• "So far as love or affection is
concerned, psychologists have failed in
their mission. The little we know about
love does not transcend simple
observation, and the little we write
about it has been written better by
poets and novelists." – Harry Harlow,
"The Nature of Love," 1958
Harry Frederick Harlow was an
American psychologist best known for his
maternal-separation and social isolation
experiments on rhesus monkeys, which
demonstrated the importance of care-
giving and companionship in social and
• BORN – October 31, 1905 in Fairfield
• DIED- December 6, 1981 in Tuscon
• EDUCATION- Stanford college (BA and Phd)
and Reed college
• AWARDS – National medal of science for
• WORKED- psychology staff at the University
of Wisconsin (Madison).
• Harlow, H. F. (1950. The effect of large cortical lesions on learned
behavior in monkeys.Science.
Harlow, H. F. (1958). Biological and Biochemical Bases of
Behavior. University of Wisconsin Press.
Harlow, H. F., et al. (1971). The sad ones: Studies in
depression. Psychology Today 4(12), 61-63.
Harlow, H. F. (1973). A variable-temperature surrogate mother for
studying attachment in infant monkeys. Behavior Research Methods
Harlow, H. F. (1975). Lust, latency and love: Simian secrets of
successful sex. Journal of Sex Research 11(2), 79-90.
• Recommended Reading
Best Known For:
• Social isolation experiments with rhesus monkeys.
• His research played an important role in shaping
our understanding of child development, child
care and child rearing.
• His theory, "Learning to Learn", described
the ability of animals to slowly learn a
general rule that could then be applied to
rapidly solve new problem sets.
• He suggested that paying attention to young
children would "spoil" them and that
affection should be limited.
• Harlow's work instead demonstrated the
absolute importance of developing safe,
secure, and supportive emotional bonds with
caregivers during early childhood.
• Many experts at the time also believed that
feeding was the primary force between the
mother-and-child bonds. Harlow's work
suggested that while feedings are important,
it is the physical closeness and contact that
provides the comfort and security that a child
needs for normal development.
• His theory hinged on the universal need
for contact. Harlow's famous wire/cloth
"mother" monkey studies
demonstrated that the need for
affection created a stronger bond
between mother and infant than did
physical needs (food).
• Harlow carried out a number of variations using sixteen
young isolated monkeys who were separated from their
mother a few hours after birth.
• First, he showed that mother love was emotional rather
than physiological, substantiating the adoption-friendly
theory that continuity of care—“nurture”—was a far more
determining factor in healthy psychological development
• Second, he showed that capacity for attachment was
closely associated with critical periods in early life, after
which it was difficult or impossible to compensate for the
loss of initial emotional security.
• The experiment was conducted on 2 groups.
• In the first group, the terrycloth mother provided
no food, while the wire mother did, in the form
of an attached baby bottle containing milk.
• Harlow’s first observation was that monkeys
who had a choice of mothers spent far more
time clinging to the terry cloth surrogates, even
when their physical nourishment came from
bottles mounted on the bare wire mothers.
• This suggested that infant love was no simple
response to the satisfaction of physiological
needs. Attachment was not primarily about
hunger or thirst. It could not be reduced to
• He modified his experiment and made a
second important observation.
• When he separated the infants into two groups
and gave them no choice between the two
types of mothers, all the monkeys drank equal
amounts and grew physically at the same rate.
But the similarities ended there.
• Monkeys who had soft, tactile contact with
their terry cloth mothers behaved quite
differently than monkeys whose mothers were
made out of hard wire.
• Harlow hypothesized that members of
the first group benefitted from a psychological
to members of the second.
• When the experimental
subjects were frightened by
strange, loud objects, such as
teddy bears beating drums,
monkeys raised by terry cloth
surrogates made bodily
contact with their mothers,
rubbed against them, and
eventually calmed down.
• Harlow theorized that they
used their mothers as a
“psychological base of
• In contrast, monkeys raised by wire mesh
surrogates did not retreat to their mothers
when scared. Instead, they threw themselves
on the floor, clutched themselves, rocked
back and forth, and screamed in terror.
• These activities closely resembled the
behaviors of autistic and deprived children
frequently observed in institutions as well as
the pathological behavior of adults confined
to mental institutions,
• Harlow noticed that the monkeys would
spend most time clinging to the cloth
mother and occasionally feeding from the
wire mother. When the monkeys were
stressed by a mechanical toy banging a
drum the monkeys would always run to the
cloth mum for safety suggesting an
attachment. Also the monkeys with only
wire mothers produced water faeces which
was attributed to stress.
• Clearly because Harlow used monkeys it
is difficult to generalize the findings and
conclusions to humans. Critics of
Harlow's claims have observed that
clinging is a matter of survival in young
rhesus monkeys, but not in humans, and
have suggested that his conclusions,
when applied to humans, overestimated
the importance of contact comfort and
underestimated the importance of
• There are also serious ethical issues with
• On the plus side, the theory can
be said to beneficial in that it
has stimulated a lot of research
into the interactions that take
place between parents and
• Since Harlow's pioneering work on
touch, recent work in rats have found
evidence that touch during infancy
have resulted in a decrease in
corticosteroid, a steroid hormone
involved in stress, and an increase in
glucocorticoid receptors in many
regions of the brain