"Thus, by this ingenious research we learned what had been totally obvious to everyone else, except psychologists, for centuries."
—Harry Harlow, PhD
Former head of the Primate Research Center at the University of Wisconsin, referred to as “the Dean of Primate Research”
Psychological research includes a shocking history and continuation of maternal deprivation experiments on animals. While maternal deprivation experiments have been conducted far more frequently on rhesus macaques and other monkeys, chimpanzees were not spared as victims of this unnecessary research.
Psychologists like the infamous Harry Harlow inflicted unimaginable emotional suffering on hundreds of primates by separating them from their mothers at various early ages.
After separating infants from their mothers, researchers like Harlow and his protégés left the infants with “surrogate mothers” including devilish man-made devices that ejected barbed spikes, or had freezing temperatures, or rocked so violently the young infants’ teeth chattered as they desperately clung to “her.”
Harlow’s research led to the conclusion that infants will cling to the one thing they identify as their source of contact comfort – the one thing they identify as “mother.” They will cling to their surrogate mother at all costs rather than be left completely alone and separated from this physical contact.
John Bowlby, who studied World War II infants who died in orphanages despite adequate nutrition and health, had already informed the world (years before Harlow’s cruel research) of the literally life-saving need that infants have for contact. His observations of war orphans proved that without some form of warm, physical contact and comfort, the infants died despite adequate care of physical needs.
In some studies, young chimpanzees separated from their mothers were kept in bare wire cages or isolation cubicles that restricted their sensory input and social interaction. Some partial isolation experiments on older chimpanzee children lasted as long as four years.
Most of the chimpanzee maternal separation/deprivation experiments were conducted by researchers R. K. Davenport, C.M. Rogers, and E.W. Menzel at the Yerkes Laboratories in Florida, and the succeeding Yerkes National Primate Research Center in Georgia. However, G. Berkson and W.A. Mason also conducted a smaller number of experiments at the New Iberia Research Center.
Examples of types of maternal deprivation studies
- Chimpanzees, exposed to partial isolation for two to four years, were then exposed to “mild stress” to assess their reactions
- Adolescent chimpanzees who had been maternally deprived in infancy/youth were given LSD to see if it might have a therapeutic effect
- Maternally deprived infant chimpanzees were used to study the effects of food deprivation and administration of amphetamines on their behavior
- Chimpanzee infants/children were deprived of their chimpanzee mother and given to a human to be raised (cross-fostering)
Given the intensity of the mother-child bond for chimpanzees in the wild, this research ranks among the cruelest of all.
It is a known fact that to capture a chimpanzee infant in the wild, his/her mother will inevitably have to be killed – so strong is her instinct to protect her baby – along with several if not all the adults of the group. Free-living chimpanzee mothers are exceptionally protective and caring, and any deviation from this is the result of aberrant behavior. (See our video bibliography list for the film: People of the Forest.)
Ripping infants from their mothers to study the sad effect this has on their emotional, social, and cognitive development and well-being is like dropping apples again and again to continually prove the theory of gravity.
Chimpanzees subjected to laboratory confinement and biomedical research and testing exhibit trauma-induced symptoms. Those who were cross-fostered (that is, taken from their biological mother and raised by a human mother substitute for future use in biomedical research) show additional symptoms peculiar to their early developmental history: compromised ability to socialize with other chimpanzees; dominant behavioral traits reflective of human culture; and, a preference to socialize with humans rather than other chimpanzees.
Human psychological and sociological data is replete with information about the importance of maternal bonding and the consequences to the human child when it is disrupted. Yet, apparently there are scientists who support “apple-dropping” types of experiments which simply show over and over an already-known phenomenon so that some researcher somewhere can continue to use animals, be funded, demonstrate already known facts, and call it “research.”
Senseless maternal deprivation studies on baby monkeys are set to start again at the University of Wisconsin-Madison. Learn more and how to help prevent this cruel and wasteful study here.
Berkson G and Mason WA. 1964. “Stereotyped behaviors of chimpanzees: Relation to general arousal and alternative activities.” Perc. Motor Skills 19: 635-652.
Capaldo, T. 1983 “Maternal Deprivation: An Overview of Animal Research,” unpublished, pp. 2-5.
Davenport RK and Menzel EW Jr. 1963. “Stereotyped behavior of the infant chimpanzee.” Arch Gen Psychiat, 8:99-104.
Davenport RK, Menzel EW Jr. and Rogers CM. 1961. “Maternal care during infancy: its effect on weight gain and mortality in the chimpanzee.” Amer J Orthopsychiat 31:803-809.
Davenport RK, Menzel EW Jr. and Rogers CM. 1966. “Effects of severe isolation in “normal” juvenile chimpanzees.” Arch Gen Psychiat 14:134-138.
Davenport RK, and Rogers CM. 1968. “Intellectual performance of differently reared chimpanzees: 1. Delayed response.” Am J Ment Defic 72:674-680.
Davenport RK, and Rogers CM 1970. “Differential rearing of the chimpanzee. A project survey.” Pp 337-360 in The Chimpanzee, Vol. 3 (G.H. Bourne, ed.) Basel: S. Karger.
Davenport RK, Menzel EW Jr. and Rogers CM. 1969. “Intellectual performance of differentially reared chimpanzees: II. Discrimination-learning set.” Am J Ment Defic 73:963-969.
Davenport RK, Rogers CM and Rumbaugh, DM. 1973. “Long-term cognitive deficits in chimpanzees associated with early impoverished rearing.” Devel Psychol 9:343-347.
Menzel EW Jr. 1964. “Patterns of responsiveness in chimpanzees reared through infancy under conditions of environmental restriction.” Psychol Forsch 27:337-365.
Menzel EW Jr., Davenport RK, and Rogers CM. 1963a. “The effects of environmental restriction upon the chimpanzee’s responsiveness to objects.” J Comp Physiol Psychol 56:78-85.
Menzel EW Jr., Davenport RK, and Rogers CM. 1963b.”The effects of environmental restriction upon the chimpanzee’s responsiveness in novel situations.” J Comp Physiol Psychol 56:329-334.
Menzel EW Jr., Davenport RK, and Rogers CM. 1970. “The development of tool-using in wild-born and restricted-rearing chimpanzees.” Folia Primatol 12:273-283.
Stephens, Martin L. 1986, “Maternal Deprivation Experiments in Psychology: A critique of animal models”, A report prepared for the American, the New England, and the National Anti-Vivisection Societies, pp 27-29.