Abigail Williams and Ann Putnam seek Tituba's knowledge of conjuring for their personal wants and desires.
We learn from Betty, Abigail's cousin, that when they were in the forest, Abigail “drank a charm to kill John Proctor‘s wife! You drank a charm to kill Goody Proctor!” This confession allows us to realize from the beginning of the play how far Abigail is willing to go to get John Proctor. Abigail is not just a young girl with a crush; instead, she's willing to conjure spirits, an act they not only believe in but that they believe to be sinful, in order to take out anyone she sees as competition.
As the act continues, we learn that the Putnams have lost all of their children shortly after they were born. John Putnam explains to the town that he has often wondered if witchcraft may have been the reason for his family's tragedy:
Putnam: How may we blame ourselves? I am one of nine sons; the Putnam seed have peopled this province. And yet I have but one child left of eight—and now she shrivels!
The citizens of Salem have limited medical knowledge, so the Putnams, like many people of the time, believe that evil forces are to blame for their misfortunes. Goody Ann admits that she sent her only remaining daughter to Tituba to find out why the other children died and to ensure that her health is fine.
Ann: I know it, sir. I sent my child… she should learn from Tituba who murdered her sisters.
While both Ann and Abigail admit to calling about spirits and participating in witchcraft, it is the slave, Tituba, who gets in trouble for breaking the law.