HKU studies link between babies' learning abilities and future development
HKU researchers are testing babies to see how human perceptual and cognitive abilities develop. But getting them to co-operate can be a challenge, writes Jeanette Wang
Inside a laboratory at University of Hong Kong's psychology department, an infant sits in front of a computer screen and is shown an animated sequence: a smiley face accompanied by laughter, the smiley face again with the same laughter, and finally a sad face accompanied by crying. After all three faces appear in a row, the screen goes blank and the sequence is repeated.
The screen has a special built-in eye motion tracker to follow the viewer's gaze. Through tests infants, the researchers have found that typically after the sequence is repeated nine times, an infant's attention is cut by half.
"This means the infant has learned the sequence and is bored," says researcher and assistant professor Tseng Chia-huei, an expert in the fields of perceptual learning and visual attention.
"We then show a different sequence - maybe a smiley face, a sad face, then a smiley face - and see if the infant's looking time is restored."
But some infants continue to be amused by the old sequence beyond nine times. Tseng says this indicates the infant is slower in grasping the pattern.
Testing for such rule learning ability in infants is just one of the many studies being done at HKU's Baby Scientist Programme. Started in 2010, it has since recruited more than 600 Hong Kong families with babies aged up to 12 months to help researchers understand how human perceptual and cognitive abilities develop and mature.
"We started to study infants because at first we didn't believe that they could learn at such a young age," says Tseng, who has a PhD in psychology from University of California, Irvine, and has spent most of her career studying perception, attention and learning in adults.
"But so far I am convinced that infants have more cognitive learning ability than previously thought," she says.
Through the studies, the researchers are also beginning to understand the correlation between an infant's learning ability and his or her future development.
With the initial group of study participants now toddlers, some have returned for follow-up tests at HKU's speech and hearing sciences department.
"At follow-up tests at age two, we found an almost significant correlation: infants who couldn't learn the simple rule showed slower development," says Tseng, though she notes that the study size was only about 20, and more tests are needed to verify the result.
Such studies are valuable in the goal of identifying autistic children early on. For example, another study involving three-month-old babies analyses their face recognition ability. Most people are first drawn to the eye and mouth regions, but autistic kids usually aren't, Tseng says.
"What makes a person autistic is still unknown. Is it genetics or learning? More importantly, can you train them? If some kind of preference already exists in babies, then probably interventions can start earlier," says Tseng.
Recruitment of participants had not been difficult, Tseng says. But researchers are always in need of more infants, because the data success rate of the studies hovers around 50 per cent. That's low compared to a typical 99 per cent success rate with studies involving adults.
Babies have fleeting attention spans and variable moods, so getting them to co-operate can be a challenge. Each test usually involves 20 infants - meaning that 30 have to be recruited - and it takes each participant about 30 minutes.
"It's harder than doing an animal study because, with rats or monkeys, you can just give them a treat to co-operate. But that does not work with infants," says Tseng.
"That is why these studies are so valuable. No matter how much an animal study shows, they're not human," she says.
Tseng's lab consists of about a dozen researchers, including one full-time research assistant. The rest are HKU graduate and undergraduate students. The team needs not only to be able to run experiments, but also know how to handle children. For a student to be part of the team, he or she needs about 100 hours of training, Tseng says.
Participants get a HK$120 travel subsidy, and the infant gets a toy. Parents also receive a free test report. If the child participates a second time, a certificate of participation is given. Tseng says parents appreciate the certificate as it could help them when applying for places in preschools.
Mandy Chang Meng-yi signed her 20-month-old daughter Stephanie Huang up for the programme after learning about it on HKU's website. She found the results useful in understanding how her daughter, who was aged 10 months during the tests, was developing.
"As a new parent, you worry if your child's development is normal at a given stage. When she can't speak, you don't know if she really understands you; you can only guess," says Chang. "The study results motivated me to interact more with her and in the right ways."
Newborns are born largely blind, with dark, blurry, colourless and two-dimensional vision, Tseng says. While in the womb, there is no chance to develop vision. But they respond to auditory cues, which is why the best way to connect with newborns is to talk to them.
At two months, they start to see a bit of colour - mainly red and green. By six months, they can see in full colour, although images remain quite blurry. By one year, Tseng says, they can see almost as well as adults.
Up to four months of age, it's best to place things within 20cm to 25cm of a newborn's face as this is the limit of his or her visual focus. After three months, the baby should begin to be able to track objects and develop hand-eye co-ordination to reach for objects. Tseng recommends alternating feeding on the left and right sides, so that both the baby's eyes get the same developmental stimulation.
Between five and eight months, the baby's hand-eye co-ordination continues to develop and it starts to gain depth and colour perception. The baby also has the ability to recognise emotion in a voice. "Give them a lot of time to play, and explore on the ground; provide blocks they can grasp in their hands," Tseng advises.
Between nine and 12 months, hand-eye co-ordination is refined and the infant is better at judging distance and will experiment by throwing things. "They're not trying to test your limits; that's how they learn the world," Tseng explains.
Because the baby is able to see better, its memory starts developing. Tseng recommends playing hide and seek with toys, and naming objects while talking. This will help with visual memory development.
Are there any differences between baby boys and girls? Looking ahead, that's what HKU researchers hope to study in detail - how much of gender development is genetic and how much is social? Why do men and women, for example, tend to favour different professions?
Tseng's colleague, Dr Ivy Wong, found that differences show as early as three years old, with boys demonstrating better mental rotation ability, which is very important for architecture and engineering.
But Tseng notes that one possibility for the difference could stem from inherent bias in the person interacting with the baby boy or girl.
"If this is true, then we may need to change the way we interact with baby girls to empower them," says Tseng. "If gender development is not genetic, then there's a way to close the gap. The question is, do we provide the same kind of environment so that both boys and girls have the same ground to make their own choices?"