In classic research on young monkeys that had been socially isolated, what did Suomi and Harlow (1978) discover?

The work of Suomi and Harlow in 1978 highlighted the importance of social interaction during early phases of development for young monkeys. They found that the first six months of life were especially critical for these animals, as this period laid the foundation for social behavior later on. Monkeys that experienced social isolation during this time showed significantly impaired social skills and difficulties in forming relationships, indicating that early social experiences are pivotal for healthy social development.

This discovery underscores the concept of sensitive or critical periods in development, suggesting that the lack of social interaction during specific timeframes can result in lasting effects that are difficult to reverse. Understanding this critical period sheds light on broader implications for both primate and human development, emphasizing the importance of nurturing environments in the early stages of life.