L4 - Animal Studies of Attachment Flashcards
(27 cards)
two key animal studies
- Lorenz
- Harlow (1959)
- interested in formation of early bonds between non-human parents & offspring
- behaviours is common to range of species - can apply to humans
Lorenz
- was an ethologist -scientist who studies the behaviour of animals in their natural environment
- observed in 1930’s that most animals will form attachments very soon after birth
Imprinting
- means when a new born attaches to first living thing they see at birth
- happens very soon after birth in a specific time frame (critical period)
- if imprinting doesn’t occur within this time period then the baby will probably never form an attachment
Lorenz aim
to investigate the mechanisms of imprinting where the youngsters follow and form an attachment to the first large moving object they meet
Lorenz method
- split large clutch of greylag goose eggs into two batches
- one hatched by mother naturally, other in an incubator where Lorenz made sure he was the first moving object seen by goslings
- when hatched they were marked and behaviour observed to distinguish
- placed them under an upturned box then removed it and recorded behaviour
Lorenz findings
- immediately after birth naturally hatched goslings only followed their mother & the others Lorenz
- when released from upturned box, same thing happened, incubator hatched ones showed no bond with mother
- bonds were irreversible
- imprinting would only occur between 4-25 hrs (critical period)
Sexual Imprinting
- Lorenz investigated relationship between imprinting & adult male preferences
- observed that birds that imprinted on a human would later display courtship behaviour
- also in 1952 noted several features of imprinting
Lorenz (1952) - several features of imprinting
- process is irreversible
- long-lasting
- described how one of the geese named Martina who imprinted on him used to sleep on his bed every night (may of tried to mate with him)
Evaluation of Lorenz’s research
strengths
- research support
- case study
weaknesses
- characteristics of imprinting
- generalising
research support
- no. of other studies that show imprinting in other species of birds
- Guiton (1966) demonstrated that leghorn chicks, exposed to yellow rubber gloves for feeding them during their first few weeks, became imprinted on the gloves
- also found that male chickens later tried to mate with the gloves
case study
- Lorenz (1952) described a peacock that had been reared in the reptile house of a zoo where the first moving objects seen after hatching were giant tortoises
- as an adult, the bird would only direct courtship behaviour to giant tortoises
- he concluded that he undergone sexual imprinting
characteristics of imprinting
- there is dispute over the characteristics of imprinting
- original concept suggests that an encounter with an object leads it to being irreversibly stamped in the nervous system
- but now it’s understood it can be a more ‘plastic & forgiving mechanism’ (Hoffman, 1996) & can be reversed
- shown by Guiton (1966) - found that the chicken’s behaviour to the yellow’s gloves could be reversed after spending time with it’s own species
generalising
- Lorenz was interested in imprinting birds, so there is a problem of generalising from birds to humans
- seems that the mammalian attachment system is quite different from birds e.g. mammalian mothers show more emotional attachment to young than do birds
- mammals may be able to form attachments at any time rather than a specific critical period (has been debated)
Harlow (1959)
- used rhesus monkeys to see if attachments are primarily formed through food (Learning theory)
- newborns were separated from mothers & raised in cages
- each cage had a ‘baby blanket’ & monkey’s became distressed when blanked was removed, similar to being separated from mothers - suggests attachment isn’t due to food association
Harlow aim
- to test the learning theory by comparing attachment behaviour in baby monkeys given a wire surrogate mother producing milk with those given a soft towelling mother given no milk
Harlow procedure
- used 16 babies, 4 in each condition - harsh ‘wire’ mother & soft ‘towelling mother’
1. Wire mother producing milk, towelling mother producing no milk
2. Wire mother producing no milk, towelling mother producing milk
3. Wire mother producing milk
4. Towelling mother producing milk - amount of time spent with mother & feeding time was recorded
- monkey’s frightened with a loud noise to test for mother preference during stress
- used a larger cage to test monkeys’ exploration
Harlow findings
- preferred contact with towelling mother when given choice, even if it didn’t produce milk
- stretched across to the wire mother to feed while clinging to towelling mother
- monkeys only with wire surrogate had diarrhoea - distress sign
- if frightened by loud noise then clung to towelling mother (if available)
- in larger cage conditions, ones that had towelling mother explored & visited surrogate mother more
Harlow’s Conclusion
- rhesus monkeys have innate, unlearned need for contact comfort - suggests that attachment is to do with emotional security more than food
- contact comfort is associated with lower levels of stress & a willingness to explore, indicates emotional security
Studies supporting Harlow
Harlow et al. (1965)
Harlow & Suomi (1972)
Harlow et al. (1965)
- raised newborn monkeys in total isolation from living beings for 3,6,12,24 months - monkeys showed signs of psychological disturbance - repetitively rocked & hugged own bodies
- when with other monkeys, they were fearful, no social interaction other then attacking them
- harmed themselves - bite arms & legs, pull out hair also had to ability to engage in sexual courtship
- damage degree positively correlated with total time in isolation
- Harlow was keen to see how they would act as parents
How did Harlow investigate them as parents
- devised apparatus called ‘rape rack’
- female monkeys raised in isolation would be tied & forcibly mated
- were awful parents - abused & neglected babies
- one chewed off their own baby’s feet, another crushed baby’s head to a pulp
- suggests social interactions are essential for normal social & emotional development to occur
Harlow & Suomi (1972)
- raised 4 newborn male monkeys in isolation for 6 months
- then placed each one with a normally raised 3mo old female ‘therapist’ monkey for 2 hrs x3 a week, gradually increasing contact time
- after 12mo their behaviour was almost normal & by 3 years of age they’d totally recovered & were able to live among normally raised monkeys
- suggests effects of total isolation are reversible
Evaluation of Harlow’s research
strengths
Theoretical value
Practical value
weaknesses
Ethical issues
Generalisation of animal studies to humans
Theoretical value
- Harlow’s findings had a profound effect on psychologists understanding of human-infant attachment
- most importantly Harlow’s research showed attachment doesn’t occur due to being fed by a mother figure - it’s due to contact comfort
- also showed importance of quality of early relationships for later social development - including ability to hold down adult relationships & successfully rear children
- in other words, importance of internal working model