F. Harlow’s classic experiment with rhesus monkeys dealing with the importance of early contact with the mother.

 

https://www.youtube.com/watch?v=_O60TYAIgC4&list=FL1KN0aFeG7UgUXRaN43Vztg&index=3&fbclid=IwAR0ahu1I4PybeE1plNuZkWTrzu6NAwnqgBfZajxVrv2XqmbR-Hu06xFVf8E