Animal Studies

Animal Studies

1. Lorenz's Research

   • Imprinting
     • First observed the phenomenon of imprinting when he was a child and a neighbour gave him a newly hatched duckling that then followed him around
   • Proceedure
     • Set up a classical experiment in which he randomly divided a clutch of goose eggs
     • Half the eggs were hatched with the mother goose in their natural environment
     • The other half hatched in an incubator where the first moving object they saw was Lorenz
   • Findings
     • The incubator group followed Lorenz everywhere
       • The controlled group followed the mother
     • When the two groups were mixed up the control group still followed the mother and the experimental group followed Lorenz
       • imprinting occured
     • Lorenz identified a critical period in which imprinting needs to take place
       • Depending on the species this can be as brief as a few hours after birth
     • If imprinting does not occur within that time Lorenz found that chicks did not attach themselves to a mother figure
   • Sexual Imprinting
     • Investigated the relationship between imprinting and adult mate preferences
     • Observed that birds that imprinted on a human would often later display courtship towards humans
     • In a case study Lorenz described a peacock that had been reared in a zoo where the first moving object it saw after hatching were giant tortoises
       • As an adult this bird would only show courtship towards giant tortoises
     • Concluded that the peacock had undergone sexual imprinting

2. Harlow's Research

   • Importance of contact comfort
     • Observed newborn rhesus monkeys kept alone in a bare cage usually died
     • Rhesus monkeys usually survived if given something soft like cloth to cuddle
   • Procedure
     • Harlow tested the idea that a soft object serves some of the functions of a mother
     • In one experiment he reared 16 baby monkeys with two wire model 'mothers'
     • In one condition milk was dispensed by the plain wire mother,
       • In a second condition the milk was dispensed by the cloth mother
   • Findings
     • Baby monkeys cuddled the soft object in preference to the wire one
     • Sought comfort from the cloth one when frightened
       • Regardless which dispensed milk
     • Showed that 'contact comfort' was of more importance to the monkeys than food
   • Maternally deprived monkeys as adults
     • Monkeys who had been deprived of a 'real' mother (maternal deprivation) into adulthood had a permanent effect
       • Severe consequences
     • The monkeys reared with wire mothers were the most dysfunctional
       • However, even those reared with a soft toy did not develop normal social behaviour
     • Those with the soft toy were more aggressive and less sociable than other monkeys and they bred less often, being unskilled at mating
     • As mothers some of the deprived monkeys neglected their young and others attacked their children
   • Critical Period for Normal Development
     • Harlow concluded a critical period for this behaviour
     • A mother figure had to be introduced to an infant monkey within 90 days for attachment to form
       • After this time attachment was impossible and the damage was done by early deprivation became irreversable

3. Evaluaion

   • Theoretical Value (P)
     • Contributed to psychologists' understanding of human mother-infant attachment
     • Harlow showed that attachment does not develop as the result of being fed by a mother figure
       • But as a result of contact comfort
     • Showed us the importance of quality early relationships for later social development
       • Ability to hold down adult relationships and rear children
   • Practical Value (P)
     • Helped social workers understand risk factors in child neglect and abuse and so intervene to prevent it
     • These findings are also important in care of captive monkeys
       • Importance of proper attachment figures for baby monkeys in zoos
   • Ethical Issues (N)
     • Monkeys suffered greatly
     • The species is considered similar enough to humans to be able to generalise findings
       • Suffering was presumably quite human-like
     • Aware of the suffering he was causing
       • Wire mothers referred to as 'iron maidens' after a medieval torture device
     • However, some argue his research was sufficiently important to justify the effects
   • Generalisability to Humans (N)
     • Issue with generalising birds to humans
     • Mammalian attachment system is quite different from the birds
     • Mammalian mothers show more emotional attachment to young than birds do
       • Mammals may be able to form attachments at any time
     • Not appropriate to generalise any of Lorenz's ideas to humans
   • Some of Lorenz's Observations have been Questioned (N)
     • The idea that imprinting has a permanent effect on mating behaviour
       • Guiton et al found that chickens imprinted on yellow washing up gloves would try to mate with them as adults, but learned to prefer mating with other chickens
     • Suggested the impact of imprinting on mating behaviour is not as permanent as Lorenz beieved