Ethical Considerations:
* Minimizing harm: Conducting such experiments on human infants would have been ethically unacceptable. The separation and manipulation of infants from their mothers, especially in a way that could cause distress and lasting emotional damage, would be considered cruel and inhumane.
* Informed consent: Young children are incapable of providing informed consent for participation in research.
* Long-term effects: The potential long-term psychological impact of such experiments on human children would be difficult to assess and potentially devastating.
Practical Considerations:
* Control over environment: Monkeys can be raised in controlled laboratory settings, allowing researchers to manipulate variables like the type of surrogate mother, amount of contact, and other environmental factors. This level of control is much more difficult to achieve with human infants.
* Similarities to humans: Monkeys, particularly rhesus macaques, share a significant amount of genetic and physiological similarities with humans. This makes them suitable models for studying social development and attachment behavior.
* Lifespan: Monkeys have a shorter lifespan than humans, allowing researchers to study the effects of early experiences on development more quickly.
It's important to note: While Harlow's research provided valuable insights into attachment theory, the use of animals in research raises important ethical considerations. The ethical implications of animal research continue to be debated, and it's essential to prioritize the welfare of animals involved in any study.