goes here... no, here.' Vygotsky saw such private speech as a sign of thinking: words are becoming a tool for planning. Over the years it grows quieter and turns into inner speech, the silent voice we all think with.
In Thinking and Speech (1934) Vygotsky described the zone of proximal development: the distance between what a child can do alone and what they can do with help. Teaching works best inside this zone, at the next step. Piaget valued debate between equals, Vygotsky the help of a more experienced partner; today the two views are seen as complementary.
Scaffolding: help that steps back
In 1976 Wood, Bruner and Ross studied how an adult helps a young child solve a problem, and they called this kind of help scaffolding. Like scaffolding around a new building, it supports the work while it is needed and then comes down. Good scaffolding keeps the child interested, breaks the task into small steps, keeps the goal in view and eases frustration. Then the adult gradually steps back: with too much help the child learns nothing, and with too little they give up.
Soviet psychology: abilities form in activity
Soviet psychologists put activity at the centre of mental development. Alexei Leontiev stressed that specifically human abilities are not given ready-made at birth: they form as a child, through their own activity, masters the tools and achievements of culture, from language and counting to books and instruments. Inborn qualities such as good hearing and a healthy brain are necessary conditions, and today scientists agree that biology and experience both play a part.
In his 1947 book on musical abilities, Boris Teplov showed that abilities develop within a particular activity and that different abilities can compensate for one another. Pyotr Galperin described how a new mental action is first done with the hands on real objects, then spoken aloud, and only then performed silently in the mind. A child who counts on their fingers, then aloud and finally in their head is following exactly this path.
What this means in practice
- Talk and listen: at the table, on the way to school, before bed. Ask your child's opinion and hear them out.
- Ask 'How do you know?', not as a test but as an invitation to give reasons. In time, children start asking themselves the same question.
- Let siblings and friends argue respectfully: a dispute over the rules of a game is a lesson in logic. Teach them to use reasons, not raised voices.
- Aim one step ahead: choose tasks slightly beyond what your child can do alone. Do them together first, then give hints, then step back.
- Let your child learn alongside a skilled adult: cooking, mending or gardening together, with each step talked through.
- Don't silence a child who talks to themselves over homework: they are thinking aloud.
Teachers can use the same ideas through pair work, class discussion and asking pupils to explain a solution to a classmate.