Year after year, the greeting card and flower industries goad us to honor our mothers, and we Whyfilers are glad to comply. This year, we celebrate by exploring what we learned about mothers at the February, 2011, meeting of the American Association for the Advancement of Science — the AAAS.
It may sound obvious, but understanding mothering helps us understand our world!
Mothers make us better people (Duh?)
More than 50 years ago, when University of Wisconsin psychologist Harry Harlow separated infant monkeys from their mothers, they grew up anxious, jittery, emotional wrecks. It’s amazing to think somebody needed to prove the value of mother’s love, but during Harlow’s time, behaviorism — a psychology rooted in the study of rats — was ascendant.
Academic psychologists focused on stimulus and response, not on the intricacies of the heart.
Today, Harlow’s findings seem like simple common sense, but they made him a rock star to the public — and eventually to his academic colleagues.
Stephen Suomi, one of Harlow’s last graduate students, has continued this line of research at the National Institute of Child Health and Development, again using rhesus macaque monkeys to model human behavior.
Genes don’t equate with destiny.
Back in Harlow’s day, genes were seen as destiny. Now, scientists like Suomi are finding a more interesting and flexible interaction among genes, environment, behavior, hormones and brain structure.
Suomi says that like people, “Between 5 and 10 percent of macaques are unusually impulsive; they do stupid things that most monkeys would not try. They will confront a dominant monkey. Most monkeys know how to back off, but when these monkeys are in an aggressive encounter, somebody can get hurt.”
Similarly, by age 2, some children “are identified as highly aggressive and likely to stay highly aggressive as they grow up,” Suomi says. “At school, they cause classroom disruptions. By their teens, many can be found in prison or the morgue.” In both monkeys and people, “these features show up very early and are remarkably stable.”
Stay close, my baby
Psychologically and physically, the infant monkey is reliant on its mother. Infant macaques “are almost always in physical contact or within arm’s length of their mother,” says Suomi, “which forms a strong, enduring attachment bond that is the functional equivalent of the one that human infants form with a caregiver.”
After a couple of months, that bond is established and the infant starts to explore, using mother as a “secure base,” Suomi says. “If they lose access to her, any motivation to explore will disappear; they get unhappy.” As these developing monkeys spend hours playing with peers, “every behavior pattern for normal functioning is established.”
Harlow raised infant monkeys with inanimate replacements for the mother and saw a range of deranged behavior. These days, Suomi removes young monkeys from mother and raises them with other youngsters. These “peer-reared” monkeys (are you thinking Lord of the Flies?) — develop what Suomi calls “hyper attachments. They spend excessive amounts of time clinging to each other when they should be exploring their world.”
Under these circumstances, play never reaches the normal “intensity and complexity,” Suomi adds.
I’m afraid. Why aren’t you?
To understand why this is of more than theoretical interest, we need to meet serotonin, a key chemical for communication among neurons. Some variants of the serotonin genes are linked to high rates of suicide, depression and incarceration, and serotonin metabolism is affected by Prozac and other drugs.
In behavior, Suomi says, the peer-reared monkeys resemble the 5 to 10 percent of normal monkeys that are naturally fearful, anxious and aggressive. Both groups have a defective use of serotonin, but in the peer-reared monkeys, “this is not a product of genetics, it’s a product of social experience.”
Certain variants of the serotonin gene — and also certain experiences — are associated with increased desire for alcohol, Suomi says. When adolescent monkeys attend “the monkey version of a happy hour, some consume more than others, and the peer-reared ones consume considerably more.”
Early experience, in fact, affects the activity of one-fifth of monkey’s entire genome, Suomi says.
Suomi’s studies also show that drinking behavior is crucially dependent on upbringing: a good “childhood” can cancel out the effects of “negative” genes. “If the monkey has a good mother, it doesn’t make a damn bit of difference. It does not matter which alleles [variants] are present; you have normal serotonin metabolism. A good mother protects those who carry this allele, and it’s the same story in aggression, the same story with alcohol. With a good mother, you drink less.”1
Why does momma matter?
The role of genetics has been a highly controversial area in development. A century ago, genes were destiny: people were essentially robots acting out immutable genetic instructions.
Then the focus shifted to external factors, and autism, for example, was blamed on a “cold” mother. Within a few decades, the advances in analyzing the structure of genes returned genetic determinism to vogue, and researchers began to search, for example, for an autism gene.
That approach quickly faded, W. Thomas Boyce of the University of British Columbia told the AAAS, in favor of a more sophisticated “behavioral genetics” focused on gene-environment interactions.
Now, in recognition that chemicals that are modified by experience affect the activity of genes, that picture is being enlarged in a discipline called epigenetics. In this new view, genes affect our environment, and environment affects whether and how genes act.
“The old metaphor of the genome being a blueprint for constructing the developing brain is faulty in certain ways,” says Boyce. “It may be more accurate to say that we begin with a blueprint, and partly build the house, then the family moves in and the blueprint gets modified. There is a feedback that alters the expression of the blueprint, based on the experience of the individual living in the house.”
The long shadow of poverty
How does this play out in the real world? Unstable and unmarried families tend to be poor, and social class correlates with higher rates of asthma, disease and injuries, says Boyce. At birth, physicians routinely record measures like weight and gestational age as a rough gauge of health, but Boyce thinks they ought to add social factors to the mix.
In fact, a study2 that tracked health and education in 4,667 infants born in Winnipeg, Canada, for 19 years showed that the traditional biological measurements were less predictive than social factors related to health and education.
Since “half the world’s children grow up in poverty,” Boyce says it would make sense to look more closely at social risk factors, rather than focus on physical measures. Given that “15 to 20 percent of the overall population is responsible for over half of medical, psychiatric morbidity, and physician and health care use,” understanding social risk factors could be a key step to ameliorating poor health, he says.
The fragile family
As the American family has changed — some would say disintegrated — social scientists have shifted their focus from divorce, to the “fragile families” formed by unmarried couples. In some fragile families, the mother is single; in others she and the father are cohabiting.
“About 40 percent of American children are born into an unmarried family now,” says Jeanne Brooks-Gunn of Columbia University, a principal investigator on the Fragile Families and Child Wellbeing study.
The study is looking at the environments in which children are being raised, and which factors are most harmful to their health, welfare and education. “Some situations are stable, while others are not,” says Brooks-Gunn.
The Fragile Families study has followed about 5,000 children for nine years, with a focus on “stability and chaos, how they affect resources and investments in child well-being” Brooks-Gunn says. “Nobody will ever do this again; getting approval at 75 hospitals was a nightmare.”
Study personnel interviewed the mother within 24 hours of birth, and also a rather surprising 75 percent of the unwed fathers, Brooks-Gunn said. “Babies are darling, and everybody comes to the hospital to see them.”
The researchers then observed the children at home at ages 3, 5 and 9, to gather data on physical, social and psychological development, and they found the original optimism fading.
“At birth, everybody expects things will go well; 75 percent of the [unwed] mothers believe they will marry the father,” Brooks-Gunn says, “but by year five, the relationship with the biological dad has ended for two thirds of these mothers. There is a huge increase in new partners, and in having children with a new partner.”
As a rule, the fathers who spent time with their children were those who had not had a child with another woman, says Brooks-Gunn. “And when the mother has a new partner, the father is out of the picture.”
The Fragile Family study3 found that:
- At age 3, children in stable families (whether married, co-habiting or a single mother), had better vocabulary than children of married or cohabiting parents in an unstable relationship.
- Children’s cognitive scores improved when their unwed parents marry.
- Each additional change in family structure increases the odds of behavioral problems. With more family and residential transitions, the mother becomes more likely to report stress and hitting her children.
- Conflicts in the parental relationship intensify behavior problems in children, regardless of the stability of the family structure.
- Having a single mother raises the odds of obesity, asthma, hospitalization and accidents.
This is not to say that simply being unmarried is the direct cause of all problems, given the many other factors in play, as Brooks-Gunn and colleagues noted. “While children born to unwed parents are at higher risk of low birth weight … women who are not married at the time of the birth are also more likely to smoke cigarettes and use illicit drugs during pregnancy, and less likely to receive prenatal care in the first trimester of their pregnancy, all of which are associated with low birth weight.”
Many factors may explain how a parental relationship affects children, Brooks-Gunn indicated:
- Parental resources: How much time, money and education?
- Parenting quality: How do the parents interact with the child?
- Father involvement: How present is he?
- Parental relationship: Are the parents stable and loving? Do they interact well with the child?
- Parental mental health: How well are the parents, psychologically?
The Fragile Family studies “add to a large body of earlier work that suggested that children who live with single or cohabiting parents fare worse as adolescents and young adults in terms of their educational outcomes, risk of teen birth, and attachment to school and the labor market than do children who grow up in married-couple families,” Brooks-Gunn and colleagues concluded.
Overall, the findings are distressing, Brooks-Gunn told the American Association for the Advancement of Science in February. “Our findings are more negative than I would expect. There is a lot of instability, and that affects this incredible disparity in how children are doing. This has incredible consequences for society. Forty percent of all kids are born into a non-married household. We are talking about diverging destinies.”
– David J. Tenenbaum
- Adverse rearing experiences enhance responding to both aversive and rewarding stimuli in juvenile rhesus monkeys, Biological psychiatry [0006-3223] Nelson vol:66 iss:7 pg:702 -704. ↩
- Rethinking What Is Important: Biologic Versus Social Predictors of Childhood Health and Educational Outcomes, Jutte, Douglas et al, Epidemiology: Volume 21(3), May 2010, pp 314-323. ↩
- Fragile Families and Child Wellbeing, Jane Waldfogel, Terry-Ann Cragie and Jeanne Brooks-Gunn, Volume 20 Number 2 Fall 2010 ↩
- Love at Goon Park, Deborah Blum, Basic Books, 2002. ↩
- Fragile families and child well-being. ↩
- Fragile families. ↩
- National Center for Children and Families. ↩
- National marriage project. ↩
- The Future of Children. ↩
- The fragile famile effect. ↩
- Understanding fragile families. ↩
- History of mothers day. ↩
- The trouble with motherhood. ↩
- Changing face of motherhood. ↩
- National survey of family growth. ↩
Tags: aggression, alcohol alcoholism, children, epigenetics, Fragile Family Study, Harry Harlow, human development, Jeanne Brooks-Gunn, marriage, monkey, mother mothering, parent, psychology, serotonin, Stephen Suomi, University of Wisconsin Madison UW-Madison, W Thomas Boyce