Child development milestones mark levels of cognitive competence
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Child development milestones

By Cynthia Lightfoot and , | June 2018 

Child development milestones or stages mark the attainment of particular levels of cognitive competence. They vary widely among children.

Child development milestones or stages mark the attainment of particular levels of cognitive competence. This emerges through physical maturation and the past experiences of the child. All children between two and five who develop normally within their culture acquire a number of basic skills and abilities.

Some disagree with the very idea that there are distinct child development milestones. Children develop in such diverse ways, particularly if we look across different cultures. Even in a single culture, children develop differently, and can perform more or less competently within a given stage. Those who disagree with the idea of child development milestones see development as a gradual and uneven growth of various psychological mechanisms.

Variation in child development milestones: familiarity and culture

Variation in competence between child development milestones is strongly related to familiarity with a situation. In one experiment, conducted by psychologist Jean Piaget, preschool children were shown a diorama of three mountains, each with a distinctive object on top. The children were unable to say what the scene would look like to a doll sitting on the other side of it.

Child development milestones - familiarity and culture

But later in 1975, another researcher, Helen Borke, found children of the same age could achieve this task if the landmarks were familiar objects – farms with animals, people, buildings and trees – and if the doll were replaced by Grover, a character from Sesame Street, driving around in a car.

What children learn in different cultures is extremely varied: using technology in the USA, finding water-bearing roots in the Kalahari desert, dancing in Bali, skiing and skating in Norway, and so on. Culture and environment determine what objects are available to learn with, what activities are frequent and normal, what people do together and what children learn at school.

The brain developments that underpin early child development milestones

At two years, the brain is 80% of its full adult weight; by five, it reaches 90%.

Three key brain development processes occur during these years:

  • Improvement in the efficiency and speed of connections. Between the ages of 2 and 5, myelination is most prominent in the frontal cortex, which is important for things like planning and regulating behavior.
  • Increase in length and branching of neurons connecting different parts of the brain.
  • Synaptic pruning, whereby nonfunctional synapses die off.

Overall, the brain remains relatively immature during this period. The development of parts of the brain associated with memory (the hippocampus and the frontal cortex) is still incomplete. This may help explain why children of this age find it difficult to keep several things in mind at once.

Different parts of the brain develop unevenly. One illustration of this involves “scale errors.” A fully mature person can seamlessly integrate two different brain activities – the perception of scale or size, and actions towards an object. If these two abilities are not integrated, as in children up to around two and a half years, a child may try to do impossible things, like pushing a big peg into a small hole, or sitting in a doll’s chair or toy car. They cannot match their perception of size with their actions towards the object.

Brain development, like child development overall, comes with practice – it depends on experience. This it is highly influenced by the specific experiences afforded by different cultures. Brain areas associated with certain spatial abilities develop in response to children’s involvement in hunting or weaving. Language areas undergo increased growth where verbal expression is frequent and important. Brain processes associated with attention and memory are highly developed when children learn music.

Motor stages of development

A two-year-old and a five-year-old have enormously different physical abilities. During this period, children learn new gross motor skills. For example, they may learn to ride a tricycle and later a scooter, throw a ball overhand and climb. Fine motor skills also develop: drawing, dressing, tying shoes.

Motor stages of early childhood

Age in years Gross motor skills Fine motor skills
Two Walks well


Goes up and down stairs alone

Kicks ball

Uses spoon and fork

Turns pages of a book

Imitates circular stroke

Builds tower of six cubes

Three Runs well


Rides a tricycle

Stands on one foot briefly

Feeds self well

Puts on shoes and socks

Unbuttons and buttons clothing

Builds a tower of 10 blocks

Four Skips

Executes standing broad jump

Throws ball overhand

Other examples of high motor drive

Draws a person

Cuts with scissors (not well)

Dresses self well

Washes and dries face

Five Hops and skips

Has good balance


Rides a scooter

Dresses without help

Prints simple letters

Ties shoes

Cognitive child development milestones

According to Piaget, children between the ages of two and six are at the “pre-operational” stage.

At this stage, children can

  • represent reality to themselves through the use of symbols, including mental images, words, and gestures;
  • think about objects and events even when these things are not actually present;
  • struggle to distinguish their point of view from that of others;
  • become easily captured by surface appearances; and
  • be confused about causal relations.

A key characteristic of the pre-operational stage of development is overcoming “centration,” which is the tendency to be “captured” by a single feature of a situation to the exclusion of all others. A child can be shown two balls, both with red stripes but where the other color is different. Before centration is overcome, children will, when asked to “point to the red ball”, confidently pick one at random and stick to their choice with confidence.

Child development milestones - pre-operational

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Piaget called the ability to pull away from one aspect of a problem and consider multiple aspects simultaneously “decentration,” which leads directly to objectivity. Piaget regarded this as a major stage in child cognitive development.

Early cognitive development stage: learning a different person’s perspective

Egocentrism is the tendency to center things on oneself. Children might believe that the moon follows them around when they walk at night. They won’t understand this can’t be true because another child walking in the other direction will have the same experience.

The mountain diorama test described above is a test of egocentrism: can the child understand a different person’s perspective?

The development of an understanding of others’ perspectives is called “theory of mind,” demonstrated by the false belief test. In this test, the child is presented with the story of Maxi, who returns home from shopping with his mother and, before going out to play, puts his chocolate away. While he is outside, his mother moves the chocolate. When Maxi gets hungry and returns for his chocolate, children are asked, where will he look for it and/or were will he think it is? A five-year-old will know immediately that Maxi will look for it where he left it, but a three-year-old will incorrectly claim that Maxi will look for it where Maxi’s mother put it.

Early cognitive development stage: learning the difference between appearance and reality

Two-and-a-half-year-olds can be frightened by someone putting a witch or dragon mask on. They have difficulty distinguishing between appearance and reality.

For example, researchers have presented children with objects whose appearance is deceptive: a sponge that looks like a stone, a stone that looks like an egg, a bar of soap that looks like a block. Children are asked to name the objects before touching them, and then they are given the objects to touch so they discover their true nature. Then they are asked what the object looks like. Three-year-olds change their minds and will now insist that the stone-like sponge looks like a sponge, the stone-like egg looks like an egg and the block-like soap looks like soap. Five-year-olds will not, because they are able to differentiate between appearance and reality.

Early cognitive development stage: learning cause and effect

At this stage of development, children learn more about cause and effect. Four- to five-year olds typically ask endless questions about cause and effect: “Why is the sky blue?” “Where do babies come from?” “What makes clouds?” In contrast, Piaget described his own daughter at three years confusing cause and effect after missing an afternoon nap: “I haven’t had a nap, so it isn’t afternoon.”

Children at this stage of development show more attention to confusing situations where they cannot deduce cause and effect. They start to search for new explanations. In one experiment, a blue object is shown to activate a light box and turn it on, while a green object does not. Once they have learned this, children particularly take note when the experiment is rigged and the blue and green objects start to do unexpected things.

Early cognitive development stage: distinguishing between living and nonliving things

The distinction between animate and inanimate things is a complex capacity. It involves being able to understand quite abstract biological processes – growth, the ability to move independently, the possession of internal parts and internal thoughts. In computer screen tests, four-year-olds show an emerging but incomplete ability to categorise objects between living and nonliving.

child development milestones - early cognitive development

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Some scientists believe this ability is a specific and separate domain of child development. Whatever the theory, it is a milestone for all children.

Early cognitive development stage: understanding physics

Children below the age of four understand gravity—they know that an object falls down if dropped. But when presented with an arrangement where balls cannot drop directly down but are diverted sideways, they often get it wrong. As with other tasks, this one can be made easier so that children are more likely to get the answer right. In this, case, how the tubes and buckets are matched up color-wise will influence how children predict the ball will fall.


The development of identity in early childhood

Child development milestones: gender identity

Gender identity is a key stage of development between the ages of two and five. It has begun already at two, with girls and boys using more same-gender-type words, such as boy, girl, truck, dress. By the time they enter school, boys and girls generally have different toy preferences. Boys are more likely to engage in rough-and-tumble play, while girls show more verbal and nurturing behavior. Gender segregation – the selection of friends of the same gender – starts at two in girls and three in boys.
There are a number of ways that child development psychologists understand this stage of development.

The “social learning” understanding observes that children model their behavior by observing and imitating others. Then they experience differential reinforcement – rewards for behaving in particular ways. Two- to five-year-olds are influenced not just by their parents, but by siblings, peers, other adults and what they see on TV and other media. Girls with older sisters and boys with older brothers are more stereotyped in their behavior than if their older sibling is of the other gender.

The “constructivist” understanding – based on Piaget’s stages of development – proposes that children create a “gender schema”, a mental model that is used to process gender-related information. Information can be objects, such as “boy things” and “girl things”, and routines, such as what Daddy does and what Mommy does.

Early experiences in school have an important influence on gender identity. If teachers emphasise gender more or less, children are more or less stereotyped in their behaviors.

Culture evaluates how children do and do not conform to gender roles.  In many Western cultures it is OK for girls to want to engage in stereotypical boy behavior, but it is much less acceptable the other way round. These unwritten rules can regulate behavior with some force.

Child development milestones: ethnic identity

The development of ethnic identity is an important stage for two- to five-year-olds. The process by which parents communicate ethnicity-related messages to children has been termed “ethnic socialisation.”

Researchers have identified two types of socialisation. “Cultural socialisation” emphasises ethnic heritage and pride. “Preparation for bias” emphasises awareness of ethnic bias and how to cope with it. Children whose parents promote ethnic pride and provide a home rich in culture tend to have stronger cognitive abilities and problem-solving skills and fewer behavior problems.

Child development milestones: personal identity

By the age of four, children have developed the ability to recount their own personal experiences by themselves. This personal story has been termed their “autobiographical memory.” As they develop this ability, they are likely to get assistance from their parents. At bedtime, for example, a two-year-old may ask a parent to tell them the story of their day. The parent and child together construct the story, with the parent shaping the story, playing some things up, such as the child’s capabilities, and playing some things down, such as the child’s fears. Some parents may introduce moral lessons to the story. This stage of development is very much shaped by the interaction with parents.

Child development milestones - ethnic identity

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At the early childhood stage of development, the child does not develop a subjective sense of self, for example, “I am shy” or “I am smart”. This comes later in middle childhood. Rather, two- to five-year olds communicate their identity by means of more objective characteristics: “I live in a big house.” “I have blue eyes.” “I have a kitten.”

Children of this age also do not distinguish well between what they can do and what they aspire to do, leading to rather exaggerated notions of their abilities. A child might say “I know all my ABCs” or “I can swim the whole way across the pool” when in fact they can do nothing of the sort. The ability to distinguish between aspiration and ability comes at a later stage of development.

The development of morality

The development of morality represents one of the key child development milestones. Two- to five-year-olds, when presented with moral stories, tend to focus on the objective consequences of the action, rather than the nature of the person’s motivation. Piaget, who examined the development of a sense of right and wrong, called this “heteronomous morality.”

Piaget asked children to consider the following two stories. Luke is warned by his mother to stay away from the freshly baked cookies cooling on the kitchen counter. When she leaves the room, Luke snitches a cookie and, in his clumsy haste, knocks over a cup that falls to the floor and breaks. Meanwhile, Zack is helping his mother to set the dining room table for dinner. With hands full of napkins and silverware, he pushes open the door leading from the kitchen to the dining room. When the door swings open, it hits a tray on which are stacked a dozen cups, all of which fall to the floor and break.

At the preoperational stage of development, the four-year-old will declare that Zack is the naughtier child because the consequences of his action are more severe. Older children regard Luke as naughtier, because he was deliberately disobeying his mother. Piaget terms this later stage of development “autonomous morality.”

(These stories also illustrate gender identity formation. Mommy is cooking and laying the table.)

“Social domain theory” distinguishes between different types of right and wrong:

    • Moral rules are based on principles of justice and the welfare of others. These rules are about not harming others.
    • Social conventions coordinate social behavior. These rules are about how to behave and dress and who has authority over whom.
    • Personal rules. An example is how to thank an uncle for a birthday present, by phone or letter.

Three- and four-year-olds can distinguish between these types of rules, responding quite differently to violations of the different types. The borders between the rules are sometimes blurred. Swearing could be considered a moral rule or a social convention. Running around naked on a beach could be breaking a social convention or be a personal rule.

The development of self-regulation: controlling actions

Further development of the capacity to regulate one’s own thoughts, emotions and behaviors takes place during early childhood.
Developing “effortful control” – the ability to concentrate on a task and inhibit impulsive or distracting actions – is a key stage of development in early childhood.

The ability can be tested by giving children a task that requires self-control or concentration. One test involves putting a desirable toy in front of children and asking them not to touch it. Another test involves sorting toys into different boxes in ways that require careful thought.

child development milestones - self-regulation

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Another measure is observation by parents and/or teachers: can the child wait before entering new activities when asked, can the child quit working on a project when asked, does the child concentrate when drawing?

Higher capacity for effortful control varies among children and predicts better academic performance and better social adjustment, such as stronger friendships and less aggression.

The two tests above are different in nature. The first – resisting the toy – is more emotional than the task of sorting toys, and it has been termed a “hot task”. Children good at hot tasks have been found to be better at working cooperatively with other children and less aggressive with their peers.

Some cultures, such as those influenced by Confucianism, emphasise self-control, and children in these cultures show greater ability in this area. Socioeconomic circumstances also influence this stage of development. Children from poorer backgrounds tend to show less self-control, though preschool progams can teach these skills successfully.

Play is an important part of this stage of development: playing a particular role in a game requires regulating thoughts and behaviors according to the imaginary situation. When the link has been tested, three- and four-year-olds who engage more in socio-dramatic play showed higher levels of self-regulation a few months later, even though there was no correlation between these variables at the start. These children were more attentive to post-activity clean-up and more attentive when gathered in a circle to listen to their teachers.

The development of self-regulation: socioemotional competence

At this stage of development, two- to five-year olds develop the ability to keep their emotions under control. They may avoid or reduce their exposure to an adverse experience by closing their eyes, turning away or blocking their ears. They may distract themselves with pleasurable activities. They may use their budding language and cognitive abilities to reinterpret events in a more palatable way (“I didn’t want to play with her anyway, she’s mean”), to reassure themselves (“Mommy said she’ll be right back”), and to encourage themselves (“I’m a big girl; big girls can do this”).

During this stage of development, children learn the difference between experiencing an emotion and expressing it. They can see when someone might be concealing an emotion. This ability develops in widely different ways from culture to culture. Children in cultures that more highly value social hierarchy and group harmony show earlier abilities to control their emotions than do children in cultures that emphasise autonomy and individual needs and desires.

The development of empathy and sympathy

Empathy and sympathy are defined as “prosocial behaviors” – voluntary actions to benefit others.

Empathy matures through early childhood, enabling a child to respond more sensitively to another’s distress. Their increased language ability expands the scope for them to empathize with people who are expressing their feelings verbally.

This developing understanding of others’ perspectives can work the other way, of course. A child may understand perfectly well why another child is in distress and may feel glad as a result!

Researchers have distinguished two reactions to the distress of another. Sympathy involves feelings of sorrow or concern for another person. This has been termed “other-oriented concern”. Personal distress, by contrast, is a self-focused reaction. Sympathy is more likely to lead to prosocial behavior. The capacity for self-regulation of emotion is key to the ability to respond with sympathy rather than just personal distress. Similarly, children with a greater capacity to focus their attention have a greater capacity for sympathy.


Lightfoot C, Cole M & Cole SR (2018), The Development of Children, Eighth Edition

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