animal studies of attachment Flashcards
lorenz research
in the early 20th century a number of ethologists conducted animal studies of the relationship between new born animals and their mothers.
their observation informed psychologists understanding of caregiver-infant attachment in humans.
imprinting research
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.
procedure - lorenz research
as an adult researcher lorenz set up a classical 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 - lorenz research
the incubator group followed lorenz everywhere whereas the control group, hatched in the presence of their mother, followed her.
when two groups were mixed up the control group continued to follow the mother and the experimental group followed lorenz. this phenomenon is called imprinting.
imprinting
whereby bird species that are mobile 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 specie this could be as brief as few hours after hatching (or birth).
if imprinting does not occur within the 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 an human would often later display courtship behaviour towards humans.
sexual imprinting case study (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.
harlow 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 research
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 - harlow research
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. this showed that contact comfort was of more importance to the monkeys than food when it came to attachment behaviour.
maternally deprived monkeys as adults (1)
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.
maternally deprived monkeys as adults (2)
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 become mothers, some of the deprived monkeys neglected their young and others attacked their children, even killing them in some cases.
the critical period for normal development
like lorenz, harlow concluded that there was a critical period for attachment formation - a mother figure had to be introduced to a young monkey within 90 days for an attachment to form. after this time attachment was impossible and the damage done by early deprivation became irreversible.
