Animal Research

• • animal studies look at the early bonds between non-human parents and their offspring
  • can help us understand attachment in humans
• imprinting

  • form of learning where a young animal fixes on the first object that moves
  • this happens within the first dew hours of birth, if it does, then it won't happen at all
  • there is a critical period for the imprinting
• Lorenz (1935) - procedure

  • took a clutch of gosling eggs and dividing them into two groups
  • one group was hatched with their natural mother and the others were hatched in an incubator
  • when the incubator eggs hatched the first living thing that they saw moving was Lorenz and soon started following him around
  • Lorenz marked the two groups to distinguish them and placed them together
  • both Lorenz and the natural mother were present
• Lorenz (1935) - findings

  • the goslings divided themselves, one following the natural mother and the other following Lorenz
  • Lorenz's brood showed no recognition of their natural mother
  • noticed that this process of imprinting is restricted to a very indefinite period of the animal's life
  • if an animal is not exposed to a moving object during this period they will not imprint
  • imprinting to humans did not occur in some animals, for example, curlews will not imprint on a human
• long lasting effects of imprinting

  • the process is irreversible and long lasting
  • has a later effect on mate preferences and animals will choose a mate with the same kind of object of which they were imprinted
• evaluation

  • lots of replication, all coming to similar conclusions with other species of birds
  • young animals are not born with a predisposition to imprint to a certain type of object but actually imprint to any moving object within the critical period
  • supports Lorenz's predictions that animals are born with an innate mechanism to imprint on a moving object in a critical period
  • has both external and internal validity
  • birds can't be generalised to humans
  • the mammalian attachment system is very different to the birds
• Harlow (1959) - procedure

  • created 2 mothers each with a different head and one was wrapped in soft cloth
  • 8 infant rhesus monkeys were studied for 165 days
  • for 4 monkeys the milk bottle was on the cloth-covered mother and on the plain wire mother for the 4 others
  • measurements were made of the amount of time each infant spent with the different mothers
  • observations were also made of the monkey's responses when frightened
• Harlow (1959) - findings

  • all 8 monkeys spent most of their time with the cloth covered mothers
  • those monkeys who fed from the wire mother only spent a short amount of time getting milk and then returned to the cloth-covered mother
  • when frightened, all monkeys clung to the cloth-covered mother
  • when playing with new objects the monkeys often kept one foot on the cloth covered mother for reassurance
  • these findings suggest that infants do not develop an attachment to the person who feeds them but to the person who offers contact
• long lasting effects - Harlow

  • motherless monkeys, even those who had contact comfort, developed abnormally
  • socially abnormal - froze or fled when approached by other monkeys
  • sexually abnormal - did not show normal mating behaviour and didn't cradle their own babies
  • there is also a critical period for these effects
  • if motherless monkeys spent time with their peers, they seem to recover but this was only if this happened before 3 months
  • having more than 6 months with only a wire mother was something they didn't appear to recover from