Animal Studies of Attachment

Question 1

Lorenz’s research - imprinting

Answer 1

Procedure
Lorenz set up a classic experiment in which he randomly divided a clutch of goose eggs. Half the eggs will hatch with the mother goose in their natural environment. The other half hatched in an incubator were the first move and 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 mobile from birth attach to and follow the first moving object they see. Lorenz identified the 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 in a human would often later display courtship behaviour towards humans. In a case study Lorenz (1952) described a peacock that had been tested 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 concludes this meant the peacock had undergone sexual imprinting.

Question 2

Evaluation of Lorenz’s research

Answer 2

• Lorenz was interested in imprinting in birds. Although some of his findings have influenced our understanding of human development, there is a problem in generalising from findings on birds to humans. It seems that the mammalian attachment system is quite different from that in birds. For example, mammalian mothers show more emotional attachment to young than birds do, and mammals may be able to form attachments at any time, albeit less easily than in infancy. This means that it is not appropriate to try to generalise any of Lorenz’ ideas to humans.
• Later researchers have questioned some of Lorenzo’s conclusions. Take, for example, the idea that imprinting has a permanent affect on mating behaviour. Guiton et al. (1966) found that chickens imprinted on yellow washing up gloves would try to mate with them as adults (as Lorenz would have predicted), but that with experience they eventually learned to prefer mating with other chickens. This suggest that the impact of imprinting on mating behaviour is not as permanent as Lorenz believed.

Question 3

Harlow’s research - the importance of contact comfort

Answer 3

Procedure
Harlow (1958) tested the idea that a soft objects of some of the functions of a mother. In one experiment he read 16 baby monkeys with two wire model ‘mothers’. In one condition milk was dispensed by the plain wire mother where as in a second condition the milk was dispensed by a cloth-covered mother.
Findings
It was found that the baby monkeys cuddle the soft object in preference to the wire one and sought comfort from the cloth one when frightened regardless of which dispense 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
Harlow and colleagues also follow the monkeys who had been deprived of a real mother into adulthood to see if this early maternal deprivation had a permanent effecy. The researchers found severe consequences. The monkeys reared with wire mothers only werr the most dysfunctional; however, even those reared with a soft toy substitute did not develop normal social behaviour. They were more aggressive and less sociable than other monkeys and they bred less often then is typical for monkeys, being unskilled at mating. As mothers, some of the deprived monkeys neglected their young and others attacked the children, even killing them in some cases.

The critical period for normal development
Like the Romans, Harlow concluded that there was a critical period for this behaviour – a mother figure had to be introduced to an infinite monkey within 90 days for an attachment to phone. After this time attachment was impossible and the damage done by early deprivation became irreversible.

Question 4

Evaluation of Harlow’s research

Answer 4

+ Harlow’s findings have had a profound effect on psychologists’ understanding of human mother-infant attachment. Most importantly Harlow showed that attachment does not develop as the result of being fed by a mother figure but as a result of contact comfort.
+ The insight into attachment from Harlow’s research has had important applications in a range of practical contexts. For example, it has helped social workers understand risk factors in child neglect/abuse and so intervene to prevent it (Howe 1998).
- Harlow faced severe criticism for the ethics of his research. The monkeys suffered greatly as a result of Harlow’s procedures. This species is considered similar enough to humans to be able to generalise the findings, which also means that the suffering was presumably quite human-like. Harlow himself was when aware of the suffering he caused – Harlow referred to the wire mothers as ‘iron maidens’ after a mediaeval torture device. The counter argument is that Harlow’s research was sufficiently important to justify the effects.