Animal studies of attachment

Gosling eggs, 2 groups. 1 group left w/ mother, 1 group in incubator. When incubator eggs hatches, first living thing they saw was Lorenz, soon started following him around. Testing effect of imprinting, L marked 2 groups to distinguish them + placed them together; they'd become imprinted on him. Both L + natural mother present.

Goslings divided themselve, 1 group followed natural mother, other followed L. L's group showed no recognition of mother. Noted process of imprinting restricted to definite period of young animal's life - critical period. If not exposed to living thing during critical period, animal won't imprint. Suggests animals can imprint on persistently present moving object seen w/ 1st 2 days. Imprinting is process similar to attachment, binds young animal to caregiver. 

L observed imprinting to humans doesn't occur in some animals eg curlews.

L (1952) - several features of imprinting eg process irreversible + long lasting. 1 of geese who imprinted on him, Martina, used to sleep on his bed every night.

Notes early imprinting had effect on later mate preferences - sexual imprinting. Animals choose to mate w/ same kind of object imprinted on.

Created 2 wire mothers w/ diff head. One wrapped in soft cloth, other plain. Eight infant monkeys studies for 165 days. 4 of monkeys milk bottle on towelling mother, other 4 milk bottle on plain. During time, measurements made of amount of time each infant spent w/ 2 diff mothers. Observations made of responses when frightened eg by mechanical teddy bear.

All monkeys spend most of time w/ towelling mother, whether had feeding bottle or not. Monkeys who fed from wire mother only spent short amount of time getting milk, returned to towelling mother. When frightened, all clung to towelling mother + when playing w/ new obejcts, often kept one foot on towelling mother for reassurance. Suggests infants develop attachment to who offers contact comfort, not who feeds them.

Continued study as grew up, noted consequences of early attachment experiences. Motherless minkeys, even who had contact comfort, developed abnormally - socially abnormal eg froze/fled when approached. Sexually abnormal - didn't show normal mating behaviour, didn't cradle own babies.

Critical period - if motherless monkeys spent time w/ 'peers', seemed to recover, but only if happened before 3 months old. Having 6+ months of wire mother something couldn't recover from.

Guiton (1966) - leghorn chickens exposed to yellow rubber gloves for feeding during 1st few weeks became imprinted on gloves - supports imprinting + critical period. Also found male chickens later tried to mate w/ gloves, shows early imprinting linked to later reproductive behaviour.

Dispute over characteristics of imprinting - original concept, encounter w/ appropriat object -> image of imprint irreversibly stamped on nervous system. Now, seen as more 'plastic + forigiving mechanism'.

Harlow's study, 2 stimulus objects varied in more ways that being cloth-covered or not. 2 heads were diff - acted as confounding variable, therefore conclusions lack internal validity.

Animal studies - can't be fully generalised to human behaviour.

Ethics - monkeys distressed, created lasting emotional harm.