Cognitive development refers to the evolution of the ability to think and understand. In a child, it starts with basic processes such as perceiving objects and events in the environment, and understanding and processing language.
Gradually, it reaches more advanced levels such as the formation of thought processes, which includes intelligence, language skills, reasoning power, decision-making and problem-solving skills, conceptualising and planning, and memory.
It is important for parents to know about the normal course of cognitive development in children for two reasons:
- It helps them closely monitor the development of their children and plan activities to help them develop various skills.
- It helps them understand early on whether their children are suffering from developmental delay and seek early medical or therapeutic intervention. This makes it much easier to deal with issues than when the diagnosis is delayed.
Let’s look at some key cognitive milestones that children are expected to achieve at various stages of their growth during the first six years.
0 to 3 months
Newborns become capable of surveying their surroundings soon after birth. Most infants possess the ability to concentrate on moving bodies and can follow them with their eyes. During the first three months of infancy, babies can
• recognise faces
• imitate the facial expressions of others such as smiling and frowning
• respond to familiar sounds
• differentiate between the volume and pitch of sounds
• distinguish between various colours based on hues and brightness
• associate events with certain sights
3 to 6 months
During this time, babies start developing the power of perception. At this stage, they
• know who their parents are
• can imitate sounds
• can develop stranger anxiety (fear of strangers)
• can differentiate between animate and inanimate objects
• can judge distance based on the size of objects
• can drop and pick up objects
6 to 9 months
By this age, most babies can
• respond when called by their names
• imitate gestures and actions
• start fiddling with objects,
• understand the meaning of simple words like ‘no’
• recollect the existence of an object even they can’t see it
Some babies may also try to see how their parents react to their actions, such as throwing food on the floor. They are capable of memorising reactions and may repeat their actions to see whether their parents react in the same way every time they do it.
9 to 12 months
As babies approach their first birthday, they start
• speaking short words like ‘mama’ and ‘papa’
• mimicking sounds of animals
• associating objects with their respective names like ‘toys’, ‘blankets’, etc.
• displaying symptoms of separation anxiety when away from parents
12 to 18 months
Once children are more than a year old, the speed of their cognitive development increases, and they
• can process and understand around 10–50 words
• can identify parts of the human body
• develop a sense of ownership by associating the word ‘my’ with a select group of people or objects
• can follow instructions involving two different tasks like picking up toys and placing them in a box.
18 months to 3 years
According to Piaget's theory of cognitive development, between the ages of 18 months and 3 years, children remain in the ‘sensorimotor’ stage. Children of this age group
• have a heightened sense of permanence of objects and people
• can follow the displacement of objects visually
• can make use of instruments and tools
• can understand basic emotions such as trust and fear
• can process and understand 100–150 words at a time
• add around ten new words to their vocabulary every day
They also begin to seek more freedom, which can be challenging for their parents at times, especially when it comes to matters of safety. They start understanding the concept of discipline and the difference between appropriate and inappropriate behaviour. They learn the meaning of expressions like ‘please’ and ‘thank you’.
3 to 6 years
Between the ages of 3 and 6, children have a self-centred view of the world around them. They need to be taught how to learn and memorise. This is also the age when they enter the preschool stage and develop social interaction skills such as playing and cooperating with other children of their own age.
It is normal for preschoolers to test the limits of their cognitive abilities, and they may start exhibiting negative behaviours such as talking back to adults, lying and bullying. Other signs of cognitive development in children of this age group are:
• an increased attention span
• ability to read
• developing structured routines, such as doing household chores
It is important for parents to be aware of cognitive milestones to spot any developmental delay or deviation in their children. This will enable them to seek assistance from experts early on and provide their child with the help necessary to catch up with his peers.
When to contact the doctor:
Parents should consult a developmental paediatrician if their baby
• does not exhibit social smile after he is 2 months old
• does not respond to sound of a rattle or his name being called by 5–6 months of age
• does not have stranger anxiety by the time he is 7–8 months old
• does not learn to identify body parts by the time he is 15 months old
• does not start talking even after he is 2 years old
• has problems understanding simple directions
• seems confused when asked to perform simple actions even at 3 years of age
The author is a Newborn and Child Specialist, Consultant Pediatrician at Nanavati Super Speciality Hospital.
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