Pushing back the frontiers of research into babies’ budding brains, a recent study in the journal Neurology points out that, at least for pre-term infants born before 30 weeks gestation, the rate of brain growth –rather than the brain’s sheer size – may be predictive of their future intelligence.
Of course, understanding the delicate underpinnings of the human intellect is no easy feat. To shed some light on the topic – and the recent preemie study – we spoke to URMC psychologist Heather Adams.
Scripts: What does this new research with preemies teach us about the last two months in the womb?
Adams: It underscores the dramatic brain changes already underway. Babies’ brains go through a big, important growth spurt in the last trimester.
S: What can pregnant women do to encourage their children’s brain growth while in-utero?
Adams: Well, I’m not a physician – so I can’t give recommendations to pregnant women – but prior research suggests that there are things that can happen to a fetus to either promote or interfere with its optimal brain growth. For instance, a study of Inuit mothers and babies showed that their diets, which are traditionally rich in poly-unsaturated fatty acids, had beneficial effects on the length of gestation (bringing a baby full term). Also, their DHA (fish oil) intake was related to their babies’ cognitive and motor development. (See another blog post on this “fishy” topic, here.) Other studies similarly have confirmed that the mother’s diet and overall health has bearings on fetal brain development.
Of course, risky habits like smoking, drinking alcohol, and using cocaine have been shown to negatively affect in-utero brain growth.
S: What can new parents do to promote their babies’ brain growth/intelligence after they’ve been born? (Are any of those “baby genius” products founded on real science?)
Adams: Researchers at the University of California, Riverside, have been studying the relationship between this “baby media” (including but not limited to videos such as Baby Einstein, Baby Mozart, etc.) and child development. Their work is still is process. One study published in 2010 in the Archives of Pediatrics & Adolescent Medicine found that there was no indication that watching these kinds of videos promoted language development – so we’ll have to see. What’s more, there have been many other studies suggesting that infant learning takes place through babies’ interactions with their parents/caregivers – being read to, playing games, having positive social relationships/attachments, etc. So, that might be more important.
S: Does this latest research imply that part of our brains – and our future intellectual destinies – are hardwired (in part, at least) before we’re even born?
Adams: Yes! We know that there are genetic influences on a child’s intelligence, on his or her ability to learn, and on educational outcome. One recent study even concluded that genetic differences among children attribute for about 50 percent to their school achievement.
Scientists continue to ask how the environment in turn interplays with these genetics to allow intelligence and aptitude to develop over time. What we do know is that, in studies where identical twins are separated at birth (not for the purpose of the research, of course!) and raised separately, their intelligence test (IQ) scores are still more similar to each other’s than to those of their adoptive siblings.
S: What do we know about pace of brain development and growth throughout childhood?
Adams: A newborn baby’s brain is about one-fourth of its final adult size; in terms of weight, it more than doubles in the first year of life. By the time a child reaches 3 years old, his brain is about 80 percent of its adult size; by 5 years of age, it reaches 90 percent. That’s a lot of important growth in a very short time.
In addition to physical changes in size and weight, the brain is undergoing critical organizational developments. Neuronal (brain cell) pathways become more efficient over time. We researchers refer to this in terms of two important processes: Myelination and pruning.
Myelination is the development of a fatty coating that covers “axons” – the long branches between nerve cells, reaching out and allowing them to communicate with one another. This coating, which improves axon “talking,” begins to grow around birth and develops rapidly in the first few years of life – perhaps even continuing through young adulthood. “Pruning,” on the other hand, is a way that the brain “trims itself back” to become more efficient. The overall number of neurons and the connections between them actually decreases from birth to adulthood – but this process strengthens the brain, and makes remaining connections much speedier.
Researchers are still busy working to develop a “brain atlas” to better understand and map the developing brain, but ultimately, development is believed to continue through the early to mid-twenties, generally maturing in a back-to-front pattern. The front of the brain — which serves skills such as impulse control, planning, abstract thinking, reasoning abilities, and self-monitoring — develops in a rudimentary fashion throughout childhood, but it’s not until the teen years and beyond that these functions really start to hum.
S: Can a parent’s actions really help a child become smarter? And can IQs change significantly over a lifetime?
Adams: Ah, this is a tough one! It’s certainly not as simple as saying “If a parent does X, a child will become smarter by Y additional points on a standard IQ test.” There is a rich and complex interplay between what you’re born with (your biological makeup – which includes, but is not limited to, the intelligence level of your parents), your environmental exposures are before and after birth, and your educational experiences.
In 2007, the National Institutes of Health’s MRI study group published a paper reporting that, on a battery of neuropsychological tests, the largest intellectual growth occurred by the time kids turned 10, and then leveled off after. So, even though the brain continues to develop anatomically during the teen and early adult years, and new learning continues to occur and skills are refined, the major developments in cognition probably occur before the teen years.