Animal Studies of Attachment Flashcards
Animal studies of attachment: Lorenz and Harlow.
Outline Lorenz’s research into animal attachment
Aim: To investigate the effects of imprinting and how this affects attachment behaviour in geese.
Method: Observation
Procedure: 12 gosling eggs randomly divided in two groups.
When one group their natural mother was the first living/moving thing they saw.
When incubator group hatched Lorenz was the first living thing they saw.
The two groups were mixed up and Lorenz observed who / what they followed.
He varied the time between birth and seeing a moving object so he could measure the critical period for imprinting.
Results: The geese imprinted on the first thing they saw.
The group who first saw Lorenz showed no recognition of their natural mother and continued to follow him.
Conclusion: Lorenz called this phenomenon imprinting; where birdlike species attach to and follow the first moving object / thing they see.
Identified a critical period (first few hours after hatching for birds)) in which imprinting needs to take place. This period depends on the species.
If imprinting does not occur within the critical period, the chicks will not attach to a mother figure.
Outline Lorenz’s case study into animal attachment
The relationship between imprinting and adult mate preferences.
Observed that birds that imprinted on a human –> would often later display courtship behaviour towards humans.
In a case study, a peacock had been reared in the reptile house of a zoo and first saw giant tortoises (first moving objects)
As an adult, this bird would direct courtship behaviour towards giant tortoises.
Lorenz concluded that this meant he had undergone sexual imprinting.
Outline Harlow’s research into animal attachment
Aim: To investigate the factors which influence the development of attachment in monkeys.
Procedure: Harlow took newborn rhesus monkeys from their biological mothers and placed them in a cage.
The cage contained two surrogate mothers:
- One mother was covered in cloth and provided no milk.
- The other mother was made of plain wire and provided milk.
Harlow observed how much time the monkeys spend with each mother.
Results: The monkeys spent 18 hours per day with the cloth covered mother, but just one hour per day with the wired mother.
Conclusion: Harlow concluded that contact comfort is more important than food (milk) in attachment behaviour.
What were the long-lasting effects of Lorenz’s research?
Sexual imprinting: There is a relationship between imprinting and adult mate preferences.
Critical period: If imprinting does not occur in the first few hours after hatching, the chicks will not attach themselves to a mother figure.
What were the long-lasting effects of Harlow’s research?
Followed the monkeys who had been deprived of a ‘real’ mother into adulthood to see if it had a permanent effect.
The monkeys reared with only wire mothers were the most dysfunctional, however even those reared with a soft toy as a substitute did not develop normal social behaviour –> more aggressive and less sociable and bred less often than monkeys typically do - more unskilled at mating
Some neglected their young and others attacked their children, even killing them in some cases
Outline a strength of Lorenz’s research
Research support for imprinting
P: Numerous other studies have demonstrated imprinting in animals.
Ev: Guiton demonstrated that leghorn chicks became imprinted on yellow rubber gloves when exposed to them while being fed during their first few weeks.
The male chickens later tried to mate with gloves (sexual imprinting - an example of one of the long lasting effects of imprinting), showing that early imprinting is linked to later reproductive behaviour.
Ex: Young animals are not born with a predisposition to imprint on a specific type of object but probably to any moving thing that is present during the critical period.
L: Support the findings and conclusions made by Lorenz in his original study of goslings.
CA: Later researchers have questioned some of Lorenz’s conclusions. Guiton found chickens eventually learned to prefer mating with other chickens = impact of imprinting on mating behaviour is not as permanent as Lorenz believed.
Outline a limitation of Lorenz’s research
Criticisms of imprinting
P: There is some dispute over the characteristics of imprinting.
Ev: For many years, imprinting was considered irreversible. It is now understood that imprinting is more a ‘plastic and forgiving mechanism’, according to Hoffman.
Guiton found that he could reverse the imprinting in chickens that had initially tried to mate with the rubber gloves. He found that later, after spending time with their own species, they were able to engage in normal sexual behaviour with other chickens.
Ex: Suggests imprinting is reversible and species can go on to engage in normal sexual behaviours if they spend time with their own species.
L: Therefore, it could be argued that the effects of imprinting are not long-lasting as once thought.
Outline a strength of Harlow’s research
Practical application
P: Practical value to real life.
Ev: In hospitals skin to skin contact is practiced where a baby is dried and laid directly on the mother’s bare chest after birth, both of them covered in a warm blanket and left for at least an hour or until after the first feed.
Ex: Supports Harlow’s research as he suggested that contact comfort is more important in developing an attachment with mother and infant as opposed to food.
L: Harlow’s research has provided us with credible insight into the importance of contact comfort and forming an attachment to ensure children develop typically.
Outline two limitations of Harlow’s research
Confounding variable
P: Harlow’s research lacks control of important variables.
Ev: Face of surrogate mother covered in cloth looked like a monkey, whereas the wired surrogate mother looked more robotic.
Ex: Perhaps the monkey spent more time with the cloth surrogate mother because its face looked similar to its own, i.e. more like its actual mother would look than the wired mother.
L: Study lacks internal validity so perhaps we should replicate the study where both the wired mother and the cloth mother have the same face so we can be certain of Harlow’s findings in relation to contact comfort.
Ethical Issues
P: Research into animal behaviour, specifically attachments, has been criticised for being unethical.
Ev: Harlow purposefully frightened the monkeys using a mechanism to which the monkey was screaming and ran to hold its cloth surrogate mother.
Ex: Unethical because it may have caused the monkeys psychological harm which strips them of their dignity. Moreover Harlow also, therefore, breached the ethical guidelines.
CA: Harlow’s study may have been necessary in order to find out if contact comfort is more important than food.
