Animal studies of attachment - Lorenz and Harlow

Key study - Lorenz (1935) imprinting

• Imprinting - a phenomenon observed in the natural world that describes the process by which young animals follow and form an attachment to the first large moving object they meet - it is mainly exhibited by birds

• 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 develop

• Imprinting provides animals with information about who they are, how they will behave, and who they will find attractive when they reach adulthood.

• Imprinting is irreversible, meaning once formed it cannot be changed.

• Imprinting is an adaptive mechanism, as it ensures the young stay close to a caregiver for protection and survival.

• ALTRICIAL animals = animals that are born undeveloped and need constant care (e.g. humans).

• PRECOCIAL animals  = animals that walk as soon as born (geese, giraffes)

Imprinting – a form of attachment where offspring follow the first large moving object

Critical Period – a specific time period within which an attachment must form

Sensitive Period – a best time period within which attachments can form, though they still can form with more difficulty outside this period

• Filial imprinting - social attachments form between parents and offspring
  Sexual imprinting - attachment forms by which an individual learns to direct it sexual behaviour at members of its own species

lorenz study itself

📌 Overview

• Konrad Lorenz (1935) studied imprinting in birds

• wanted to investigate the mechanism of imprinting

• Imprinting is a form of attachment where young animals follow the first moving object they see

👉 A* key term:
Imprinting is rapid, innate, and occurs during a critical period

🧪 Aim

• To investigate how attachment forms in animals

• To determine whether attachment is innate (biological)

🧪 Procedure

• Lorenz used greylag goose eggs

• Eggs were divided into two groups:

🥚 Group 1 (Control)

• Hatched naturally with the mother goose

🥚 Group 2 (Experimental)

• Hatched in an incubator

• First moving object seen = Lorenz himself

👀 Observations

• After hatching:

  • Control group → followed Mother Goose

  • Experimental group → followed Lorenz

👉 This behaviour is called imprinting

🔄 Cross-Fostering

• Lorenz placed both groups together

• Each group continued to follow:

  • Their imprinted figure (mother or Lorenz)

👉 Shows attachment is not reversible

⏰ Critical Period

• Imprinting must occur within a specific time frame (~12–32 hours after hatching)

👉 If missed:

Imprinting does not occur properly

❤ Long-Term Effects

• Imprinting affects later behaviour

Sexual Imprinting

• Birds later tried to mate with the species they had imprinted on

👉 Example:

Geese imprinted on Lorenz showed courtship behaviour towards humans

🧠 Conclusions

• Attachment is:

  • Innate (biologically programmed)

  • Occurs during a critical period

  • Leads to long-term behavioural consequences

👉 A* key phrase:
Imprinting is an adaptive mechanism that increases chances of survival by ensuring proximity to a caregiver

• Imprinting = fixed action pattern (FAP)

• Triggered by a sign stimulus (first moving object)

• Ensures survival → staying close to caregiver

Procedure, conclusions and findings:

• Lorenz split a clutch of greylag goose eggs; left half with mother to incubate and raise; they showed normal behaviour, followed her, grew up to interact and mate with members of their own species

• The other half of the clutch was placed in an incubator, and Lorenz offered himself as a model for imprinting.

• goslings followed him as if he were their parent; failed to recognise their biological mother or other members of their own species; as adults, tended to develop social relationships with humans, not geese; some attempted to mate with humans

conclusion:

The ability or tendency to respond to the first object seen after hatching is “innate.”

The process of imprinting is genetically determined, but a bird learns to respond to a particular animal or object

⭐ Evaluation of Lorenz’s Animal Study

🔴 1. Generalisability to Humans (DETAILED PEEL)

Point:
A major limitation of Lorenz’s study is that findings from animals may not generalise to humans.

Evidence:
Lorenz’s research was conducted on goslings, whose attachment behaviour is based on imprinting, a fixed and instinctive process.

Explain:
In contrast, human attachment is far more complex and influenced by higher cognitive processes, emotional development, and social interactions. For example, humans form attachments over a longer period and are influenced by learning and environment, not just instinct.

Link:
Therefore, while Lorenz’s findings may demonstrate that attachment has a biological basis, they cannot fully explain human attachment, limiting their overall applicability

🔴 4. Low Ecological Validity (DETAILED PEEL)

Point:
A limitation of Lorenz’s study is that it lacks ecological validity.

Evidence:
The goslings were hatched in an artificial environment (incubators) and exposed to controlled conditions rather than their natural habitat.

Explain:
This may have influenced their behaviour, as imprinting in the wild would involve natural environmental cues and interactions. As a result, the behaviour observed may not fully represent how imprinting occurs in real-life settings.

Link:
Therefore, the findings may not reflect natural attachment behaviour, reducing the external validity of the study

🔴 5. Ethical Issues (DETAILED PEEL)

Point:
Lorenz’s study raises ethical concerns regarding the use of animals in research.

Evidence:
The goslings were deliberately made to imprint on Lorenz instead of their biological mother, leading to long-term behavioural consequences, such as inappropriate mating behaviour.

Explain:
This suggests the animals may have experienced developmental disruption, raising concerns about whether it is acceptable to cause potential harm to animals for human knowledge.

Link:
Therefore, the study may be considered ethically questionable, as it prioritises scientific understanding over animal welfare.

🟢 3. Practical Applications (DETAILED PEEL)

Point:
A key strength of Lorenz’s research is that it has important practical applications.

Evidence:
The study highlights the existence of a critical period for attachment formation.

Explain:
This has influenced the understanding of human attachment by suggesting that early relationships are crucial for later development. It has informed practices such as ensuring infants form bonds with a primary attachment figure, particularly in situations like adoption or childcare, where early bonding may be disrupted.

Link:
Therefore, Lorenz’s findings have real-world value, as they contribute to improving child development and attachment outcomes.

🟢 2. High Internal Validity (Control & Reliability) (DETAILED PEEL)

Point:
A strength of Lorenz’s study is that it was conducted under highly controlled conditions, increasing internal validity.

Evidence:
Lorenz carefully controlled the first moving object the goslings encountered by using an incubator and ensuring they imprinted either on their biological mother or on himself.

Explain:
This level of control meant that extraneous variables were minimised, and the cause of imprinting could be clearly identified. Additionally, the procedure could be replicated, increasing the reliability of the findings.

Link:
Therefore, the study provides strong evidence that imprinting is an innate and biologically driven process, supporting evolutionary explanations of attachment.

🐒 Animal Studies of Attachment – Harlow (1958)

📌 Overview

• Harry Harlow (1958) studied attachment and bonding in rhesus monkeys

• Investigated whether attachment is based on:

  • Food (cupboard love theory)

  • Or comfort (contact comfort)

  • wanted to study the mechanisms by which newborn rhesus monkeys bond to their mothers - these infants were highly dependent on their mothers for nutrition, protection, comfort, and socialisation

👉 A* key idea:
Attachment is formed through emotional security rather than feeding

Harlow’s actual study

🧪 Aim

• To test whether infants attach to caregivers due to:

  • Feeding (learning theory)

  • Or contact comfort (emotional care)

🧪 Procedure

• Harlow separated infant rhesus monkeys from their biological mothers

• Each monkey was placed in a cage with two surrogate mothers:

🍼 Wire Mother

• Made of wire

• Provided milk (food)

🧸 Cloth Mother

• Covered in soft cloth

• Provided no food

👀 Observations

• Monkeys spent:

  • Most time with cloth mother

  • Only visited wire mother for feeding

👉 Indicates preference for comfort over food

😨 Fear Response

• When frightened (e.g. loud noise):

  • Monkeys ran to cloth mother for comfort

👉 Shows attachment figure provides emotional security (safe base)#

🧪 Additional Condition (Control)

• Some monkeys had:

  • Cloth mother who provided food

  • Wire mother without food

👉 Still preferred cloth mother

📊 Findings

• Contact comfort is more important than feeding in attachment formation

• Monkeys formed a strong attachment to the cloth mother

• Attachment behaviour included:

  • Seeking proximity

  • Using mother as a secure base

🚨 Long-Term Effects (Maternal Deprivation)

Monkeys raised without a real mother showed:

• Social abnormalities

  • Aggression

  • Difficulty interacting with others

• Emotional abnormalities

  • Fearfulness

  • Stress

• Reproductive issues

  • Poor parenting skills

  • Neglect or harm to offspring

  • 😨 Stress & Physical Symptoms

    • Monkeys separated from their mothers showed clear signs of distress, including:

      • Diarrhoea

      • Physical stress responses

      • Rocking behaviour (self-soothing)

• These symptoms show that:

  • Attachment is not just emotional

  • It has physical and biological effects

  👉 Lack of attachment = serious developmental harm

🧠 Conclusions

• Attachment is based on contact comfort, not feeding

• Supports idea that attachment is emotional, not learned through reinforcement

👉 Challenges Learning Theory of Attachment

🔗 Link to Human Attachment (A*)

• Supports:

  • Bowlby’s theory (attachment is innate)

  • Importance of secure base

• Suggests early relationships are crucial for:

  • Social development

  • Emotional wellbeing

🧠 A* FINAL CONCLUSION (EXAM GOLD)

Harlow’s study demonstrates that attachment is driven by a need for comfort, security, and emotional support, rather than simply food.

The findings highlight the importance of early attachment relationships, as deprivation can lead to long-term social, emotional, and behavioural difficulties.

This suggests that attachment is a biologically driven and essential process, crucial for normal development.

AO3 evaluations for Harlow’s study

🟢 1. High Internal Validity (Controlled Environment) (DETAILED PEEL)

Point:
A strength of Harlow’s study is that it was conducted in a highly controlled environment, increasing internal validity.

Evidence:
Harlow carefully controlled variables such as the type of surrogate mother (wire vs cloth) and the conditions the monkeys were raised in.

Explain:
This meant that the effects of contact comfort on attachment could be clearly isolated, as other variables were minimised. The consistent conditions also allowed for replication, increasing the reliability of the findings.

Link:
Therefore, the study provides strong, scientifically credible evidence that attachment is driven by emotional comfort rather than food, supporting its validity.

🟢 2. Practical Applications (DETAILED PEEL)

Point:
A major strength of Harlow’s research is its significant practical applications.

Evidence:
The findings showed that early attachment and contact comfort are crucial for healthy development.

Explain:
This has influenced childcare practices, such as improving conditions in orphanages and hospitals, ensuring that infants receive consistent emotional care rather than just physical care. It has also shaped policies around adoption and early bonding, emphasising the importance of forming attachments within a critical period.

Link:
Therefore, Harlow’s research has clear real-world value, as it has helped improve human attachment relationships and developmental outcomes.

🔴 3. Low Ecological Validity (DETAILED PEEL)

Point:
A limitation of Harlow’s study is that it lacks ecological validity.

Evidence:
The monkeys were raised in artificial laboratory conditions with surrogate mothers made of wire and cloth.

Explain:
These conditions do not reflect the complexity of natural environments, where infants interact with real caregivers and social groups. As a result, the behaviours observed may not fully represent how attachment develops in real-life settings.

Link:
Therefore, the findings may lack external validity, as they may not accurately generalise to natural attachment behaviour.

🔴 4. Ethical Issues (DETAILED PEEL)

Point:
A significant limitation of Harlow’s study is that it raises serious ethical concerns.

Evidence:
The monkeys were deliberately separated from their mothers and experienced maternal deprivation, leading to long-term emotional and social damage, including abnormal behaviour and distress.

Explain:
This suggests that the animals suffered psychological harm, raising questions about whether it is acceptable to cause such suffering for research purposes, particularly when the benefits are primarily for human understanding.

Link:
Therefore, the study may be considered ethically unacceptable, which limits its acceptability despite its contributions to knowledge