by Teresa J. Mitchell
You come around a corner in the berry patch and see a couple bear cubs.
You might think, "Ah, so cute and fuzzy; I must hug them."
"Uh-oh! Where's their momma," should be your first thought after getting to a safe distance.
Non-human female mammals have been known to show high levels of aggression when defending their young. You don't want to mess with a momma bear.
It turns out you might not want to mess with a nursing mom, either.
Women who breastfeed are far more likely to demonstrate a "mama bear" effect. They're more likely to aggressively protecting their infants and themselves compared to women who bottle-feed their babies or non-mothers, according to a study in "Psychological Science."
Nursing Mothers Defend Babies with a Vengeance
"Breastfeeding has many benefits for a baby's health and immunity, but it seems to also have a little-known benefit for the mother," said Jennifer Hahn-Holbrook, a postdoctoral fellow in the UCLA Department of Psychology and the study's lead author. "It may be providing mothers with a buffer against the many stressors new moms face while at the same time, giving mothers an extra burst of courage if they need to defend themselves or their child."
Not only were the breastfeeding moms more aggressive, they had lower blood pressure. The authors add that breastfeeding may provide moms with a buffer against the stress that new moms face while at the same time, giving them an extra boost of courage if they need to defend themselves or their child.
"Breastfeeding mothers aren't going to go out and get into bar fights, but if someone is threatening them or their infant, our research suggests they may be more likely to defend themselves in an aggressive manner," Hahn-Holbrook said.
About the "Psychological Science" Study
The researchers recruited three groups of women. 18 were nursing mothers, 17 formula fed their babies and 20 women weren't mothers.
Each woman was asked to compete in a video game tournament, a series of computerized time-reaction tasks against a research assistant posing as an overtly rude study participant.
The winner of each round got to press a button and deliver a loud and lengthy "sound blast" to the loser. Nursing moms gave the rude assistant blasts that were twice as loud and long as the other women in the study. This was true before and after nursing their babies.
While dishing out the longer and louder punitive sounds, lactation mediated the body's response to stress. Researchers measured stress levels via systolic blood pressure. The breastfeeding mom was about 10 points lower than moms who were feeding formula to their babies and 12 points lower than non-mothers.
Previous research in non-humans shows that lactation heightened defensive aggression by down-regulating the body's response to fear, a phenomenon that benefits the survival of both mothers and their offspring. The researchers say that the lower blood pressure is an indication that the same mechanism is likely at work in humans, too.
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- Hahn-Holbrook, J et all. (October 2011). "Breast Feeding Increases Aggression by Reducing Stress." Psychological Science October 2011 vol. 22 no. 10 1288-1295.