The Midas Touch
Preemies receive long-lasting cognitive and emotional benefits from being held.
Posted Dec 27, 2013
The findings, from Ruth Feldman, Zehava Rosenthal and Arthur Edelman at Bar-Ilan University in Jerusalem, are the first to show such a long-lasting benefit from early-life touch in humans. They also fit with previous work suggesting that the human brain has critical developmental windows, and experiences within these windows have profound effects on brain function later in life.
Between 1996 and 1998, the researchers recruited 146 mothers in several Israeli hospitals who had given birth 5-15 weeks before their due date. At one hospital, 73 preemies received standard care, which at the time meant placing the child in an incubator. At another, 73 mothers gave Kangaroo Care, meaning that for one hour daily across two weeks, they held their child to their chest while they sat in a rocking chair. Aside from these 14 hours, the groups received identical care. The groups were matched for age, gender, demographic and socioeconomic status. The hospitals had identical nurse-to-patient ratios and number of admissions.
Since preemies haven’t finished developing before birth, they often cannot regulate their body temperature. Incubators stabilize the amount of heat the child receives to keep them warm and also protects them from infection, noise and light. They also deprive infants of their mother’s touch. Harry Harlow’s famous studies in monkeys from the 1960s suggest that touch soothes baby monkeys—and presumably baby humans too—and helps them form a bond.
Kangaroo Care was developed to keep babies warm in hospitals where incubators were unavailable—human caregivers provided warmth to babies who had trouble regulating their body temperature. But rather than a cheap substitute, it provided some important advantages. It led to lower risk of infection and healthier heart function during the first months of life. However, no studies had followed infants long enough to know how Kangaroo Care impacted development throughout childhood.
At age 10, 55 children who received Kangaroo Care and 62 who received standard care completed an IQ test, the Weschler Intelligence Scale for Children. The Kangaroo Care group scored an average of 3 points higher than the standard care group, but the differences were not significant.
The ten-year olds also completed part of a developmental neuropsychological test, the NEPSY, that measures executive function. Executive function includes skills such as impulse control, planning and sustained attention, cognitive abilities that indicate a child’s ability to learn and be productive. An average score on the test is 100. The Kangaroo Care group averaged a score of 103, a little over half a standard deviation higher than the standard care group, who averaged 96. For preemies, simply being held for an hour each day led to significantly better executive function at age 10.
In addition to enhanced executive function, the Kangaroo Care group also had a lower response to stress. At age 10, the children were asked to give a 5 minute presentation to three judges who kept a straight face and did not offer any feedback (the Trier Stress test). The children also had to count backwards from 1,022 by 13 as quickly as possible while the judges watched. The standard care group had significantly higher cortisol levels than the Kangaroo Care group after this test, suggesting that they were more unsettled by the experience.
The results provide evidence that, at age 10, Kangaroo Care did not affect general intelligence, but led to better impulse control, planning skills and ability to cope with stress. Both groups had similar levels of smarts, but Kangaroo Care boosted the ability to marshal brain power to accomplish tasks and succeed in school.
The findings, though remarkable, should be interpreted with caution. The Kangaroo Care and standard care groups were at different hospitals. Although the hospitals had no obvious differences, one may have had a more caring staff or comforting ambience. Alternatively, the mothers who gave birth at the Kangaroo Care hospital may have been different from the mothers who gave birth at the standard care hospital. The mothers from both groups were matched on many factors, but may have differed in how they raised their children. However, no evidence suggests any important differences in the groups.
Despite possible alternative explanations, the results provide compelling evidence that simply being held for an hour a day has long lasting benefits. Experiences in the first few weeks of life may have a great impact on the child’s brain far into life. If a mind is worth its weight in gold, mothers can provide the Midas touch.
Image credit: Thomas