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Forget Mommy Brain and all its connotations of a spacey, ineffectual new mother. Researchers are zeroing in on another post-natal effect at the other end of the spectrum: Say hello to Mama Bear.

A new study has found that women who breastfeed are far more likely to aggressively protect their infants and themselves than women who formula-feed their babies or non-mothers, according to a release from UCLA, one of the research partners.

In the study, three groups of women – 18 nursing mothers, 17 women who were feeding formula to their babies and 20 non-mothers – played computerized games against a research assistant "posing as an overtly rude study participant." If they won a round, moms were allowed to press a button and deliver a loud and lengthy "sound blast" to the loser - the act of aggression.

Breastfeeding mothers' sound blasts were more than twice as loud and long as those administered by non-mothers and nearly twice as loud and long as those by formula-feeding mothers," according to the release. What's more, the breast-feeding moms who were more aggressive actually registered a lower blood pressure than the others.

"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," said Jennifer Hahn-Holbrook, a postdoctoral fellow in the UCLA Department of Psychology and the study's lead author, in the statement.

Now, before you start with the jokes, Ms. Hahn-Holbrook says there are limits to the aggression women might display.

"Breast-feeding 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," she said, adding that the effect has been documented in other mammals before, but not humans.

Amy Keyishian over at The Stir cautions moms not to let the study fuel the breastfeeding versus bottle debate.

"Because though I love the idea that these hormones make me into a scary super-mom, I don't want us to forget that the difference between a lactating mom and a regular-old mom is probably pretty small.

"Once we become moms (especially when sleep-deprived and weak with the tender-hearted pain of our expanding emotions), we all go a little ape when someone annoys us, especially when it involves a threat to our kids," she writes.

Moms out there, did you sense some kind of Mama Bear Effect when your kids were infants?

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