Animal Studies

• •Imprinting is an innate readiness to develop a strong bond with the mother, which takes place during a specific time in development (often the first few hours after birth/hatching). If it doesn’t happen at this time, it probably won’t happen i.e. there is a critical period. It is irreversible and long-lasting.
• •Sexual imprinting is the idea that imprinting can affect adult mate preferences. Animals will choose to mate with the same kind of object upon which they were imprinted.
• Animal studies on attachment look at the formation of early bonds between non-human parents and their offspring.  This is interesting to psychologists because this attachment-like behaviour is common to a range of species and so animal studies can help us understand attachment in humans.
• Lorenz

  until they were about to hatch out. He randomly divided half of the eggs placed under a goose mother, while Lorenz kept the other half beside himself, in an incubator for several hours.

    When the geese hatched Lorenz imitated a mother duck's quacking sounds, upon which the young birds in the experimental group regarded him as their mother and followed him accordingly. The control group followed the mother goose.
• Lorenz

  Lorenz found that geese follow the first moving object they see, during a 12-17 hours critical period after hatching (if not sooner). This process is known as imprinting, and suggests that attachment is innate and programmed genetically.

    Imprinting has consequences both for short term survival and in the longer term forming internal templates for later relationships. Imprinting occurs without any feeding taking place. If no attachment has developed within 32 hours it’s unlikely any attachment will ever develop.
• Lorenz and sexual imprinting


  Lorenz also investigated the relationship between imprinting and adult mate preferences.•His observations demonstrated that birds which had imprinted on a human would often later display courtship behaviour towards humans.
• Lorenz (1952) identified that a peacock that had been reared in a reptile house of a zoo, had sexually imprinted on a giant tortoise as this was the first moving object the peacock had seen.  As an adult, this peacock would only show courtship behaviour towards giant tortoises.
• Eval LorenzAo3 – supporting evidence

  •Research has found that chickens exposed to yellow rubber gloves for feeding them during the first few weeks became imprinted on the gloves and would try to mate with them as adults.••This supports the idea that young animals imprint on any moving thing that is present during the critical window of development and so suggests that his results have some external validity to other birds.
• Ao3 – generalisability to humans? Lorenz

  •Lorenz was interested in imprinting in birds. Although some of his findings have influenced our understanding of human development, there is a problem in generalising findings on birds to humans.•Human mothers show more emotional attachment to young than birds do.••This means that it may not be appropriate to try to generalise any of Lorenz’s ideas to humans. As such, Lorenz’s study may have low external validity.
• Ao3 – undermining research

  •The same research found that with experience, the chickens eventually learned to prefer mating with other chickens••This suggests that the impact of imprinting on mating behaviour is not as permanent or irreversible as Lorenz believed.
• Harlow

  Harlow wanted to study the mechanisms by which newborn rhesus monkeys bond to their mothers. Harlow observed that baby monkeys usually died if they were left alone in a cage with no comfort.

    Harlow tested the idea that a soft object serves some of the functions of a mother. In his experiment, he reared 16 rhesus monkeys with two wire model ‘mothers’.
• Harlow

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    Both groups of monkeys spent more time with the cloth mother (even if she had no milk). The infant would only go to the wire mother when hungry. Once fed it would return to the cloth mother for most of the day. If a frightening object was placed in the cage the infant took refuge with the cloth mother (its safe base).

    This surrogate was more effective in decreasing the youngsters fear.
• Harlow


  The infant would explore more when the cloth mother was present. This supports the evolutionary theory of attachment, in that it is the sensitive response and security of the caregiver that is important (as apposed to the provision of food).
• Harlow: critical period and maternal deprivation


  H •continued to study the monkeys who had been deprived of a real mother into adulthood to see if this early maternal deprivation had a permanent effect. He reported that the motherless monkeys, even those who did have contact comfort, developed abnormally.
• Harlow: critical period and maternal deprivation


  They were socially abnormal (froze or fled when approached by other monkeys, were more aggressive and less sociable), and sexually abnormal (they did not show normal mating behaviour as they mated less than other monkeys and were unskilled at mating). Some of the deprived monkeys also neglected their young, and others attacked their children, even killing them in some cases.•
• Harlow: critical period and maternal deprivation


  •Like Lorenz, Harlow concluded that there was a critical period for this behaviour – a mother figure had to be introduced to an infant monkey within 90 days for an attachment to form. After this time, attachment was impossible and the damage done became irreversible.
• Ao3 – application to the real world Harlow

  •Harlow’s findings have had a massive impact on psychologists’ understanding of human mother-infant attachment. Harlow showed that attachment doesn’t develop as a result of being fed by a mother figure, but as a result of contact comfort. Harlow also showed us the importance of the quality of early relationships for later social development, including the ability to hold down adult relationships and successfully rear children.••This supports the external validity of Harlow’s conclusions.
• Ao3 – real-world application Harlow


  •Harlow’s research has helped social worked understand risk factors in child neglect and abuse, and so intervene to prevent it. The research is also important for the care of captive monkeys – we now understand the importance of proper attachment figures for baby monkeys in zoos, and in breeding programmes in the wild.
• Ao3 – ethics Harlow


  •The study has been criticised for its ethical issues. The monkeys suffered greatly as a result of the procedures. As the animals are quite similar to humans, the suffering is presumably quite human-like. Harlow himself was aware of the suffering he caused.
• Ao3 – mother’s heads Harlow


  •The two ‘mothers’ differed in other ways, other than being cloth-covered or not. The two heads were very different and so act as a confounding variable.••It is not possible to determine whether the infants preferred the cloth-covered ‘mother’ because it was cloth-covered or because it had a more attractive head. Therefore the results lack internal validity as we can’t determine cause and effect so we can’t be entirely confident in Harlow’s conclusion about the importance of contact comfort.