The Importance of the First 3 Years for Brain Development

Importance of the erarly years for brain development

There is a common belief that the first 3 years of childhood are key to the whole future life of that child, into adulthood and beyond. ‘The Myth of the First Three Years’ by John Brewer assesses the science behind the public perception. Whilst the book was published in 2002, a lot of the science within the book remains unchanged now as the human brain is so difficult to study. I found the book fascinating on looking into the science behind the views of the early years for development. In this blog post I summarise many of Brewer’s views, as well as consider attachment and gentle parenting implications. I also look to see if there’s been any updated science found on brain development in the early years.

One of my personal mum guilt’s was an awareness that the first 3 years of life are key to your child’s future successes, interests, brain function, to name a few. It is usually stated as the objectives of Mum and baby classes such as baby massage, or by health visitors recommending skin-to-skin contact, and also in some books that I’ve read in passing. I felt internally that I had not given my children the right wide ranging experiences. Also being relatively isolated with little support network I worried even the adult conversation was lacking. When I then had twins, and could barely even move from the sofa or bed because all 3 of my children were breastfeeding a lot, I felt even more guilt.

I’m aware that we spend time justifying our existence (see my previous blog post about the fear of death here), so am definitely biased in what I choose to read, write or relate to. I chose to read this because its title felt like it could alleviate my Mum guilt and it was possibly going to justify my children’s first 3 years as being better than I’d feared.

Some of the Theories About The Critical Early Years

There have been several theories about the importance brain development in the early years, resulting in public policies being amended for early years practice. However, there was little neuroscience findings to support the policies or opinions. The rationale of the changes to early years education and parenting recommendations was based on 3 themes.

Theory 1: Critical Periods

Firstly, adults who undergo surgery for cataracts are able to have their vision restored. In comparison, the surgery on children born with cataracts who were operated on at age 5, remained blind. They likened this to the importance of early brain development. One scientist inferred from the cataracts study that there are “early periods of development, windows of opportunity or critical periods… during which time experience is essential for brain wiring”.  There was a campaign launched in the White House which then fed into local government policies urging that the first 3 years will last forever and directly impact the future adults they become. The experiences a child has before the age of 3 was argued to determine whether they grew up to become toxic or non-toxic.

Theory 2: Increasing Nerve Cells

Secondly, there was a belief that there is a short early period where nerve cells connect into functioning circuits. It is the brain’s critical period for development. After this time, they believed, the brain could not form new synapses. They also argued that during these early years, the greatest help for brain development was stimulation and enriched environments.

Theory 3: Preventing Brains Cells from Dying

The third recommendation was similar to the first except rather than the formation of new synapses, it believed that lack of stimulation and enriched living would cause the synapses to die. They recommended that parents need to not just expose their children to certain key activities – but to everything. Loving, reading, cuddling, talking, as well as exploring.

Each of these theories can leave parents worried that failing to do a huge range of experiences will harm your child forever.

Why These Studies Are Questionable

Validating the above viewpoints with science finds a different story.

1. Monkeys who were highly stimulated were no different to those who were normally stimulated. It was concluded that genes determine the synapse formations, not environmental overstimulation influences. From another study on monkeys, it was found that genetics seemed to dictate the peak synapse quantity, and at that point is when the associated skills or behaviours appeared. Some studies on human babies also found that children given a task 10 times compared to children given the task the first time by the age of 1 year scored no differently. This showed that memory develops at approximately the same rate regardless of previous exposure to the activity.

2. The reports on brain development focusing on the number of synpases formed assume a link between the number of synapses and intelligence. There has been no study to see if there was a valid link. A big question mark arises when studying the number of synapses over the human lifespan. At birth and early adulthood, the synapse densities are comparable, yet we can all vouch that an adult is typically more intelligent and able than a newborn baby.

3. It also assumed that loss of synapses is detrimental to brain development, but loss of synapses is actually a natural and beneficial process to maturation. The “use them or lose them” saying implies you have control over this natural process.

Relating the Findings to Happiness

As I was reading the theories behind the importance of the first 3 years in childhood development, I did notice that all of the theories were focusing on the aim of increased intelligence. Some of the theories even justified their recommendations to reduce crime and toxic behaviours in adulthood. This implies that intelligence has something to do with this.

My main aim is that I want my children to be the happiest they can be (see my previous blog post about gentle parenting goals). Part of that may involve their perception of intelligence, but the brain theories did not touch on the importance of the early years for future happiness. Perhaps intelligence can help a child grow to feeling proud, accomplished and happy. However, it does not acknowledge that the feelings of happines come from within, from feeling valued and being free to be yourself around others, to bring out the best in yourself as well as others… I always say, and some people seem to take offense, but my aim is not for my children to be rocket scientists, unless that’s something they wish to do. If they do, they’ll be so interested to pursue that career that inevitably it would happen, even if it happened over a longer period than a comparably more intelligent child.

Implications for Gentle Parenting

John Brewer’s book does actually refer to studies around the attachment of a mother or father to their child being unaffected by childcare settings. The attachments were also unaffacted by whether the child remains at home or goes to childcare, even from an early age. The most important aspect affecting the parent – child attachment, is the mother or father themselves.

You would assume that if a child has an insecure attachment that they would always be that way after the 3 year critical period. Same as if the child is securely attached to the mother. Research mentioned in Brewer’s book also finds that the attachment relationship can change if the circumstances and relationships change, for better or worse. Attachment is not very stable, therefore, and parents aiming for strongly attached children need to maintain the attachments and connections to remain securely attached. They have been unable to predict a child’s future behaviour based on critical year attachments, unless that class of attachment remains the same over the subequent years. Therefore early experiences do matter, but so do all the experiences after the early years too!

Genes vs Environmental Experiences

Take the pressure off yourself and let go of any Mum guilt linked to a pressure to provide experiences, talk, read, exercise, teach them complex mathematical formula… Our survival as a species may have a critical window for brain development in certain key skills. Howerver, Brewer’s scientific evidence is that those essential skills are so likely to occur that the development will inevitably follow under normal circumstances, even across different cultural norms. It is only where a baby is in an extremely deprived environment, without any stimulation, that the critical window for developing those skills may be missed.

On that point of normal experiences of life helping to develop the natural genetics, I have first hand experience of same aged children developing at different rates inspite of being exposed to similar environments. Twins! My sample size study of one is not enough to draw conclusions, but it does verify to me personally that genes has a huge role to play in early years development. My eldest daughter started talking at around the age of 2, but before then babbled a lot and made funny sounds, had a sense of humour, naturally expressed her emotions through the most incredible facial experssions. She was a late talker compared to some, but her empathy was far superior to even many adults I’ve met before. One of the twins was unbelievably like her – slower to talk, but even babbled the exact same unusual sounds. He showed great levels of empathy and kindness very early on too. The other twin was very different to both of them. She said words very quickly, copied everything anyone said around her, although her empathetic side was rather lacking until shortly before her 2nd birthday. Interestingly, I feel this twin developed language at a similar rate to her paternal cousin. Perhaps my eldest and one twin had Mummy’s genes dictating their empathy and communication skills, whereas the other twin had Daddy’s and their cousin’s genes.

Up-to-date Science

Wow. I see what Brewer means that people are assuming popular belief to be fact, without drilling down to the science. Even more recent books or journal articles since 2002 still refer to supposed science about the first 2-3 years of brain development as if it is fact, when it is still in the early stages of research. From Brewer’s exceptionally written book, he urges us to drill down further than summarised findings, and to consider not assuming one study, on eyes for example, will equal the same result for all brain functions.

There are, however, books published more recently discussing new research in neuroscience. ‘The Neurobiology of Brain and Behavioural Development’, by Gibb and Kolb, was published in 2018, which goes into significant detail about the recent environmental factors which have been studied. Some of these environmental factors are:

  • The differences between newborns of a mother who smoked during pregnancy on various brain sections, compared to a non-smoker.
  • This book supports the same research debated in Brewer’s book on deprived animals or people and the effect on the brain. That is, if not surgically treated within a short timeframe, a human baby born blind will not be able to develop their site. This is an extreme example of deprivation which most babies will not experience.
  • Several studies on bilingual people found differences in abilities in cognitive tests as well as language abilities. Their brains also have differences to people only knowing their native language. They also seem better protected from cognitive decline with age.
  • Music training results in differences in the brain too. Musicians had improved reading, vocabulary, maths, working memory and spatial skills. Similar to bilinguals, musicians had improved odds for age-related brain deterioration such as a lower incidence of dementia.
  • Children exposed to early stress, prenatally as well as after birth, have shown different structures to the brain. Further, there are links to increased mental illnesses as well as impaired learning and memory.
  • Drugs and alcohol result in several brain and behavioural differences in the developing brain. The effects of exposure during pregnancy seem to reduce with time, but the brains were still differences found in late adolesence.
  • The relationship effects of a child to their parents, both positive and bad experiences, have also been found to contribute to the brain’s development too.
  • There may also be an effect of the number and opportunities to play with peers. No human study has been done on play yet but it has on animals.
  • Breastfeeding vs formula feeding studies have found that teenagers who were breastfed had different brain volumes, even more so in males.
  • Diet may play a role in affecting the brain’s development too, although no specific study has been done on humans for this yet. However, rats fed with supplements had children that had different brains than those not supplemented.
  • Children raised in poverty has found different brains on MRI scans, with the tests completed on newborn babies to 3 year old toddlers.

Many of the above environmental studies referenced are similar in nature to those debated by Brewer. Many of the science does not seem to have focused on activities to do with babies, but looing at things that have had recommendations over for a long time, e.g. no smoking, drinking or drugs during pregnancy. Other studies were mostly in animals rather than humans. Other things cannot always be controlled by individual parents, such as the children being raised in poverty findings.


Brewer felt that the science for normal brain development indicated that it will happen naturally and mostly due to genes in the early years, and only in later years do environmental influences have a play. He did say, unless the environment was so extreme i.e. no activities, then it could cause brain and / or development problems. Rather than being restrained by the first 3 years of experiences, our brains allow us to learn for the whole of our lives. However there are some critical periods of development throughout life, such as the studies found on eyesite in the early years. The subsequent studies done are still mainly on animals or extreme environments so do not necessarily offer much help for the majority of parents. However, there seemed to be a clear benefit to learning a second language or music early on in life.

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