Recently a pregnant friend who's five weeks from her due date solemnly acknowledged it was time: She and her partner had long ago agreed that he would never make her get rid of any of her shoes, but now she was willing to do so of her own accord. They needed to create space in their lives for the baby to inhabit.
A newly published study from McMaster University in Canada focused on this so-called nesting behavior - an instinctive drive, particularly strong in the third trimester of pregnancy, to clean, organize, and prepare the home for the forthcoming family addition.
From the paper (subscription required), which appears in the journal Evolution & Human Behavior:
In altricial mammals, “nesting” refers to a suite of primarily maternal behaviours including nest-site selection, nest building and nest defense, and the many ways that nonhuman animals prepare themselves for parturition are well studied. In contrast, little research has considered pre-parturient preparation behaviours in women from a functional perspective.
A release describes scientists' exploration of the psychology behind nesting behavior in humans:
They designed two separate studies: a large online study comparing pregnant and non-pregnant women and a longitudinal study tracking women throughout pregnancy and into the postpartum period.
Non-pregnant women -- who acted as the control group -- were compared at similar time intervals, using a questionnaire which was developed, in part, from interviews conducted with midwives.
The study authors found that women exhibit nesting behaviors of preparing space and becoming more socially selective, similar to nonhuman mammals, which may serve as a protective function. "Nesting is not a frivolous activity," said lead author Marla Anderson in the release, adding that "providing a safe environment helps to promote bonding and attachment between both the mother and infants."
Meanwhile, my friend the mom-to-be, who describes her behavior more as a practical matter of space conservation than maternal nesting instinct, said of her shoe-shedding, "Right now I'm agreeing to two pairs. It will probably be more like a half-dozen. We'll see!"