Animal studies of attachment

Lorenz (1935) found that geese automatically 'attach' to the first moving thing they see after hatching, and follow it everywhere. This is called imprinting.

He randomly divided a clutch of greylag goose eggs into two groups. He left one group with the mother and incubated the other eggs. 

Lorenz observed that the goslings from the incubator eggs followed him around in exactly the same way that the goslings from the other egg would follow their mother.

He put both sets of goslings together and observed that when they were released, the two groups quickly re-formed as the goslings went off in search of their respective 'mothers'. Both sets of gloslings had imprinted on the first moving object that they'd seen.

After further experiments, Lorenz determined that imprinting was most likely between 13 and 16 hours after hatching.

As such, he concluded that imprinting seems to occur during a 'critical period' It's a fast, automatic process.

He also noted that after this critical period, it was too late for the young birds ever to imprint.

it's unlikely to occur in humans. Our attachments take longer to developand we don't automatically attach to particular things - quality care seems more important in human attachment formation. However, Bowlby's theory is based on the same principles.

Method:

• Aimed to find out whether baby monkeys would prefer a source of food or a source of comfort and protection as an attachment figure.
• In lad experiments rhesus monkeys were raised in isolation.
• They had two 'surrogate' mothers, one made of wire with a feeding bottle and one made with cloth but no bottle.

Results:

• Monkeys spent most of their time clinging to the cloth surrogate and only used the wire surrogate to feed. 
• Cloth surrogate seemed to give them comfort in new situations.
• Monkeys grew up to be socially and emotionally disturbed.
• Females grew to be bad mothers and were often violent towards their offspring.

Conclusion:

• Infant monkeys formed more of an attachment with a figure that provided comfort and protection. Growing up in isolation affected their development.

Evaluation:

• Lab experiment - strict control of variables.
• Can't generalise results to humans - humans and monkeys are qualatively different.
• Ethical problems - monkeys were stressed and showed signs of being psychological damage.
• Unfair to keep them in isolation - lacks ecological validity.
• Experiment can be replicated but ethical guidelines now prohibit this.

Harlow's (1959) study concluded that rhesus monkeys developed stronger attachments with a cloth surrogate than a wire surrogate. He carried out further studies with different conditions.

Harlow and Zimmerman (1959) added a fearful stimulus.

• Fearful stimulus placed in the cage, monkey would cling to the cloth surrogate first before exploring the object.
• Monkeys in cages with only a wire surrogate would remain frozen or run wildly.
• Researchers concluded that a strong attachment with a primary caregiver is therefore highly important in the development to that of an infant.

Harlow and Sumoi (1970) investigated other factors in generating a strong attachment.

• Placed a cloth surrogate with food and a loth surrogate without food in the cage, they found that the one with food was preferred.
• Concluded that food may still be a significant factor in developing attachments.

When animals are used in research, the findings of the studies should be interpreted carefully. It's hard to generalise the findings from one species to another because the behaviour of an animal can often be very different to that of a human.

Lorenz used a precocial species - species that have their eyes open and can walk right from birth. So they're very different from human infants.

Although the results of animal studies might not always be generaliable to human populations, they can often influence policies and theories in different areas of research.

Although animal studies have provided valuable information for developmental research, there's debate about whether they're ethical or not.

Advantage - Some research designs couldn't have been conducted on humans ethically.

Disadvantage- Some see it as unethical to inflict suffering on animals, especially when they can't give consent.