Harry Harlow became famous in the 1960s for providing
"scientific" evidence for the obvious fact that taking monkeys
away from their mothers (maternal deprivation) is an extremely
distressing experience for the young. Harlow focused exclusively on the
infants' reactions of distress, depression, and consequential
development of behavioral pathologies, and seemingly overlooked that the
mother also suffers distress when the two are separated permanently for
experimental reasons. The procedure is inhumane and should not be
condoned by Institutional Animal Care and Use Committees.
Although ethically unacceptable, maternal deprivation studies still
are practiced to investigate in even greater detail all possible
distress responses resulting from maternal deprivation. In the last two
years, eight maternal deprivation studies involving 23 different
researchers at seven institutions have been published in scientific
journals. In all eight studies rhesus macaque babies were taken away
from their mothers shortly after birth. They were reared singly for
several weeks and subsequently pair- or group-housed with other
mother-deprived infants.
Various parameters of the mother-deprived infants were then compared
with those of mother-reared infants. The following quotes summarize the
rationale behind the investigations and the scientific
"discoveries" made.
* "Previous research has linked maternal deprivation in infant
monkeys to subsequent social deficits. Little is known, however, about
the development of social competence in monkeys reared with limited
peer interactions as compared to mother- and peer-reared monkeys....
These findings indicate that impoverished early rearing experiences,
such as adult absence and varying degrees of social isolation, are
useful predictors of future social success in rhesus monkeys."
* "Although monkeys with early maternal and social deprivation
show later behavioral and affective deficits compared to their
maternally-reared counterparts, the extent to which these differences
may be captured by subjectively-measured personality ratings remains
relatively unexplored.... We examined the influence of early social
deprivation on personality." Findings were not conclusive.
* "Infant monkeys reared in peer groups or with inanimate
surrogates show deficits in social and affiliative behavior compared
to mother-reared counterparts.... The purpose of this investigation
was to assess the effect of different rearing conditions on
responsiveness to and acquisition of a simple psychomotor task early
in development.... Taken together, these data provide a framework for
further assessment of individual and between-group differences in
responsiveness of animals with different rearing experiences."
* Statistical analysis "showed a trend for peer-reared monkeys
to have smaller brains than mother-reared ... Further study is needed
to illuminate a possible relationship between rearing condition and
brain volume."
* "The experience of control over environmental outcomes
during infancy is essential for development of mastery motivation,
self-efficacy, and optimism....We developed an apparatus to provide
singly-housed, surrogate-peer reared infants with control or no
control over treat delivery?. Due to the success of the pilot study,
these apparatuses will be implemented in future studies."
* "The purpose of this study was to assess the impact of early
rearing and stress-induced rise of plasma cortisol collected during
infancy as biological predictors of adult alcohol consumption in
nonhuman primates....These findings suggest that early rearing
experiences...are useful psychobiological predictors of future high
alcohol consumption among nonhuman primates.... Many unanswered issues
remain regarding the cause and effect relationships between
vulnerability to stress, cortisol production, and alcohol
drinking."
* "Antidepressants are widely used in treating depression and
other behavioral problems in children and adolescents. Little is known
about the long-term effects of these agents, particularly on
physiological systems.... Regardless of the underlying mechanism(s),
the present study indicates that prophylactic treatment against the
negative consequences of social separation with antidepressants in
rhesus monkeys (prior to 1 year of age) was associated with a
significant alteration in several immune parameters 5 years later....
These results should be considered when prescribing commonly used
antidepressants for treatment of childhood disorders."
* "Clinical depression is often characterized by a loss of
interest or pleasure in formerly enjoyable activities [anhedonia]....
All maternally-deprived animals displayed consistent affective display
confusion, huddling, fearfulness, agitation and, in one case sham
self-biting throughout the course of experimentation.... We conclude
that maternally-deprived rhesus monkeys do not display gustatory signs
of anhedonia, but rather of insensitivity to gustatory stimuli.... It
will be of interest in future studies to determine if a similar
phenomenon can be demonstrated in rodents." Forcefully
separating a primate mother from her baby causes severe distress in
both mother and infant and in human and nonhuman primates. Similar
maternal deprivation routinely occurs at dairy factory farms where
calves are removed from their mothers, subjecting both the cow and
calf to extreme psychological distress. It is questionable that the
scientific rationale and findings of the studies mentioned here
justify the psychological suffering they inflicted on rhesus macaque
mothers and their infants.
