Harlow’s monkey experiments showed that isolation in early months led to behaviors resembling:

• A. Major depressive symptoms
• B. ADHD-like hyperactivity
• C. Aggressive violence
• D. Autistic

Answer: (D)

Early social deprivation during development disrupts how primates learn to interact and regulate emotions. In Harlow’s isolation experiments, infant rhesus monkeys raised without peers showed marked social withdrawal, repetitive or self-stimulatory behaviors, and a profound lack of interest in other monkeys. These patterns resemble autism-like social impairment in humans, such as reduced social interaction and communication and the presence of restricted, repetitive behaviors. The key takeaway is that isolation affects social development in ways that align with autistic-like traits, not primarily with depressive symptoms, hyperactivity, or aggression.