A study reveals that new mothers can recognize their offspring
by smell and touch alone.
By Daniella Ashkenazy
Many mothers claim to be able to recognize the cry of their newborn infant. But can a mother identify her new baby by its smell? According to Hebrew University psychologist Dr. Marsha Kaitz the answer is yes, but that is not all: new mothers have a special sensitivity that allows them to recognize their own offspring not only by smell but by touch alone.
The findings are the results of a series of studies on mother-baby interactions during the first days after birth conducted by Kaitz and her colleagues, in collaboration with Professor Arthur Eidelman of the Department of Neonatology at the Shaarei Zedek Medical Center in Jerusalem. Kaitz was prompted to examine olfactory and tactile perceptions in the wake of a previous study of goats and ewes, which demonstrated that olfactory cues trigger maternal bonding: female goats and ewes neglected their offspring if prevented from sniffing their newborns during the first hour after their birth.
In the first study, Kaitz asked 42 post-partum mothers who had spent at least one hour with their newborns to sniff three bags containing identical undershirts that had just been removed from three newborn infants one of them from their own child. Every single subject identified her own child by smell.
The discovery of a parallel heightened tactile sensitivity was the result of further research into early bonding mechanisms. With their eyes and noses covered with a heavy scarf, the new mothers participating in the experiment were asked to identify their own offspring from among a group of three babies asleep in their bassinets, solely by touch stroking the skin of the infants hands. Out of 68 participants, 69% selected their own infants, more than double the number that would be expected by random guessing. When asked how they recognized their own baby, a majority cited texture and temperature, but approximately 40% could not cite a specific sensory cue.
Is infant touch recognition the exclusive province of mothers? When Kaitz put 23 fathers to the test identifying their own offspring from among three infants by stroking the back of their hands 61% succeeded in recognizing their own child, well above the 33% one could expect by chance. Kaitz was so intrigued with this result, that she and her colleagues then conducted a subsequent study of tactile behavior of mothers and fathers with their newborn infants.
The style with which parents touch their newborn infants was studied by filming mothers and fathers holding their infants. The video tapes were reviewed, and the parental behavior coded and analyzed. While the study found that the amount and frequency of tactile contact was equal for both parents, mothers tended to touch or stroke their infants a soothing "caretaking" gesture while fathers patted or shook them, behavior closer related to "play".
In a final experiment, Kaitz presented mothers with a list of words some related to babies and some to nature. The mothers were able to remember far more words related to babies, suggesting that mothers memories becomes selective attuned to pertinent data connected to nurturing their young. When the same list was given to female and male students who were not parents, the women remembered more baby-related words than their male colleagues, but their scores where lower than new mothers. According to Kaitz, these results suggest that women are "naturally tuned to infants even before they are mothers, but motherhood puts them more in touch".