
Developmental psychologists in the 1940s - 1950s believed that infants became attached to those who provided them with nourishment - a widely-held theory that ignored the role of physical contact.
Harry Harlow took gave orphaned baby monkeys two artificial ‘mothers’ - one was wire and provided milk, the other was covered in soft cloth but provided no milk.
Harlow concluded that the stimulation/reassurance from the physical touch of a parent plays a key role in developing healthy physical growth and normal socialisation.
