Animal Studies of Attachment: Lorenz and Harlow

Click here for a key exam tip linked to AO1 description!! 

Animal Studies of Attachment: Lorenz, Imprinting and the Greylag Geese (AO1, Description):

Click here for a key exam tip – how to effectively outline a study!!          Lorenz's Study

Aim: To investigate the mechanisms of imprinting where the youngsters follow and form an attachment to the first large, moving object that they meet.


  • Lorenz (1935) split a large clutch of greylag goose eggs into two batches. One batch hatch naturally with the mother, the other batch hatched in an incubator with Lorenz making sure that he was the first moving object the goslings encountered.
  • The gosling’s behaviour was recorded.
  • Lorenz marked the goslings so that he knew whether they had hatched naturally or whether they had hatched in the incubator.
  • He placed all the goslings under and upturned box. The box was then removed and the gosling’s behaviour was recorded.


  • After birth, the naturally hatched baby goslings followed their mother about whilst the incubator hatched goslings followed Lorenz around.
  • When released from the upturned box, the naturally hatched goslings went straight to their mother whereas the incubator hatched goslings went straight to Lorenz (showing no bond to their natural mother).
  • These bonds proved to be irreversible (the naturally hatched goslings would only follow their mother; the incubator hatched goslings would only follow Lorenz).
  • Lorenz noticed how the process of imprinting occurred only a short period of time after birth (between 4 and 25 hours).

Conclusion: Imprinting is a form of attachment, exhibited mainly by                                   nidifugous birds (ones who have to leave the nest early), whereby close contact is kept with the first large moving object encountered.

Evaluation of Lorenz’s Animal Study (AO3):

Click here for a key exam tip – how to effectively evaluate!!


(1) POINT: A strength of Lorenz’s study is that its findings have been highly influential within the field of developmental psychology. EXAMPLE: For example, the fact that imprinting is seen to be irreversible (as suggested in Lorenz’s study) suggests that attachment formation is under biological control and that attachment formation happens within a specific time frame. EVALUATION: This is a strength because it lead developmental psychologists (such as Bowlby) to develop well recognised theories of attachment suggesting the attachment formation takes place during a critical period and is a biological process. Such theories have been highly influential in the way child care is administered today.


(1) POINT: A weakness of Lorenz’s study is that it can be criticised for extrapolation. EXAMPLE: Lorenz conducted his study on imprinting on animals – the greylag geese. EVALUATION: This is a weakness because humans and animals (in this case, greylag geese) are physiological different. The way a human infant develops an attachment with their primary caregiver could be very different to the way a greylag geese forms an attachment with their primary caregiver, therefore the findings cannot be generalised.


(2)POINT: A further weakness of Lorenz’s findings is that later researchers have questioned Lorenz’s conclusions. EXAMPLE: For example, Guiton et al (1966) found that chickens imprinted on yellow washing up gloves would try to mate with them as adults however, with experience, they eventually learned to prefer other chickens. EVALUATION: This is a weakness because this suggests that the impact of imprinting on mating behaviour is not as permanent as Lorenz believed.


Animal Studies of Attachment: Harlow, (AO1, Description):

Aim: To test Learning theory by comparing attachment behaviour in baby monkeys given a wire surrogate mother producing milk with those given a soft towelling mother producing no milk.

Procedure: Two types of surrogate mother were constructed – a harsh wire mother and a soft towelling mother. 16 baby monkeys were used, 4 in each condition.

  • A cage containing a wire mother producing milk and a towelling mother producing no milk.
  • A cage containing a wire mother producing no milk and a towelling mother producing milk.
  • A cage containing a wire mother producing milk
  • A cage containing a towelling mother producing milk.

The amount of time spent with each mother was recorded, as well as feeding time was recorded. The monkeys were also frightened with loud noises to test for mother preference during times of stress.


  • Monkeys preferred contact with the towelling mother when given a choice of surrogate mother (regardless of whether she produced milk).
  • He monkeys even stretched across to the wire monkey to feed whilst still clinging to the towelling mother (providing comfort).
  • Monkeys with only the wire surrogate suffered from diarrhoea (a sign of stress).
  • When frightened by a loud noise monkeys clung to the towelling mother (when this was available).
  • In the larger cage conditions, monkeys with the towelling mothers explored more and visited their surrogate mother more.

Conclusion: Rhesus monkeys have an innate, unlearned need for contact comfort, suggesting that attachment concerns emotional security more than food. Contact comfort is associated with lower levels of stress and a willingness to explore, indicating emotional security.

Evaluation of Harlow’s Animal Study (AO3):


(1) POINT: A strength of Harlow’s study is that it was conducted in a controlled, laboratory setting. EXAMPLE: Harlow was able to control potential extraneous variables such as the monkeys being taken away from their mothers straight after birth, the baby monkeys not being exposed to any love or attention from their biological mothers.EVALUATION: This is a strength because it means that Harlow was measuring what he intended to measure (i.e. factors that can affect the formation of attachment) and therefore, the study can be seen to have high internal validity allowing a cause and effect relationship to be established.


(1) POINT: A weakness of Harlow’s study is that it was conducted in a controlled, artificial laboratory setting. EXAMPLE: the highly controlled laboratory setting that Harlow used is not reflective of the real life situations and may cause the monkeys to behave in an artificial manner. EVALUATION: This is a weakness because it means that Harlow wasn’t necessarily measuring the real-life attachment formation and therefore the study can be criticised for lacking ecological validity.

 (2) POINT: Another weakness of Harlow’s study is that it can be seen to be unethical. FOR EXAMPLE: the monkeys in Harlow’s study showed great distress when they were removed from their biological mothers. In addition, after the study, when the monkeys were placed in situation with other rhesus monkeys (who hadn’t been involved in Harlow’s original research), the rhesus monkeys from the study showed great distress in social situations and were unable to communicate with  other monkeys. In addition, when the monkeys from the study had their own children many were said to neglect their offspring and (in some extreme circumstances) killed their offspring. EVALUATION: This is a weakness because Harlow’s study can be seen to be in breach of the BPS guidelines (it fails to protect the monkeys from harm). Furthermore, this study doesn’t tell us anything about the formation of human attachments (monkeys and humans are physiologically different). Therefore Psychologists would argue that the lack of generalizability from this research makes Harlow’s study even more unethical.

Harlow's Monkeys