“In our study of psychopathology, we began as sadists trying to produce abnormality. Today, we are psychiatrists trying to achieve normality and equanimity.”
–Harry Harlow
The Rhesus Animal Mother and Her Contributions to Science and Motherhood
The rhesus animal mother has contributed more to our knowledge of human development than most people realize, and at a great cost. Harry Harlow, a contemporary of Abraham Maslow, conducted research using rhesus monkeys that demonstrated the importance of caregiving and companionship in social and cognitive development. In 1932, he began a breeding colony of Rhesus macaques in order to study their natural behavior. He then performed scientific experiments and noted how their behavior changed under certain conditions.
In nature, the rhesus animal mother is diurnal, and raises her young both in trees and on land. They are mostly herbivorous, feeding mainly on fruit, seeds, roots and bark. Females can outnumber males by as much as 4:1, and they have a separate hierarchy from that of the males. For breeding purposes, they exhibit philopatry, which is returning to the same breeding ground repeatedly. Females have very strong matrilineal hierarchies. Her rank depends upon the rank of her mother. A single group of females may have a number of matrilineal lines within the hierarchy. Unlike other species of monkeys, part of the ranking is based on fitness and fertility, which results in younger females often ranking higher than their older sisters.
Males provide resources and protection from predators, so the potential rhesus animal mother attempts to mate with larger males that are most likely to ensure the survival of their young. During the breeding period of up to eleven days, females mate with up to four males. The rhesus animal mother reaches sexual maturity at four years of age, and remains fertile until menopause at age twenty-five. Males, aside from their role as protectors and providers, do not participate in raising their offspring, but maintain peaceful relationships with them.
A rhesus animal mother with an infant and one or more older daughters that have not yet reached child-bearing age often delegate infant care to those daughters. These high-ranking females often reject their infants and mate earlier in the breeding season than usual after having given birth. Some even abuse their infants, investing little time in their development. These behaviors are associated with the increased stress of caring for multiple offspring.
In his study, Harry Harlow reared rhesus monkeys in a nursery setting, rather than with their mothers. This controversial study involved a high degree of maternal deprivation. The rhesus animal mother raised in isolation without its own mother has difficulty accepting contact with infants or exhibiting normal maternal behavior. During these experiments, monkeys were isolated for periods of time ranging from 3 months to up to 15 years, then placed in various settings where their behavior was observed. Abnormal behaviors that resulted from the isolation included blank staring, repetitive motion and circling, and even self-mutilation. Consequently, there was a loud public outcry against the cruelty of these experiments.
One of the reasons for the public outcry is that rhesus monkeys are so close to humans, sharing 93% of our DNA. They also have similar cognitive abilities, including the ability to understand rules, make judgments, and be aware of their own mental states. In 2014, it was reported in India that an unconscious rhesus monkey was revived by another giving it a crude kind of CPR. The results of these studies, although they were obtained in such a cruel manner, provide some important information.
For monkeys that were isolated for six months, it was found that they could achieve complete social recovery by being exposed to younger monkeys that provided peer therapy. It was also found that the experience of touch is extremely important. Monkeys that were touch deprived, in addition to abnormal behaviors, also displayed weakened immune systems. The studies showed an indisputable link between the amount of physical contact such as grooming an infant received in the first six months and its ability to produce antibodies by one year of age. Valuable research is still being conducted with rhesus monkeys, but using far more humane methodology.
One of the most important results of Harlow’s experiments was reducing the influence of childcare “experts” that advocated not spoiling children with too much affection. The human mother owes a debt of gratitude to her distant cousin, the rhesus animal mother, for her sacrifices in demonstrating the true power of a mother’s loving touch.
