Mothers Eating Their Babies? – No, It’s Not Cannibalism…
If you’ve ever seen someone with a baby, chances are you’ve heard them say something along the lines of “You’re so cute; I could just eat you up!”
Well a recent article published in Frontiers in Psychology by a research team at the Technische Universität of Dresden, Germany shows there may be a link between an infant’s smell and a female’s response, depending on the status of the female. Scientists have studied the connection between olfactory signals and the bond between a mother and her infant in several non-human mammal species. However, up until now, the research performed on mother-infant bonding in humans has only ever explored the visual and auditory senses.
What they did:
A total of 30 women were tested. Fifteen of the women had given birth for the first time three to six weeks prior to the experiment (primiparous). The other 15 women had never given birth (nulliparous). To obtain the sample odors, 18 infants each wore a T-shirt for two nights postpartum. The shirts were then placed in plastic bags and frozen to keep the odor unaltered. During the experiment, each woman was exposed to both “odorless” air and the odors of two different infants; primiparous women were never exposed to their own baby’s odor. The women were asked to rate the odor on intensity, familiarity, and pleasantness, though none of the participants were aware of what the odor stimulus was. As the women processed the different odors, an fMRI machine scanned their brain.
What they found:
Overall the women rated the infant odors as “weak, unfamiliar, and mildly pleasant”. The researchers found no significant difference in the overall ratings of intensity, familiarity, and pleasantness between the primiparous women and the nulliparous women. Despite the relatively “weak” rating of the odor, they did however find a difference in brain activity. The caudate nucleus of the primiparous women were significantly more responsive to the neonatal odors than those of nulliparous women. When compared to the responses of “odorless air,” the nulliparous women did show increased activity in the caudate nucleus, indicating that the neonatal odors trigger an effect (though not as great) in females who aren’t mothers. The definite contrast between the two groups, suggests that the effects are dependent on the status of the female.
The caudate nucleus, of which dopamine is the chief neurotransmitter, has already been linked to reward learning mechanisms. Through dopaminergic pathways, our bodies can learn to associate certain behaviors with a positive feeling, prompting us to act in a certain way. In this case, females are motivated to show motherly behavior because these actions have been associated with pleasure. The same “circuit makes us desire certain foods and causes addiction to tobacco and other drugs,” says postdoctoral researcher and lecturer at the University of Montreal, Johannes Frasnelli. “Not all odors trigger this reaction. Only those associated with reward, such as food or satisfying a desire, cause this activation.”
The research on this topic is just getting started. This experiment left several questions unanswered, such as what effect do neonatal odors have on males? There also wasn’t any control odor that triggered the same response as the neonatal odors, so the direct link to reward mechanisms needs to be further researched. However, previous studies have shown similar brain activation in the responses of women looking at baby faces. The fact is that babies rely on these behavioral effects for survival.
Babies can’t care for themselves, and when you think about babies objectively, they don’t do much. They eat. They sleep. They cry. They poop. And yet, sleep deprived mothers continue to care for, nurture, and protect their babies. And much of it has to do with the seemingly inexplicable mother-child bond that teaches the body to reward these affectionate parental behaviors with a pleasurable sensation. So it makes sense that the satisfaction a hungry teenager gets from devouring an entire pizza is equal to that of a mother caring for her baby. Since these sensations both work along dopaminergic pathways it’s no wonder we sometimes think babies smell good enough to eat. Luckily for us these are only ephemeral sensations that we thankfully can resist. Otherwise, well, some of us might not be here…
Babies Smell Delicious – NPR
Maternal Response – Frontiers in Psychology
Good Enough to Eat – DailyMail