Although the fact that mortality and morbidity rates for children separated from their mothers are higher than those for children who are not maternally deprived has been clearly established, exactly which essential factors the mother provides remain unknown. Certainly there must be factors other than food, clothing, and warmth, since these are provided for infants in institutions.
The ingenious series of experiments described in this article show that baby monkeys “love” something soft and warm, that ever-present soft, warm artificial mothers seemed initially to be superior to natural mothers. Anyone who has seen how chickens, kittens, mice, or sheep huddle together, even on warm days, or who has observed the strong attachment an infant can develop to a tattered old blanket or a doll, can verify this snuggling response.
A charming lady once heard me describe these experiments; and, when I subsequently talked to her, her face brightened with sudden insight: “Now I know what’s wrong with me,” she said, “I’m just a wire mother.” Perhaps she was lucky. She might have been a wire wife.
Similarly, the mother or mother surrogate provides its young with a source of security, and this role or function is seen with special clarity when mother and child are in a strange situation. At the present time we have completed tests for this relationship on four of our eight baby monkeys assigned to the dual mother surrogate condition by introducing them for three minutes into the strange environment of a room measuring six feet by six feet by six feet (also called the “open-field test”) and containing multiple stimuli known to elicit curiosity responses in baby monkeys.
The neonatal and infant macaque monkey is one subject for the analysis of basic affectionate variables. It is possible to obtain precise measurements in this primate beginning at two to ten days of age, depending upon the maturational status of the individual animal at birth. The macaque infant differs from the human infant in that the monkey is more mature at birth and grows more rapidly; but the basic responses relating to affection, including nursing, contact, clinging, and even visual and auditory exploration, exhibit no fundamental differences in the two species. Even the development of perception, fear, frustration, and learning capability follows very similar sequences in rhesus monkeys and human children.
Three years’ experimentation before we started our studies on affection gave us experience with the neonatal monkey. We had separated more than 60 of these animals from their mothers 6 to 12 hours after birth and suckled them on tiny bottles. The infant mortality was only a small fraction of what would have obtained had we let the monkey mothers raise their infants. Our bottle-fed babies were healthier and heavier than monkey-mother-reared infants.
