Specification: Animal studies of attachment: Lorenz and Harlow.

Early research into attachment was often conducted on non-human animals on the basis that there is biological similarity between animals and humans. Therefore, if something was observed in animal attachment behaviour, it stands to reason that it could also be applied to humans. 

Research studies using animal subjects are often seen as more ethical than when conducted with human participants. Since researchers are often interested in seeing results over a life span there are also practical advantages of using animals since they breed faster than humans do. 

Key Study: Lorenz (1935)

Aim: To examine the phenomenon of imprinting in non-human animals (where the offspring follows and forms an attachment bond to the first large moving object they see after birth). 

Method: Lorenz conducted an experiment where he randomly divided greylag goose eggs into two batches. One batch, the control group, was hatched naturally by the mother. The second batch, the experimental group, were placed in an incubator, with Lorenz making sure he was the first large moving object that the goslings saw after hatching. The following behaviour, of either the mother goose or Lorenz, was recorded. 

Lorenz then marked the goslings so he knew in which condition they were hatched and then placed them under an upside-down box. The box was then removed and their following behaviour of the mother goose and Lorenz was recorded again. 

Results: Lorenz found that straight after birth the naturally-hatched goslings followed their mother goose, whereas the incubator-hatched goslings followed Lorenz. When the upside-down box was taken away, the naturally-hatched goslings moved immediately towards their mother, while the incubator-hatched goslings followed Lorenz, showing no attachment to their biological mother. Lorenz noted that this imprinting only occurred within a critical period of 4–25 hours after hatching. This relationship persisted over time and proved to be irreversible. 

Conclusion: These results suggest that imprinting is a form of attachment that is exhibited by birds that typically leave the nest early, whereby they imprint onto the first large moving object they encounter after hatching. 

Evaluation of Lorenz (1935)

Since Lorenz only studied non-human animals – a sample of greylag geese – we cannot generalise the results to humans since we are unable to conclude that they would behave in exactly the same way. The attachment formation in mammals appears to be very different to that of bird species with parents, specifically mothers, showing more emotional reactions to their offspring with the added ability of being able to form attachments beyond the first few hours after birth. So, whilst some of Lorenz’s findings have greatly influenced our understanding of development and attachment formation, caution must be applied when drawing wider conclusions about the results. 

 Later research has cast doubt onto some of the conclusions which Lorenz drew from his research study on imprinting. For example, Guiton et al. (1966) found that chickens would imprint on yellow washing up gloves if that was the largest moving object they first saw after birth and that, in turn, they would then try to mate with that object in adulthood. However, Guiton et al. disagreed with Lorenz’s predictions that this relationship persists and is irreversible since, with experience, the chickens could eventually learn to prefer mating with other chickens instead, suggesting that the effects of imprinting may not be as permanent as initially thought.  

Key Study: Harlow (1959)

Aim: To examine the extent to which contact comfort and food influences attachment behaviour in baby rhesus monkeys.

Method: Harlow constructed two surrogate mothers: one harsh ‘wire mother’ and a second soft ‘towelling mother’. A sample of sixteen baby rhesus monkeys were used across the four caged conditions:

1. ‘wire mother’ dispensing milk and ‘towelling mother’ with no milk. 

2. ‘wire mother’ with no milk and ‘towelling mother’ dispensing milk.

3. ‘wire mother’ dispensing milk.

4. ‘towelling mother’ dispensing milk.

The amount of time the baby rhesus monkey spent with each mother was recorded, alongside how long they spent feeding at each one. To test for mother preference during periods of stress, the monkeys were startled with a loud noise and their responses recorded. A larger cage was used in some conditions in order to observe the degree of exploration by the baby rhesus monkeys. 

Results: Harlow discovered that, when given a choice of surrogate mother, the baby monkeys preferred to make contact with the soft ‘towelling mother’ irrespective of whether she dispensed milk. It was observed that they would even stretch across to the ‘wire mother’ for food whilst still clinging onto the ‘towelling mother’ for contact comfort. The baby monkeys in the condition with only the ‘wire mother’ showed signs of stress such as diarrhoea. When startled by the loud noise, the baby rhesus monkeys would cling tightly to the soft ‘towelling mother’ in the conditions where this surrogate was available to them. When given larger caged conditions, greater exploration behaviour was seen by the baby monkeys with the ‘towelling mother’ surrogate, which is indicative of emotional security. 

Conclusion: Harlow concluded that baby rhesus monkeys appear to have an innate drive to seek contact comfort from their parent suggesting that attachment is formed through an emotional need for security rather than food, which is in contrast to the learning theory explanation. This contact comfort provided by the mother is associated by a higher willingness to explore their surroundings and lower levels of stress.

Evaluation of Harlow (1959)

The results from Harlow’s study is of large practical value since it provides insight into attachment formation. This has important real-world applications that can be useful in a range of practical situations. For example, Howe (1998) reports that the knowledge gained from Harlow’s research has helped social workers understand risk factors in neglect and abuse cases with human children which can then serve to prevent it occurring or, at the very least, recognise when to intervene. In addition, there are practical applications which are used in the care of captive wild monkeys in zoos or breeding programmes to ensure that they have adequate attachment figures as part of their care.  

Harlow was criticised heavily for the ethics of his research on baby rhesus monkeys. The monkeys suffered greatly in terms of emotional separation from their biological mother at such an early age due to the procedure Harlow used. If the species of primates are considered to be sufficiently human-like to generalise the results beyond the sample used then it stands to reason that the effects of psychological harm that they will have endured are similar to that of a human baby also. There is, however, the question of whether the insight obtained was sufficiently important to psychologists’ understanding of attachment that Harlow was justified in his approach.  

There is an issue with applying findings from animal research to humans. Although the participants of Harlow’s research were baby rhesus monkeys which are non-human, it could be argued that they are far more like humans than the geese that Lorenz studied. It is still heavily debated amongst psychologists as to what extent studies of animals, specifically primates, should be generalised to the human population due to their apparent differences.