Please forward this error screen to sharedip-1071803110. Getty ImagesA child sleeps with his hand tied to a bar at an orphanage in Ploiesti, Romania, on May 16, 1990. This particular orphanage is group mother and baby early development children who have birth defects, deformities and intellectual disabilities.
Most people don’t need science to appreciate the importance of a mother’s love. But to understand how early maltreatment can derail a child’s development requires careful study — and is fraught with ethical peril. Such research is therefore often conducted in animals. A new analysis of data on 231 rhesus macaque monkeys explored the effects of three early-childhood conditions on the animals’ later lives. About half of the monkeys were raised normally by their mothers, living in social groups with other monkeys — a condition similar to their natural environment.
One quarter of the monkeys were reared in a nursery without their mothers until day 37, when they were placed in groups of four other monkeys of a similar age. The final group was also nursery-raised at first, but then these babies were transferred to a cage, where they spent most of their time, with a hot water bottle covered in terrycloth. Two hours a day, these monkeys were allowed to interact with other monkeys their age. While such experimentation sounds cruel, this type of research has been critical in helping change policies in human orphanages that had for centuries treated infants equally inhumanely. The harrowing consequences of these theories were most vividly brought to light in Romania in the 1980s and ’90s, when a ban on abortion led to a surge in orphanage babies. The longer these children were left in their cribs, simply being fed and changed without individualized affection, the more damage was seen, even if the orphanage was clean and well-run. Many children developed autistic-like behaviors, repetitively rocking or banging their heads.
Still, orphanage advocates blamed pre-existing problems that had led parents to give up the children in the first place, not institutional conditions. This debate continued until researchers were allowed to randomize abandoned infants without clear birth defects to either usual orphanage care or foster care from birth. Nonetheless, the study showed that the children who were placed in foster care developed normally, with appropriate head sizes, and less distress, better attentional skills and a 9-point higher IQ on average, compared with children sent to orphanages. Only after this research was published in 2007 did Romania change its policies, though there are still some countries that continue to place abandoned infants in these dangerous settings. Because the problem persists, and also because other early child abuse and neglect can replicate such situations, ongoing study of what harms children in early childhood and what helps their recovery is needed. In the new research, the monkeys remained in the various rearing conditions — with their mothers, with peers or mainly isolated — until they were about six months old.
That’s the human equivalent of age 3 — when the brain is developing at a faster rate than at any other time in postnatal life. After the 6-month period, the monkeys were placed in a mixed social group, comparable to the normal conditions for their species. They were studied when they were about 1 year old. The results differed by gender, an effect also seen in humans suffering from child maltreatment.
Male monkeys reared in isolation were nearly twice as likely to come down with physical illnesses as those reared by their mothers or with peers. They were also more than five times as likely to show stereotyped behavior, the repetitive motions similar to the rocking or head-banging seen in some cases of autism and in orphanage-reared infants. In females, surprisingly, the peer-reared group did worse than the monkeys raised in isolation. They were far more likely to be wounded and to suffer hair loss than monkeys raised by their mothers or in isolation.
The researchers found that the peer-reared females were more aggressive than other monkeys, suggesting that the wounds may have resulted from fights and the hair loss from hair-pulling by others. While the males had high levels of a stress hormone known as cortisol and low levels of the metabolite of the mood-related neurotransmitter serotonin, this difference was not seen in females. Lead author Gabriella Conti of the University of Chicago suggests that this may be because in the womb, female fetuses are also more resilient than males. High levels of stress hormones can increase risk for both mental and physical illnesses, including depression, which also can involve low levels of serotonin.