Why do people want to eat babies? Scientists explain.

Admit it: When presented with a baby, you've experienced a fleeting desire to eat it. Now science has an explanation.

If you're like most normal people, you've briefly considered eating a baby or two.

Not literally, of course. That would make us no better than hamsters or wolf spiders. But pretend baby-eating – that is, explaining to an infant that she is so cute that you just want to gobble her up, or, in extreme cases, gently grabbing a pudgy appendage and making Cookie-Monster eating sounds – is not unheard of among H. sapiens.   

Why is that, anyway? Why do babies always seem so metaphorically delicious, even when you're not particularly hungry? Using brain scanners and pajamas, an international team of scientists is closing in on a answer. 

Apparently it has something to do with the way babies smell. A paper published in the current issue of Frontiers in Psychology describes how researchers in Dresden, Germany, imaged the brains of two groups of 15 women while the women sampled the odors of other parents' newborns. One group was composed of women who had given birth within the past six weeks. The other group was made up of women who had never given birth. The scientists collected the smells from the pajamas of two-day old infants.

The smells were shown to elicit activation in the women's' brains' reward circuits. 

“This circuit makes us desire certain foods and causes addiction to tobacco and other drugs,” said University of Montreal researcher and study co-author Johannes Frasnelli, in a news release. “Not all odours trigger this reaction. Only those associated with reward, such as food or satisfying a desire, cause this activation.”

What's more, the mothers' reward circuits showed far more activation than those of the non-mothers; for moms the sensation one gets when sniffing an infant presumably feels even more like the feeling of having obtained food. Thankfully for the continuation of our species, this Medean – or is it Swiftian? – impulse is fleeting: the researchers hypothesize that the reward circuit's response evolved to encourage mothers to feed and protect their kids, not to really eat them.

It's unknown whether the increased response among mothers is the result of biological changes to the brain caused by childbirth or a consequence of the new mothers having sniffed their own babies.   

Men were not part of the experiment, so it's still unknown whether baby smells can activate their reward circuits in the same way. Anecdotally, women seem more likely than men to vocalize their baby-eating impulses, but that may just be a difference in how the two genders communicate. 

In any case, smell seems to play an important role in the bond between mothers and their children. After spending no more than an hour with their newborns, 90 percent of mothers can identify their babies by smell alone. Mothers even rank their own babies' No. 2 as No. 1: A 2006 study found that mothers tend to regard the smell of their own baby's poop as less disgusting than that of someone else's baby. 

For their part, newborns are adept at identifying their mothers' particular odor, which they tend to prefer to other odors. 

This latest study adds to a growing body of evidence of how parents and children communicate via their scents, and how  the bonds of affection in the most primary of human relationships is literally wafting through the air.

Story updated

Based on responses to this story, I should probably make something absolutely clear: You should never attempt to actually eat a baby. 

The headline, subhead, and lead to this story are not meant be taken seriously. Together they are, in the parlance of journalism, "the thing that gets people to read the article."

There is never any excuse to harm a child. The impulse that I described in this article does not take the form of an urge to literally bite, chew, and digest a small infant.

Rather, in my experience at least, it arises in utterances such as, "Your baby is so cute I could just eat him all up!" and in behaviors such as placing the baby's toes against the lips and repeatedly uttering the syllable "nom," in an attempt to elicit a giggle from the baby. 

I realize now that such phrases and actions are not actually very common. Or normal.

Still, I hope that you will not only stand firm with me in refraining from infant cannibalism, but that you will also urge your friends, family members, and neighbors to do the same.

-- Eoin O'Carroll, September 24, 2013