3.2.2 Lorenz & Harlow

Harlow and the Monkeys (1959)

🎯Aim:

To test the learning theory of attachment by investigating whether monkeys choose comfort or food

Procedure:

Conducted a laboratory experiment where he separated 8 baby monkeys from their real mothers and raised them in a laboratory with a surrogate wire mother and a surrogate towel mother

• For 4 monkeys, the wire mother provided milk
• For the other 4 monkeys, the towel mother provided milk

Findings:

The monkeys always chose the comforting towel mother, over the wire mother, even when the wire mother provided milk

• Therefore, Harlow's study does not support the learning theory of attachment, which suggests attachments are driven by food. Instead, his study suggests that attachments are driven by comfort.

Evaluation of Harlow's study - testing the learning theory:

P: Well controlled, because it was a laboratory experiment

E: Could control extraneous variables which could have influenced the baby monkeys' development

E: This is a strength because it meant that Harlow could establish a cause-and-effect relationship between his independent and dependent variables.

P: The two types of fake mothers had different appearances

E: This could act as a confounding variable

E: Affecting the validity of the findings

P: The study was conducted on monkeys and not human babies

E: This means that the results might not tell us much about how humans form attachments

E: Therefore, the results of Harlow's study might lack generalisability

P: Harlow separated baby monkeys from their mothers and raised them in social isolation

E: Since monkeys can't talk, they couldn't give informed consent to take part in the study.

E: As a result, the monkeys were put in a distressing situation which might have caused emotional distress or psychological harm, meaning the study could be considered unethical.

Lorenz - Imprinting in goslings

Imprinting = Forming an attachment to the first large moving object a younger meets. Occurs for survival and protection

• Lorenz observed imprinting whereby bird species that are mobile from birth attach and follow the first moving object they see.

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• Randomly divided a clutch of geese. Half were hatched with the mother goose while the other half were in an incubator where the first moving object was Lorenz. Mixed them together to see who they would follow

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• Found that the incubator geese followed Lorenz and the control followed the mother.
• Found a 'critical' period in which imprinting needs to take place - usually within first few hours or it does not take place.

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• Sexual imprinting occurs when birds require a template of desirable characteristics required in a mate. E.g a peacock who was born around a turtle was trying to mate/ display courtship towards them.

A limitation is the lack of generalisability. The mammalian attach system is different from birds as mammals show more emotion. Also, mammals can form attachments at different times of their lives. Suggests low ecological validity as it can't be generalised outside of research settings.

A strength is supporting research from Guiton et al who found geese imprinted on yellow gloves would try and mate with them as adults. Suggests young are born with innate mechanisms to imprint on moving objects present during the critical period.

Another limitation is the concept of sexual imprinting isn't that permanent. Guiton et al demonstrated that chickens who imprinted on a glove eventually learnt to to prefer mating with their own kind despite their initial imprinting. Suggests learning and experience are more important factors than imprinting.