Rebecca looks bizarre with brain-imaging gizmos attached to her little bald head—like a baby who has crept into Dr. Frankenstein’s lab. A white terry-cloth headband holds two plastic squares against either side of her skull. Each contains a set of black rods with a welter of wires. Rebecca seems oblivious to the headgear as she turns her head from side to side with a wet, toothless grin. She isn’t yet five months old, but according to Laura-Ann Petitto, a cognitive neuroscientist at Dartmouth College, she is already using the parts of her brain involved in language. And the contraption on her head is designed to let Petitto watch her do it.
Photograph by Dirk Anschütz
At Dartmouth College, laser light is beamed into a baby's head. Researchers analyze reflections from the laser for signs of brain activity during babbling.
Known as near-infrared spectroscopy, this technology is designed to show which part of the brain governs a given behavior by measuring where the brain uses the most oxygen. Petitto is learning how to use the device, and in time she hopes to zero in on an area just above the left ear that may play a prominent role in language acquisition. “Language is the looming contributor to this thing we call consciousness, which is at the heart of reason, emotion—the individual,” she says. “Think about what we’re doing right now. I’m sending sound waves through the air. I’m not even touching you. Yet you have explosions of meaning in your head. By what mechanism does our species accomplish this truly astounding feat?”
