Science in the City: The Hamilton Spectator's Steve Buist interviews Terri Lewis

Terri Lewis

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Mark Loeb

Christine Wilson

Sarah Dickson

Barna Szabados

Arya Sharma

Miroslav Lovric

Terri Lewis

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Terri Lewis

The following article is reprinted courtesy of the Hamilton Spectator, McMaster University’s partner in the Science in the City Lecture Series.

Babies see at birth, prefer mom's face
McMaster professor to explain study of newborns that shows brain already hard-wired for recognition
Steve Buist
The Hamilton Spectator

It has been tempting for scientists to come to the conclusion that newborn babies are blind templates incapable of seeing the new world that surrounds them.

But a McMaster University psychology professor has helped show that newborns can not only see in the first hour after birth, they can also recognize basic shapes that resemble human faces.

Dr. Terri Lewis will discuss her fascinating research tomorrow night in The Spectator's auditorium in a lecture entitled First Sight: What Babies See.

It's part of the Science in the City lecture series, sponsored jointly by McMaster and The Spectator.

"A lot of people used to think babies were born blind," said Lewis.

"The problem turned out to be not with the babies but the way the questions were being asked."

Using electrodes, scientists can measure the electrical activity that's taking place in the area of the brain where visual signals are processed.

One of Lewis' most interesting projects was to analyze what babies could see in the first hour after childbirth.

She had a roster of pregnant mothers who agreed to notify her when labour was starting so that Lewis could test the newborns' vision immediately after childbirth.

"Of course, not a single mom remembered to call," laughed Lewis. "Luckily, there were people at Mac who remembered that these were mothers who had signed up.

"It was always in the middle of the night, so I had to throw on some clothes and run over," she added with another laugh.

In one case, she was even able to collect measurements from a baby seven minutes after childbirth.

The babies were shown a pair of giant cue cards, each with a different shape.

On one card was a lightbulb shape with three blobs in the middle -- two above that resembled eyes, and one below that represented a mouth.

On the other card was the same lightbulb shape, but the blobs were inverted -- one on top, two on the bottom.

"Right from birth, the babies preferred the one that looked like a face," said Lewis, adding that by three days of age, babies will already prefer the face of their mother to a stranger's face.

It suggests that the ability to recognize a face as an important feature is something that's already built in to the hard wiring of the brain.

Researchers have developed tests that can measure the visual sharpness of babies.

For example, in one test, brain activity is measured when a flashing checkerboard pattern appears in front of the baby's eyes.

The size of the checks can then be reduced so that brain activity can be compared to what happens when a blank gray background is shown to the baby.

The baby's visual sharpness can be measured by the size of the checks that can be perceived.

By testing large groups of infants at various ages, scientists can establish a range for what can be considered normal vision.

Even in the first days after childbirth, babies can see patterns that are about four times the size of the big 'E' on top of a standard eye chart.

By the age of six months, that will have improved by a factor of eight.

By about age five, children will have reached the visual levels of an adult.

"It used to be said that the world was a booming, buzzing mass of confusion," said Lewis, "and that babies weren't able to make sense of that confusion.

"It turns out the visual system is very good at sorting out that confusion," Lewis added.

Tomorrow night's lecture is free of charge and open to the public.

To register for a seat, call 905-525-9140, ext. 24934, or send an e-mail to sciencecity@mcmaster.ca.

Doors open at 6:30 p.m. and the talk begins at 7 p.m.

sbuist@thespec.com 905-526-3226