Animal Studies: Lorenz & Harlow

Who was Lorenz and what did he research?

Konrad Lorenz was an ethologist (a zoologist who studies animal behaviour in their natural habitats), who conducted animal studies on the relationships between newborn animals and their mothers - these observations contributed to psychologists understanding of caregiver-infant attachment in humans.

What is imprinting?

Imprinting is much like attachment in human infants, as it bonds a baby animal to its caregiver. It’s where an offspring will follow the first moving object they see once born.

• This phenomenon occurs commonly in birds but also in many mammals and some fishes and insects

What was the procedure of Lorenz’s goslings (1935)?

Lorenz randomly split a clutch of goose eggs into two groups.

• One group was left in their natural habitat with their biological mother (the control group)

• One group was placed in an incubator where the first moving object they saw when they were born was Lorenz (the experimental group)

What were the findings of Lorenz’s goslings (1935)?

• The control group, hatched in the presence of their mother, followed their mother

• The experimental group, hatched in the incubator in the presence of Lorenz, followed Lorenz everywhere

• Even when the goslings were mixed up, the control group continued to follow their mother and the experimental group followed Lorenz

This phenomenon is called imprinting - whereby bird species attach to and follow the first moving object they see.

What was the conclusion of Lorenz’s goslings (1935)?

Lorenz identified a critical period in which imprinting needs to take place; in chicks this critical period can be as brief as a few hours after hatching.

• If imprinting did not occur within that time, Lorenz found that chicks didn’t attach themselves to a mother figure.

What is sexual imprinting?

Lorenz also investigated the relationship between imprinting and adult mate preferences.

• He observed that birds that imprinted on a human would often later display courtship behaviour towards humans.

• In a case study, Lorenz described a peacock that had been reared in the reptile house of a zoo where the first moving object the peacock saw after hatching were giant tortoises, later showed direct courtship behaviour towards giant tortoises.

Lorenz concluded that this meant the peacock had undergone sexual imprinting.

What is a strength of Lorenz’s research?

The existence of support for the concept of imprinting.

• A study by Regolin and Vallortigara (1995) supports Lorenz’s idea of imprinting - Chicks were exposed to one simple shape combination that moved, such as a triangle with a rectangle in front

• A range of shape combinations were moved in front of them and they followed the original most closely

This supports the view that young animals were born with an innate mechanism to imprint on a moving object present in the critical window of development, as predicted by Lorenz.

What is a limitation of Lorenz’s research?

The ability to generalise finding and conclusions from birds to humans.

• The mammalian attachment system is quite different and more complex than that in birds

• For example, in mammals attachment is a two-way street process, so it’s not just the young who become attached to their mothers, but also the mammalian mothers who show an emotional attachment to their young

This means that it is probably not appropriate to generalise Lorenz’s ideas to humans.

Who was Harlow and what did he research?

An American psychologist who studied attachment. He's most well-known for his experiments with rhesus monkeys (1958), which are much more similar to humans than Lorenz’s birds. His experiment focused on maternal-separation, dependency needs and social isolation.

What is the importance of contact comfort?

Harlow observed that newborn monkeys kept alone in a bare cage often died but they usually survived if given something like a cloth to cuddle. This shows that attachment is based more on comfort, security, and affection above all.

What was the procedure of Lorenz’s goslings (1935)?

• Two fake wire ‘mother monkeys’ were created:

  • One plain-wire monkey which dispensed milk

  • One cloth-covered monkey

What were the findings of Lorenz’s goslings (1935)?

• The baby monkeys cuddled the cloth-covered mother in preference to the plain-wire mother

• They also sought comfort from the cloth one when frightened (e.g. by a noisy mechanical teddy bear) regardless of which mother (cloth or wire) dispensed milk

• This suggested that ‘contact comfort’ was of more importance to the monkeys than food when it came to attachment behaviour

What else did Harlow et al. study?

Monkeys who had been deprived of a ‘real’ mother into adulthood, in order to see if the early maternal deprivation had a permanent effect. The researchers found severe consequences.

• The monkeys reared with plain-wire mothers only were the most dysfunctional (impaired)

• However, even those reared with a cloth-covered mother didn’t develop typical social behaviour - they were more aggressive and less sociable than other monkeys and bred less often, being unskilled at mating

• If they became mothers, some of them neglected their young and other attacked their young, even killing them in some cases

What was the conclusion of Harlow’s study?

Like Lorenz, Harlow concluded that there was a critical period for attachment formation - a ‘mother’ figure had to be introduced to a young monkey within 90 days for an attachment to form.

• After this time, attachment was impossible and the damage done by early deprivation was irreversible

What is a strength of Harlow’s research?

It has important real-world application.

• For example, it has helped social workers and clinical psychologists understand that adult difficulties (such as depression and difficulty parenting) may be rooted in poor early bonding experiences (White et al, 2023)

• Harlow’s research has also been applied to improving the welfare of infant primates in zoos (Schapiro and Hau, 2023)

Therefore, the value of Harlow’s research is not just theoretical but also practical.

What is a limitation of Harlow’s research?

It’s ability to generalise its findings and conclusions from monkeys to humans.

• Rhesus monkeys are much more similar to humans that Harlow’s birds, and all mammals share some common behaviours

• However, the human brain and human behaviour is still more complex than that of monkeys

This means that it may not be appropriate to generalise Harlow’s findings to humans.