Animal studies of attachment
A lot of the early research into attachment theory was performed on animals. Indeed most of the theories that were put forward to explain attachment came out of research performed on animals. One of the earliest explanations of attachment behaviour was that of the learning theory. This saw attachments as being based on feeding and formed from experience with environmental interactions. Support for behaviourist explanations, such as this, came mostly from animal studies. The major theorist into attachment behaviour was John Bowlby. Although he was originally influenced by Freudian psychodynamic thinking, his classic monotropic theory of attachment (see page 45), which explains how attachments are formed and maintained, and his maternal deprivation hypothesis (see page 48), which explains what happens when attachments are broken, were formed from animal studies. The work of Konrad Lorenz centred on the idea of imprinting that saw animals following the first large moving object they encountered. Bowlby came to see attachment as a human form of imprinting. Harry Harlow’s work with rhesus monkeys was also important. Harlow showed, in studies involving separating baby monkeys from their mothers, that behaviourist explanations were wrong and that attachment appeared to be based more on emotional security than feeding.
Fig 3.4 Whooping cranes and their imprinted micro-light aircraft parents
Lorenz (1935) investigated the mechanisms behind imprinting, whereby newborn animals follow the first moving thing they meet. Lorenz split a clutch of goose eggs into 2 batches, 1 of which hatched naturally by the mother and the other hatched in an incubator. Lorenz made sure he was the first moving object the goslings met. He marked each one, so he knew which were naturally hatched and which were incubator hatched. He then placed them all under a box, releasing them simultaneously in the presence of both the mother and himself. Straight after birth, the naturally hatched goslings had followed their mother, while the incubator hatched goslings followed Lorenz. When released from the upturned box, the same behaviour was seen, and these attachments proved to be irreversible. Imprinting only occurred in a ’critical time period’ between 4 and 25 hours after hatching. This suggests that imprinting is a form of attachment that helps young creatures keep close proximity to the first moving object they encounter.
• Harlow (1959) gave baby rhesus monkeys, separated at birth from their mothers, a choice between a harsh wire surrogate mother that provided milk and a soft towelling mother that provided no food. The monkeys preferred the soft towelling mother, using it as a safe base to explore from. This suggests that attachment is based more on emotional security than on feeding.
• Sluckin (1966) performed a variation of Lorenz’s study on ducklings. He found that imprinting would still occur after ducklings had been isolated for 5 days — beyond the established critical time period. This suggests that the critical period is actually a ’sensitive’ (best) period, beyond which imprinting, though more difficult, can still be achieved.
• Harlow et al. (1965) found that newborn monkeys raised in total isolation showed signs of psychological disturbance. The females made very poor mothers, some even killing their babies. This suggests social interactions are essential for normal development.
The shocking results of Harlow et al.’s (1965) study were found to be reversible by Harlow & Suomi (1972). They placed isolated monkeys with an opposite sex younger ’therapist’ monkey, gradually increasing contact time. By 3 years of age they had totally recovered.
The use of animal research enabled psychologists to study attachment behaviour in ways that would not have been practically or ethically possible with human participants.
The results of animal studies enabled psychologists to realise that attachment theories based on feeding were wrong. They led to the much better considered theories of Bowlby that saw attachment as a biological device centred on its survival value.
The problem with animal studies is generalisation: what is true for animals is not necessarily true for humans. Imprinting only occurs in nidifugous birds (ones that leave the nest early), so imprinting behaviour is not representative of most bird species (non-nidifugous species), let alone humans.
There are ethical issues of harm with animal studies, like those of Harlow where many of the monkeys died. Harlow even invented a ’rape rack’, a device to which female monkeys were tied and forcibly mated.
Lorenz’s membership of the Nazi party has led to accusations that his belief in genetically inherited characteristics contaminated his work with researcher bias.
Imprinting research has helped reintroduce migratory birds to areas where they have become extinct. Whooping cranes are imprinted onto micro-light aircraft and taught the traditional migratory flight paths. Farmers also use imprinting by putting an orphaned lamb wearing the skin of a dead lamb with the dead lamb’s mother so that she will accept it.