Here's a breakdown:
* The experiments: Harlow separated infant monkeys from their mothers and raised them in isolation. He created two surrogate mothers – one made of wire mesh and one covered in soft terrycloth. The monkeys preferred the cloth mother even though it offered no food or warmth.
* Observed effects: The isolated monkeys exhibited severe emotional and behavioral problems. They were fearful, withdrawn, and unable to interact with other monkeys. They engaged in self-harming behaviors, including rocking, biting, and pulling out their own hair.
* Long-term effects: While the isolated monkeys showed significant improvement after being reintroduced to social groups, they continued to exhibit some social and emotional deficits throughout their lives. For example, they were more likely to be aggressive and less successful at mating.
Key points to consider:
* Permanent damage: It is difficult to definitively conclude that the effects were "permanent" as the monkeys were never studied for their entire lifespan.
* Extrapolation to humans: While the Harlow studies provide valuable insights into the importance of early social interaction, it's important to be cautious about extrapolating the findings directly to humans. Human infants are much more complex and have different developmental trajectories.
* Ethical concerns: The Harlow studies have been criticized for their ethical implications, as they involved the deliberate infliction of distress and deprivation on infant animals.
Conclusion: The Harlow studies provide compelling evidence that early social isolation can have profound and long-lasting negative effects on the development of infant monkeys. However, it's important to acknowledge the limitations of the studies and avoid overstating the conclusions, particularly when applying them to human development.