Animal studies Flashcards
What did Lorenz (1935) study and what was the aim?
Imprinting
Aim = to investigate the mechanisms of imprinting where the youngsters follow and form an attachment to the first large moving object that they met.
What was the procedure of Lorenz’s study?
He split a clutch of grey-lag goose eggs into two batches, one of which was hatched naturally by the mother and the other hatched in an incubator, with Lorenz ensuring he was the first moving object the incubator hatchlings encountered. Their behaviour was then recorded
He then marked all the goslings so he could determine whether they were from the naturally hatched batch or the incubator batch and placed them in an upturned box. The box was then removed and the following behaviour recorded again.
What is imprinting?
A form of attachment where offspring follow the first large moving object they encounter
Why was the Lorenz study important?
Supported imprinting
What were the findings of the Lorenz study?
- Immediately after birth, the naturally hatched baby goslings followed their mother about while the incubator hatched goslings followed Lorenz about
- When released from the upturned box the naturally hatched goslings went straight to their mother while the others went straight to Lorenz showing no bond with their natural mother (these bonds proved irreversible with the naturally hatched goslings only following their mother and the incubator ones only Lorenz
- Lorenz also noted how imprinting would only occur in a brief time period of about 4-25 hours after hatching
- Goslings that imprinted on humans would, as mature birds, attempt to mate with humans
What conclusions can be drawn from Lorenz’s study?
Imprinting is a form of attachment, exhibited mainly by nidifugous birds (ones that leave the nest early) whereby close contact is kept with the first large moving object encountered.
What other research does Lorenz’s study link to?
Harlow and the monkeys
Bowlby’s MDH and continuity theory
What is the evaluation of the Lorenz study?
The fact that imprinting is irreversible suggests that ability is under biological control as learned behaviours can be modified by experience
The fact that imprinting only occurs within a brief, set time period influenced Bowlby’s idea of a critical period in human babies ( a specific time period within which an attachment between infant and carer must form
The fact that goslings imprinted onto humans exhibit sexual advances to humans when adult birds shows the importance of the behaviour upon future relationships , something Bowlby incorporated into his continuity hypothesis.
There are extrapolation issues with animal studies (attachment behaviour of geese is not necessarily representative of that of humans as they differ very much
Humans altricial and animals are precocial so the development of attachments and the purpose of these attachments may be very different
What is altricial?
Born at an relatively early stage of development and need to form attachment bonds to make sure they survive
What is precocial?
Born at an advanced stage of development e.g. able to walk/ swim
What was Harlow’s study (1959) about and what was the aim?
Even baby monkeys need comfort more than food
Aim = to test learning theory by comparing attachment behaviour in baby monkeys given a wire surrogate mother producing milk with those given a soft towelling mother producing no milk
What was the procedure of Harlow’s study?
Two types of surrogate mother constructed, a harsh wire mother and a soft towelling mother - 16 baby monkeys were used with four in each of the four conditions
1. A cage containing a wire mother producing milk and a towelling mother producing milk
2. A cage containing a wire mother producing no milk and a towelling mother producing milk
3. A cage containing a wire mother producing milk
4. A cage containing a towelling mother producing milk
As well as this, time spent with each mother and feeding time was recorded, monkeys were frightened with a loud noise to test mother preference during stress, a larger cage was used to test the monkey’s degree of exploration
What were the findings of Harlow’s study?
Monkeys preferred contact with the towelling mother when given a choice of surrogate mother, regardless of whether she produced milk ( monkeys even stretched across to the wire mother to feed while clinging onto the towelling mother)
Monkeys with only a wire mother had diarrhoea (a sign of stress)
When frightened by a loud noise monkeys clung to the towelling mother in conditions where she was available
In the larger cage conditions, monkeys with towelling mothers explored more and visited their surrogate mother more often.
What conclusions can be drawn from Harlow’s study?
Rhesus monkeys have an innate, unlearned need for comfort , suggesting that attachment concerns emotional security more than food. Contact comfort in associated with lower levels of stress and a willingness to explore indicating emotional security
What is the evaluation of Harlow’s study?
The study involved animals and therefore we cannot necessarily extrapolate/generalise the results to humans
There are ethical issues involving the separation of baby monkeys and causing stress to them
Over time, Harlow publically distanced himself from the work of Bowlby and Ainsworth as well as Lorenz’s views on imprinting. He especially did not believe that his work supported Bowlby’s belief of a child’s innate need for mother love
