Animal Studies of Attachment
Lorenz's Research
Lorenz‘s research
Konrad Lorenz in 1952 was the first the outline the phenomenon of imprinting.
Procedure
He set up an experiment in which he randomly divided a clutch of goose eggs into two conditions. Half of the eggs were hatched in an incubator while the other half were left to hatch with the mother goose, in the natural environment. When the goslings hatched the first thing they saw if they were in the incubator condition was Lorenz, whereas the other goslings saw their mother.
Findings
Lorenz noticed how the incubator group followed him everywhere while the other group (the Control group) followed the mother goose. At one point he even mixed the two groups up together and noticed that the incubator group sought him out and followed him, whereas the control group would follow their mother.
He called this phenomenon imprinting. This refers to the concept that animals who are altricial and very mobile from birth follow the first moving object that they see. This has a survival purpose as the goslings will follow their mother and be protected from danger. Lorenz also proposed the idea of a critical period. He referred to this as a period of time when imprinting must occur, and that if this did not occur, then it would never happen. He later changed this to a sensitive period when imprinting is most likely to happen.
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Sexual imprinting
Lorenz also suggested that imprinting is important for later adult behaviours. Lorenz (1952) described the case of a peacock that was living in the reptile house of a zoo, that had imprinted on a giant tortoise. When this animal became mature, it would start to try to court the giant tortoises. Lorenz concluded that the peacock had demonstrated sexual imprinting. This gives animals a sense of mate preferences.
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Evaluation
1. One strength of Lorenz’s research is there is other support for the concept of imprinting. Regolin and Vallortiagra in 1995 conducted a study using chicks. They exposed chicks to a simple shape combination after hatching (that moved) and then exposed them to a number of other shape combinations that moved in front of them. The researchers found that the chicks followed the shape combination that closely resembled the one that they were first exposed to after hatching. This study supports Lorenz’s theory that imprinting is a following response, which occurs in a very short period of time after birth.
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2. One limitation of Lorenz’s research is the problem of trying to generalise his findings to humans. Mammals are very different and more complex than birds. For example, in mammals, attachment behaviour is a two-way process between mother and offspring. The concept of imprinting suggests that it is one way – the baby animal imprints on the mother. Furthermore, in mammals there also appears to be an emotional attachment made between the baby and the caregiver, which might not be the case in birds. Therefore, there are issues with trying to generalize Lorenz’s concepts to human behaviour.
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Harlow's Research
Harlow's research
Harry Harlow conducted research in the 1950s with the aim of trying to understand whether food was the primary reason for human attachment.
Procedure
Sixteen rhesus monkeys were separated from their real mothers and then placed in a cage with two wire model ‘mothers’. In one condition, a milk bottle was attached to one of the wire models and in another condition the milk was dispensed by a cloth covered model. Harlow wanted to see which model the monkey would go to. Would it be the model that had the milk bottle attached to it (if food was the basis of attachment) or would it be the cloth covered model?
Findings
Harlow found that the baby monkeys preferred to spend most of the time with the cloth covered ‘mother,’ regardless of whether that model dispensed the food (milk) or not. At one point he put into the cage a mechanical toy to scare the monkeys to see which model they would go to. He found that the baby monkey would run to the cloth covered model, regardless of whether it dispensed milk or not. He concluded that this showed that ‘contact comfort’ was more important than food to the monkeys when it comes to attachment behaviour.
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The monkeys as adults
Harlow also followed the monkeys into adulthood to assess whether this early maternal deprivation had had a permanent effect on the monkeys. He found that the monkeys who were reared by the wire mothers only were the most dysfunctional and had suffered the most severe consequences.
However, he also found that the monkeys with the cloth covered ‘mothers’ also failed to display normal social behavior. He found overall that all of the monkeys that had been deprived of the natural mother were more aggressive and failed to socialise with the other monkeys. He found that even if these deprived monkeys did go on to have babies of their own, they did not know how to look after their children, and sometimes they would even kill them.
Harlow concluded that there was a critical period for attachment formation for monkeys. This appears to be 90 days after the monkey is born. He found that after this time the damage done was irreversible and the monkeys would never have the ability to form strong attachments.
Evaluation
1. One strength of Harlow's research is it has important real world applications. For example, it has been used to help social workers and anybody who works with children to understand what the effects are of poor attachments in childhood. It appears that children who have been neglected suffer consequences that potentially cannot be reversed. This research also helps us to understand the importance of attachment for animals who are born in zoos and as part of breeding programs in the wild.
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2. One problem with Harlows research is that the research was done on animals and therefore we might not be able to generalise his findings and conclusions to humans. Rhesus monkeys were chosen because they are more similar to humans than many other animals as they are mammals and live in social groups. However, human behaviour is far more complex than that of animals.
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3. Another limitation of Harlows research is that of ethics. Harlow’s research led to extreme distress and long term consequences for the monkeys, and some people have suggested that the costs of the research outweigh the benefits. However, some researchers have argued that it has told us something very important about attachment behaviours in humans, which justifies the ethical issues caused for a small sample of monkeys.
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