Final answer:
Harlow's studies showed that rhesus monkeys, for normal social and emotional development, require the comfort and contact provided by other monkeys, preferring a soft, cloth surrogate mother over one that provided food but lacked comfort.
Step-by-step explanation:
Harlow's studies demonstrated that for normal social and emotional development, monkeys need contact with other monkeys. In his research, Harlow provided newborn rhesus monkeys with two surrogate mothers – one made of wire that could dispense milk, and another made from a soft, cloth material that did not provide food.
The studies revealed that the monkeys overwhelmingly preferred the comfort provided by the soft, cloth surrogate, despite not receiving nourishment from it. These findings highlighted the importance of social comfort over mere sustenance and showed a parallel to human children's needs for comfort and security in their attachments.