Animal studies in attachment

imprinting definition

an innate readiness to develop a strong bond with the mother which takes place during a specific time in development, most likely the first few hours after birth/ hatching.

imprinting study

a - to investigate Imprinting

p - Lorenz (an ethologist studying animal behaviour) took a clutch of gosling eggs and divided them into two groups. One group was left with their biological mother while the other eggs were placed in an incubator. When the incubator eggs hatched the first living (moving) thing they saw was Lorenz and they soon started following him around. To test this further, Lorenz marked the two groups to distinguish them and placed them together.

f - He found the goslings he looked after had imprinted on him despite their biological mother being present. Lorenz's brood showed no recognition of their natural mother.

Lorenz noted the process of imprinting is limited by a critical period. If a young animal is not exposed to a moving object during this early critical period (usually the first 2 days) the animal will not imprint and form an attachment.

Lorenz also noted that this early imprinting had an effect on mate preferences called sexual imprinting. Animals (especially birds) will choose to mate with the same kind of object upon which they were imprinted.

c - the study supports the idea of imprinting and that there is a critical period in which this must occur.

imprinting study evaluation summary

• supporting evidence

• can’t be generalised to humans

• more flexible than thought

imprinting study evaluation - supporting evidence

Supporting evidence can be found in Guiton's research. He demonstrated that leghorn chicks exposed to yellow rubber gloves for feeding them during their first few weeks, imprinted on the gloves. This shows that young animals imprint on any moving object that is present during their critical period. Guiton also found that male chickens later tried to mate with the gloves, showing that early imprinting is linked to later reproductive behaviour.

imprinting study evaluation - can’t be generalised to humans

Animal studies cannot generalise to humans because humans are capable of more complex thought processes. Human behaviour is governed by conscious decisions. Humans are born much more helpless and "incomplete" with a very immature brain compared with birds. The bonding and growing take place over longer periods of time. However, animal studies can be a useful pointer in understanding human behaviour, but we should always seek to replicate research in humans.

imprinting study evaluation - more flexible than thought

Previously imprinting was seen as a process that was rigid and irreversible, however now it's seen as more flexible. E.g. Guiton found that he could reverse the imprinting in chickens who had initially tried to mate with the rubber gloves. He found after spending time with their own species, they were able to engage in normal sexual behaviour with other chickens. Therefore, Lorenz's theory is too simplistic as fails to take into account later learning

Harlow (1959) - attachment based on comfort or feeding

A: to investigate whether attachment is based on comfort or feeding

P: Harlow created two artificial 'mothers' with different heads. One was made of wire and fed the monkey using a milk bottle whereas the other was covered in soft cloth, and also fed the monkey. Other versions of the monkeys had no feeder bottle. Eight infant Rhesus monkeys were studied for a period of 165 days. They were placed in a cage with both a wire and cloth covered mother. For 4 of the monkeys the milk bottle was on the cloth covered 'mother' and for the other 4 monkeys the milk bottle was on the wire 'mother'. The amount of time each infant spent with the two different' mothers was measured Observations were made of the infant responses when scared by a mechanical teddy bear.

F: All 8 monkeys spent most of their time with the cloth-covered mother whether or not this had the feeding bottle. Those monkeys who fed from the wire monkey only spent a short amount of time getting milk and then returned to the cloth-covered mother. When frightened, all monkeys clung to the cloth-covered mother and when playing with new objects the monkeys often kept one foot on the cloth-covered mother for reassurance.

C: Therefore these findings show infants do not develop an attachment to the person who feeds them but to the person offering contact comfort.

Harlow - long lasting effects

Later Harlow reported that the motherless monkeys developed abnormally even when they received contact comfort. They were socially abnormal; they froze or fled when approached by other monkeys.

They were also sexually abnormal; they did not show normal mating behaviour and did not cradle their own babies. Also found a critical period for these effects. If the motherless monkeys spent time with their monkey peers before they were 3 months old, they seemed to recover. If monkeys spent more than 6 months with the wire monkey they could not recover.

Harlow evaluation summary

• justified

• difference in mothers heads

• can’t generalise to humans

• ethical issues

Harlow evaluation - justified

This experiment can be justified to an extent as it had an effect on our understanding of the processes of attachment and has led to better care for human and primate infants.

Harlow evaluation - differences in mother’s heads

One criticism is that the artificial mothers' varied. The two heads were different which may act as a confounding variable. It is possible that the reason the infant monkeys preferred one mother to the other was because the cloth covered mother had a more attractive head. Therefore, the conclusions lack internal validity.

Harlow evaluation - can’t be generalised to humans

Animal studies cannot generalise to humans because humans are capable of more complex thought processes. Human behaviour is governed by conscious decisions. However, the observations seen in animals are also mirrored in humans. E.g. Harlow's monkey study is supported by Schaffer and Emerson who found infants were not most attached to the person who fed them. Therefore, animal studies can be a useful pointer in understanding human behaviour, but we should always seek to replicate research in humans.

Harlow evaluation - ethical issues

Ethical issues: the study created lasting emotional harm as the monkeys later found it difficult to form relationships with their peers. However, it could be argued that these animal experiments are necessary as they could never be carried out on humans. A human baby could not be separated from its mother merely for the sake of an experiment. Instead, we have to rely on very rare cases of extreme neglect such as the case study of Genie who was abandoned in a room in her house for the first 13 ½ years of her life. As these awful case studies happen so infrequently, we need to use experiments such as Harlow's to understand certain aspects of behaviour.