NEW ORLEANS — When babies fail to form trusting relationships with their mothers, psychologists have long offered a quick answer: Blame Mom.
A new view is taking hold. Some infants--especially fussy ones--put up a barrier that has nothing to do with their mothers' skills or compassion.
In short, the new wisdom holds: Blame Baby too.
"The mother is off the hook, at least in part," said Dr. Carroll E. Izard.
Delving into infants' emotions has become a rich field of research. Developmental psychologists are busy sorting out emotionally responsive infants from stoic ones, tracking down the source of emotional responses inside their young heads and even measuring which side of babies' faces break into the brightest grins and the deepest frowns.
Izard, a researcher at the University of Delaware, is challenging the traditional notion that mothers are entirely responsible for building secure relationships with their babies.
He has found that babies who respond strongly and negatively to noises and other stimulation--in short, the very fussy ones--are also most likely to develop poor bonds with their mothers.
"Previous research puts the onus on the mother," said Izard. "I'm saying this is a two-way street. Characteristics of the infant contribute as well."
His study, conducted on 81 infants, found that those who cried the most, who demanded the most attention and who put up the biggest fuss during mildly stressful situations during their first months of life also turned out to be the least secure at 13 months of age.
He and his colleagues found that they could use an electrocardiogram to predict which newborns would go on to have insecure bonds with their mothers. Those with the strongest vagal tone--a measure of the influence of the brain on the heart--later produced the highest insecurity scores on psychological tests.
In Izard's study, a quarter of the babies formed poor bonds with their mothers. Other research has shown that such children are more likely to have psychological problems when they reach school age, such as extreme shyness and difficulty playing with other youngsters.
The latest work suggests that the seeds for these social problems are sewn in a baby's genes at birth.
Izard outlined his findings recently at a meeting of the American Assn. for the Advancement of Science in New Orleans. Other researchers at the meeting described other ways of delving into the earliest emotions of childhood.
For instance, Dr. Tiffany Field of the University of Miami Medical School has tested babies' willingness to mimic grown-ups' facial expressions of happiness, anger, sadness and surprise. About 20%, it turns out, are great apers, bursting into wide grins and gaping surprise in response to adult cues. Another 20% stay stone-faced, while the rest fall somewhere in between.
"Expressivity is something that is individually different right from the start," she said.
Dr. Nathan A. Fox of the University of Maryland has found that different emotions are seated in different sides of babies' brains. He measured youngsters' brain waves on EEGs. Among other things, he found that when babies smiled at their mothers, the left side of their brains was usually more active, while the right side seemed to be busier when they cried in anger.
He believes that learning more about how the frontal lobes of babies' brains mature will provide important clues to understanding the development of differences in personality.