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.
