Animal Studies in Attachment: Lorenz and Harlow
Lorenz’ Research
In the early 20th century, a number of ethologists (ethology is the scientific study of non-
human animals – it is possible to apply findings to humans?) conducted animal studies of
the relationships between newborn animals and their mothers. Their observations
informed psychologists’ understanding of caregiver-infant attachment in humans. One of
the most prominent ethologists was Konrad Lorenz.
Imprinting
Lorenz (1952) first observed the phenomenon of imprinting when he was a child and a
neighbour gave him a newly hatched duckling that then followed him around (imprinting:
an innate readiness to develop a strong bond with the mother which takes place during
a specific time in development, probably the first few hours after birth/hatching).
Procedure
As an adult researcher, Lorenz set up a classic experiment in which he randomly divided a
large clutch of goose eggs. Half the eggs were hatched with the mother goose in their
natural environment. The other half hatched in an incubator where the first moving
object they saw was Lorenz.
Findings
The incubator group followed Lorenz everywhere whereas the control group, hatched
in the presence of their mother, followed her. When the two groups were mixed up, the
control group continued to follow the mother, and the experimental group followed Lorenz.
This phenomenon is called imprinting – whereby bird species that are precocial / mobile
and able to follow from birth (like geese and ducks) attach to and follow the first
moving object they see. Lorenz identified a critical period in which imprinting needs to
take place. Depending on the species, this can be as brief as a few hours after hatching
(or birth). If imprinting does not occur within that time, Lorenz found that chicks did not
attach themselves to a mother figure.
Sexual imprinting
Lorenz also investigated the relationship between imprinting and adult mate
preferences. He observed that birds that imprinted on a human would often later display
courtship behaviour towards humans. In a case study, Lorenz (1952), described a
peacock that had been reared in the reptile house of a zoo where the first moving
objects the peacock saw after hatching were giant tortoises. As an adult, this bird would
, only direct courtship behaviour towards giant tortoises. Lorenz concluded that this meant
the peacock had undergone sexual imprinting. (see relationships topic)
+ Wellington boot variation – geese followed whoever wore the boots
Harlow’s Research
Harry Harlow carried out perhaps the most important animal research in terms of
informing our understanding of attachment. Harlow worked with rhesus monkeys, which
are much more similar to humans than Lorenz’s birds.
The importance of contact comfort
Harlow observed that newborns kept alone in a bare cage often died but that they usually
survived if given something soft like a cloth to cuddle.
Procedure
Harlow (1958) tested the idea that a soft object serves some of the functions of a mother.
In one experiment, he reared 16 baby monkeys with two wire model ‘mothers’. In one
condition, milk was dispensed by the plain-wire mother, whereas in a second
condition, the milk was dispensed by the cloth-covered mother.
Findings
The baby monkeys cuddled the cloth-covered mother in preference to the plain-wire
mother and sought comfort from the cloth one when frightened (e.g. by a noisy
mechanical teddy bear) regardless of which mother (cloth-covered or plain-wire)
dispensed milk. They even stretched across to the plain-wire mother to feed while still
clinging to the cloth-covered mother. In larger cage conditions, monkeys with cloth-
covered mothers explored more and visited their surrogate mother more often. The results
showed that ‘contact comfort’ was of more importance to the monkeys than food
when it came to attachment behaviour.
Maternally deprived monkeys as adults
Harlow and colleagues also followed the monkeys who had been deprived of a ‘real’
mother into adulthood to see if this early maternal deprivation had a permanent effect.
The researchers found severe consequences. The monkeys reared with plain-wire
mothers only were the most dysfunctional.
However, even those reared with a cloth-covered mother did not develop normal social
behaviour. These deprived monkeys were more aggressive and less sociable than other
monkeys and they bred less often than is typical for monkeys, being unskilled at mating.
When they became mothers, some of the deprived monkeys neglected their young and
others attacked their children, even killing them in some cases.
Lorenz’ Research
In the early 20th century, a number of ethologists (ethology is the scientific study of non-
human animals – it is possible to apply findings to humans?) conducted animal studies of
the relationships between newborn animals and their mothers. Their observations
informed psychologists’ understanding of caregiver-infant attachment in humans. One of
the most prominent ethologists was Konrad Lorenz.
Imprinting
Lorenz (1952) first observed the phenomenon of imprinting when he was a child and a
neighbour gave him a newly hatched duckling that then followed him around (imprinting:
an innate readiness to develop a strong bond with the mother which takes place during
a specific time in development, probably the first few hours after birth/hatching).
Procedure
As an adult researcher, Lorenz set up a classic experiment in which he randomly divided a
large clutch of goose eggs. Half the eggs were hatched with the mother goose in their
natural environment. The other half hatched in an incubator where the first moving
object they saw was Lorenz.
Findings
The incubator group followed Lorenz everywhere whereas the control group, hatched
in the presence of their mother, followed her. When the two groups were mixed up, the
control group continued to follow the mother, and the experimental group followed Lorenz.
This phenomenon is called imprinting – whereby bird species that are precocial / mobile
and able to follow from birth (like geese and ducks) attach to and follow the first
moving object they see. Lorenz identified a critical period in which imprinting needs to
take place. Depending on the species, this can be as brief as a few hours after hatching
(or birth). If imprinting does not occur within that time, Lorenz found that chicks did not
attach themselves to a mother figure.
Sexual imprinting
Lorenz also investigated the relationship between imprinting and adult mate
preferences. He observed that birds that imprinted on a human would often later display
courtship behaviour towards humans. In a case study, Lorenz (1952), described a
peacock that had been reared in the reptile house of a zoo where the first moving
objects the peacock saw after hatching were giant tortoises. As an adult, this bird would
, only direct courtship behaviour towards giant tortoises. Lorenz concluded that this meant
the peacock had undergone sexual imprinting. (see relationships topic)
+ Wellington boot variation – geese followed whoever wore the boots
Harlow’s Research
Harry Harlow carried out perhaps the most important animal research in terms of
informing our understanding of attachment. Harlow worked with rhesus monkeys, which
are much more similar to humans than Lorenz’s birds.
The importance of contact comfort
Harlow observed that newborns kept alone in a bare cage often died but that they usually
survived if given something soft like a cloth to cuddle.
Procedure
Harlow (1958) tested the idea that a soft object serves some of the functions of a mother.
In one experiment, he reared 16 baby monkeys with two wire model ‘mothers’. In one
condition, milk was dispensed by the plain-wire mother, whereas in a second
condition, the milk was dispensed by the cloth-covered mother.
Findings
The baby monkeys cuddled the cloth-covered mother in preference to the plain-wire
mother and sought comfort from the cloth one when frightened (e.g. by a noisy
mechanical teddy bear) regardless of which mother (cloth-covered or plain-wire)
dispensed milk. They even stretched across to the plain-wire mother to feed while still
clinging to the cloth-covered mother. In larger cage conditions, monkeys with cloth-
covered mothers explored more and visited their surrogate mother more often. The results
showed that ‘contact comfort’ was of more importance to the monkeys than food
when it came to attachment behaviour.
Maternally deprived monkeys as adults
Harlow and colleagues also followed the monkeys who had been deprived of a ‘real’
mother into adulthood to see if this early maternal deprivation had a permanent effect.
The researchers found severe consequences. The monkeys reared with plain-wire
mothers only were the most dysfunctional.
However, even those reared with a cloth-covered mother did not develop normal social
behaviour. These deprived monkeys were more aggressive and less sociable than other
monkeys and they bred less often than is typical for monkeys, being unskilled at mating.
When they became mothers, some of the deprived monkeys neglected their young and
others attacked their children, even killing them in some cases.
