Abigail Williams is a central figure in the play and perhaps one of the most significant dramatic presences within it. The events of the play often turn on her actions, and her behavior could be said to be a major reason for the escalation of the events in Salem Village that eventually led to the execution of eighteen people. The play is a fictionalization of the actual historical events, and it has been reported in historical documents that Abigail was only 11 years old at the time the trials took place (though she was a servant in the Proctor household), so it is not clear if Abigail was in fact responsible for as much of what happened as The Crucible conveys.
However, in pinpointing the capricious nature of a young servant girl who seeks attention and revenge after being spurned by her employer (who she seduced), the author wisely emphasizes the motivating factors that helped cause this debacle. Of course, Miller creates the context of a sexual and romantic liaison between John Proctor and Abigail to heighten the dramatic tension and also to add complex motivations to the characters' situations: Abigail is motivated by love and lust, as well as a desire to remove Elizabeth as an obstacle; while Proctor is motivated by guilt and shame, as well as anger at Abigail for her lies and manipulation, and a desire to protect Elizabeth.
While it is true that girls in the 17th century married and had children at much younger ages than they tend to in contemporary society, it is still a bit of a stretch for Miller to frame the witch trials as having been caused in part by an illicit affair. But as a dramatic device, it is a powerful and appropriate element that illuminates the play's larger themes. The girls who acted as "officials of the court" were mainly servants with poor prospects for marriage. As servants, many of them would have been mistreated. They certainly were not used to be the center of attention or even being listened to. When it became apparent that the villagers and the magistrates were looking at their behavior and listening to their words, they became intoxicated by the attention and ego-gratification. Who wouldn't want to be treated like comparative royalty instead of doing chores all day?
But more to the point, the alluring nature of the girls' budding sexuality, and their antics in the woods where they danced around a fire (where they also performed acts of folk magic under the direction of Tituba, to "conjure spirits" for innocent reasons, such as trying to find out the names of men they might marry), evoked imagery that obviously stoked the imaginations of the villagers. Adolescent sexuality is a powerful force in culture, and surrounded with taboos as well; and the portrayal of a young woman with sexual agency is often seen as threatening, and the seductive nature of female witches is in fact a major theme in the literature of the witchcraft hysteria in Europe and Colonial America. The Malleus Maleficarum, written in Germany in the 16th century as a guide for hunting witches, states "All witchcraft stems from carnal desire, which is in women insatiable."
The portrayal of Abigail as a seductive, manipulative young woman contrasts with Proctor's righteous anger at her lies and her attempts to implicate his wife. Abigail's lust is therefore the motivation behind a major plot point of the play, which is a very bold, even controversial, dramatic choice, since it echoes the sexist and derogatory nature of the historic witch trials that resulted in many thousands of women being tortured and executed.
By emphasizing the threatening nature of female sexuality, but positioning it alongside the childlike jealousy and vindictiveness Abigail displays, we can read this as a commentary upon the assumptions made about female sexuality, not only in terms of the Salem witch trials but as they apply to similar events throughout history. Miller astutely utilizes this trope as a way of humanizing the history of these events, to help make the fallible behavior of the characters resonate with modern audiences.