animal studies

• Lorenz procedure

  he set up an experiment in which he randomly divided a group of goose eggs. half the eggs were hatched with the mother in their natural environment. the other half hatched in an incubator where the first moving object they saw was Lorenz
• Lorenz findings

  the incubator group followed Lorenz everywhere whereas the control group followed the mother. When the two groups were mixed up the control group continued to follow the mother and the experimental group followed Lorenz
• Lorenz findings continued

  this is called imprinting where bird species from birth attach to and follow the first moving object they see. Lorenz identified a critical period in which imprinting needs to take place. Depending on the species this can occur in a few hours after hatching. If imprinting does not occur within that time Lorenz found that chicks did not attach themselves to a mother figure
• sexual imprinting

  Lorenz also investigated the relationship between imprinting and adult male preferences. He observed that birds that imprinted on a human would later display courtship behaviour towards humans. He described a peacock in a reptile house saw the first moving object of a giant tortoise. They behaviour was then directed only towards the giant tortoise. He concluded that this meant he had undergone sexual imprinting
• A03 Lorenz - generalisability to humans

  • his research was done on imprinting in birds therefore there is a problem in generalising from findings on birds to humans
• A03 Lorenz - observations have been questioned

  • Guiton found that chickens imprinted on yellow washing up gloves and would try to mate with them as adults but that with experience they eventually learned to prefer mating with other chickens
  • this suggests the impact of imprinting on mating behaviour is not as permanent as Lorenz believed
• Harlow's 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 whereas in a second condition the milk was dispensed by the cloth-covered mother
• Harlow's findings

  It was found that baby monkeys cuddled the soft object in preference to the wire one and found comfort from the cloth when frightened regardless of which dispensed milk. this showed that contact comfort was of more importance than the food when it came to attachment behaviour
• Maternally deprived monkeys as adults

  Harlow also followed the monkeys who had been deprived of a real mother into adulthood to see if early maternal deprivation had a permanent effect. the monkeys with wire mothers only were the most dysfunctional but the soft toy also did not develop normal social behaviour. they were more aggressive and less sociable and they bred less often. some of the deprived mothers attacked and killed their children
• the critical period for normal development

  Harlow concluded that there was a critical period for this behaviour. a mother figure had to be introduced to a monkey within 90 days for an attachment to form. after this time attachment was impossible and the damage from early deprivation became irreversible.
• A03 Harlow - theoretical value

  • his findings have a good effect on understanding of human mother-infant attachment
  • he showed that attachment does not develop as a result of being fed by a mother figure but as a result of comfort contact
  • showed the importance of early relationships for later social development
• A03 Harlow - practical value

  • it has helped social workers understand the risk factors in child neglect and abuse and how to prevent it
  • importance of proper attachment figures in zoos and also in breeding programmes
• A03 Harlow - ethical issues

  • the monkeys suffered as a result of the procedure
  • this species is considered similar enough to humans to be able to generalise the findings which means the suffering is quite likely to be the same for humans