Please excuse the Korean subtitles. Original video from http://history.com. Used Febuary 19, 2014. (video excerpt)
A Secret Club
It all began when an informal club was formed. A group of girls, ranging from nine to twenty five, would visit a black slave named Tituba. With her turban, in the kitchen of Mr. Parris, Tituba would tell stories of magic and witchcraft. These visits were highly forbidden. When the youngest of girls began to act strange, the rest of the group fell into hysteria. To cover the secret of their disobedience, the girls began blaming vulnerable people in the village, claiming their spirits were attacking them.
No one really knows how the girls fell into the hysteria--some say it was from Indian attacks, others say it was from the harsh weather, craving for attention, or even possibly smallpox. Some also believe it was an act to cover their misdoings up after the youngest, Elizabeth Parris, had the first attack of hysteria.