Why babies are abandoned
Scientists examine the
evolutionary roots of a horrifying practice
Posted Nov. 18,
A tiny body stuffed into a trashcan in a hotel bathroom in Florida last week told the story. The nameless girl had been born right there in the bathroom, then dumped. Similar sad stories repeat themselves in newspapers worldwide, like a dismal drumbeat; authorities counted 105 such reports of abandoned babies, just in the United States in 1998.
Although no one knows exactly how often or why people abandon their babies, scientists are trying to learn more about the phenomenon by studying animals that do it. In one of the first such studies, researchers have found that maternal inexperience may be a key reason for infant abandonment.
The two researchers found that among captive Japanese macaques, a type of monkey, a mother’s inexperience was by far the most common factor associated with infant abandonment. First-time mothers abandoned about 40 percent of their babies, whereas other mothers abandoned only 1.2 percent of theirs.
Low social ranking also increased a mother’s chances of abandoning her infant among the macaques, although this factor was less important than inexperience, the researchers found.
Although there is no proof that humans abandon their infants for the same reasons as macaques do, the abandonment patterns seem strikingly similar between both species, said Gabriele
Schino, one of the researchers.
“I do believe comparative and evolutionary studies of primate behavior can shed light on human behavior,”
Schino, of the National Research Council, Rome, Italy, wrote in a recent email. “The similarities between human and macaques are in this case rather impressive. To the extent that one can trust the general press, human mothers that abandon their infants appear to be invariably, young, primiparous [mothers for the first time], and with little social support (just like the macaques!)”
A fact sheet published by the University of California at Berkeley's Abandoned Infants Assistance Resource Center in 2002 states that women who kill or abandon their babies are generally “very young, unmarried, physically healthy women who are pregnant for the first time and not addicted to
Schino and Alfonso Troisi, of Tor Vergata University in Rome, studied data on 207 live births among Japanese macaques housed at the Rome Zoo over two decades. The fact that the animals were held in captivity may have distorted the data, they acknowledged, since there is no proof that wild animals behave similarly. On the other hand, they wrote, data from wild monkeys could also be skewed, since many infant abandonments could go undetected in the wild.
Schino and Troisi said their findings also offered some, though not conclusive, support for a long-held evolutionary theory of abandonment. This idea, called the maternal divestment hypothesis, is based on the principle that evolution favors the spread of the organisms that are the best survivors and breeders. Accordingly, evolution would produce females who abandon infants when they sense the infant would compromise their own ultimate breeding success. This might happen if limited resources would force a tradeoff between the baby’s health and their own, or threaten the infant’s own ultimate survival.
Schino and Troisi said their findings support this theory to some extent. They could also simply indicate that abandonment happens because inexperienced mothers don’t know how to handle their babies properly, they said; or both could be true.
Some psychologists have argued that baby abandonment among humans occurs because mothers are in denial. In other words, due largely to social pressures against early or unplanned pregnancies, they never quite accept that they are pregnant at all.
All these explanations might be correct, according to Schino and Troisi, and might be different manifestations of the “maternal divestment” hypothesis.
Amid all this uncertainty, they added, there seems to be one reliable antidote to abandonment, at least among macaques: spending a few hours with an infant. Once a macaque mother has done this, the chances that she will abandon an infant drop to nearly zero, the researchers reported. “In over 20 years of study, no infant was ever abandoned in the days or weeks following its birth: infants were either abandoned immediately after birth or never
abandoned,” the researchers wrote in a paper describing their findings. “It appears that a few hours of interaction are sufficient to establish a close attachment bond between a new mother and its
The paper is due to be published in an upcoming issue of the research journal
American Journal of Physical Anthropology.