Humans are the dominant species on Earth because of our superior intelligence, compared to the other living beings on this planet.
Our intelligence evolved, not so much due to the size of our brain, but because of the ratio of our brain’s weight to the weight of our body.
Of all creatures, humans have the largest brain to body weight ratio, meaning that we have relatively heavy brains for our body size.
In addition, the cerebral cortex in humans is the largest, relative to body weight, among all the mammals, which are the only living beings to have a cerebral cortex.
This area is crucial to our intelligence as part of the cerebrum, which is responsible for our thinking, judgement, memory and communication skills, among others.
According to consultant paediatric neurologist Prof Dr Wong Chee Piau, there are three major stages in the development of a normal brain.
“When we talk about brain development, we look at three major events.
“First, obviously, you have to form the brain, which is called neurogenesis.
“Once you have formed the brain, then you have to connect the brain, which is called synaptogenesis.
“Then the third thing is to speed up the processing, which is called myelination,” he explains.
Forming our brain
For such an essential organ, our brain actually reaches its full development when we are about 25 years of age.
After that, it plateaus, and eventually starts to decline as we hit our senior years.
Says Prof Wong: “In the womb, neurogenesis, or the formation of the brain’s structures, occurs as early as six weeks into the pregnancy.
“Very simply put, it starts with a few neural cells, then it forms a sheet, then it forms a tube, then it forms a ball, then the ball eventually divides into two halves (the left and right hemispheres), and towards the end, the two halves become wavy (with grooves and bumps) as per the familiar appearance of the brain.
“And all this forms before we are born.”
Although the brain develops until young adulthood, the most active period of development starts from conception until about two years of age.
“That is probably the most intense period (of brain development) – some people call it the exuberant period,” he adds.
Prof Wong notes that we are actually born with more brain cells than what we end up with when the brain completes its development.
“It’s almost like saying when you build a house, you buy a lot of bricks; then, when you finish building the house, there are some bricks left over and those bricks get thrown away.”
This is because the next part of brain development – synaptogenesis – is crucial in making the brain work.
“There are a lot of brain cells. Some will connect, and those will remain because they become functional. Those that do not connect are not functional and will disappear,” he explains.
He adds that the latter process is known as synaptic pruning, which helps improve the brain’s connections, similar to how pruning a bonsai tree improves its growth and appearance.
The final part of brain development is to speed up the connections between our brain cells through myelination.
“Myelination is the maturing process of the brain connections,” says Prof Wong.
“In our brain cells, we have a cord called an axon, which is like the central metal cable in wiring. The myelin will form a sheath covering the axon – that is the process of myelination.”
He adds: “While we say that the covering of wiring is for protection, myelin is not only for protection, but it also serves the very important function of substantially speeding up the transmission of electrical impulses in our brain.”
This enables us to think and react quickly, and may influence our learning ability, as it speeds up the processing of information.
Nature and nurture
Now, the million-ringgit question, of course, is if there is any way to make yourself or your child more intelligent.
This is where both nature and nurture come into play.
Says Prof Wong: “You are born with a certain amount of ability and I think it’s quite difficult to go beyond what you have. Nature is such that it limits your maximum potential.”
For example, as we have the ability to learn how to walk, we can eventually learn how to run fast.
But no matter how fast we can run, we will never be able to run beyond a certain speed – say, for example, faster than the speed of sound (343 metres per second) – as it is not within our physical ability to do so.
Meanwhile, nurture helps to maximise a person’s potential and is the part that we can affect for our children and ourselves.
“The nurture part is obviously multi-factorial and very complex. For example, nutrition definitely plays a big part – if children don’t eat well, their brains won’t grow well.
“Putting them into an enriching environment where they learn the right things is important (i.e. stimulation).
“And giving them tender loving care – a caring environment – is also very important,” says Prof Wong.
He gives the example of a child brought up in an orphanage, who has the same potential (nature) and nutrition as one who lives in a stable, loving home.
The first child is less likely to achieve as much as the second one, due to a less enriching and loving environment.
“Even with maximum potential, there is a lack of nurturing to push them to the max, and that is quite important,” he says.
As for us adults, the bad news is that our number of brain cells is fixed, and will probably decrease as we age due to natural cell death.
However, don’t despair, the key to maximising what we do have is to ensure we continually stimulate and use our brains throughout our lives.
As Prof Wong says, “You have to use it or lose it.”
So, what can parents do to maximise their child’s potential?
It all starts even before conception.
According to Prof Wong, nutrition is very important for women who are ready to try for a baby.
Aside from eating a balanced diet, he advises mums-to-be to start taking folate, also called folic acid, supplements.
Parents are probably aware that folate is one of the required supplements – along with iron – that mothers have to take during their pregnancy.
This is because folate is known to help prevent neural tube defects that can result in conditions like spinal bifida and anencephaly (where a large part of the brain and skull is absent).
As neural tube defects are most likely to form during the first few weeks of pregnancy when most women might not even know they are pregnant, it is ideal to start taking folate supplements as soon as you are ready to try conceiving.
“The second thing is stress – maternal stress does affect the formation of the fetus,” he says.
He notes that extreme physical stress like running a marathon already stretches a person’s physical limits, what more if that person is carrying another person within her.
“So, I would say moderate physical activity is welcome, but extreme physical activity is not.”
As for mental stress. Prof Wong says that it can result in three things that may affect the baby’s development: lack of sleep or insomnia, hormonal changes and substance abuse, which is a problem on its own.
He notes that substances like alcohol, cannabis and heroin, when taken by mum during pregnancy can also adversely affect her baby.
“For example, if mum drinks a lot of alcohol, her baby will end up with fetal alcohol syndrome.
“This is bad news for the child’s brain – the child will have a lot of learning difficulties, a lot of behavioural problems, etc.”
He also notes that if mum-to-be is on any medications, particularly long-term ones, she should see her doctor to ensure that the medication will not adversely affect her future baby.
“For example, women with epilepsy who take sodium valproate might want to see if it is possible to either reduce their dose, or better still, change to another anti-epileptic drug, as sodium valproate affects the baby’s development, resulting in fetal valproate syndrome,” he explains.
For both parents-to-be, advancing age is also an important issue.
Says Prof Wong: “What happens is that our body constantly gets injured and we constantly repair ourselves. Same thing with our genetic material – it constantly gets damaged and repaired.
“When we are young, the repair efficiency is much better. As we grow older, we find that the gene repair is not as good and it can be faulty, and if you pass that faulty gene on to your baby, you might have a problem.”
An example of this is Down syndrome, which is associated with advancing maternal age.
“We know that advanced paternal age is also associated with subtle problems in the baby – not as clearly linked as Down syndrome is with maternal age, but we do know that certain syndromes are associated with advanced paternal age,” says Prof Wong.