Some of the ways that mothers can teach offspring is pretty primal: Learning the smell of fear: Mothers teach babies their own fears via odor, animal study shows — ScienceDaily.
Babies can learn what to fear in the first days of life just by smelling the odor of their distressed mothers, new research suggests. And not just “natural” fears: If a mother experienced something before pregnancy that made her fear something specific, her baby will quickly learn to fear it too — through the odor she gives off when she feels fear.
In the first direct observation of this kind of fear transmission, a team of University of Michigan Medical School and New York University studied mother rats who had learned to fear the smell of peppermint — and showed how they “taught” this fear to their babies in their first days of life through their alarm odor released during distress.
This study reminds me of one I linked to a few months ago which appeared to show that mice could inherit a fear of smell from their father. Both studies tried to address the actual phenomenon in humans where children sometimes inherit trauma about experiences that their parents had.
One difference between these studies is that in the earlier one, the offspring were never exposed to the smell until they were tested. That seemed to show that they could only have inherited the fear of that smell genetically. I thought I had remembered that the offspring in that earlier study were also isolated from their parents, but looking it over again, I don’t see that mentioned. (I do see it mentioned that some of the offspring were conceived through in vitro fertilization, which does seem to imply isolation.)
The question is, which of these transmission mechanisms, communication of a parent’s fear to their baby through smell, or the apparent transmission of that fear through sperm or egg, is most relevant to the human phenomenon?
Going forward, he hopes to work with U-M researchers to observe human infants and their mothers — including U-M psychiatrist Maria Muzik, M.D. and psychologist Kate Rosenblum, Ph.D., who run a Women and Infants Mental Health clinic and research program and also work with military families. The program is currently seeking women and their children to take part in a range of studies.
The problem here will be in knowing that the transmission didn’t happen by the mechanism identified in the earlier study. This will be difficult to determine in humans, since you can’t exactly isolate human children from their parents in the manner possible with animals (for obvious ethical reasons).