A good sample case study on how isolation affects a child's development is the case of Genie, a child who grew up confined to her room and almost entirely isolated from all human contact until the age of 13. This period of isolation severely affected her physical and cognitive development.
Genie's father misunderstood a diagnosis of mild developmental delay when she was 14 months old and from then onward confined her entirely in her room with minimal human contact. For the next 12 years, she had no contact with her mother or brother, and her father beat her or barked at her if she made any sound. Genie escaped at the age of 13 when her mother ran away from the house and took her along. At that time, the child could not stand straight, knew only about 20 words, was not toilet trained and constantly salivated.
After a few months of therapy, she learned to dress herself and provide one-word answers. However, she made very little progress with regard to vocabulary and the ability to ask questions. As she grew older, she learned to communicate through sign language and practiced basic communication skills with those with whom she was most familiar. Despite receiving custody, Genie's mother found it too difficult to care for her and released her into foster care. As of 2008, Genie had been through six foster homes, remaining much below normal in terms of emotional and cognitive development.