The producers of the movie , unlike the play , decided to show you the girls and tituba dancing in the forest -why ?

The ability to film a scene rather than direct a play gave the producers the abiliity to show the scene Parris witnessed, rather than imagine it in our own minds. As written, the audience would only be able to picture the event in reaction to the dialogue on stage. Film allows us to see it for ourselves and to better understand Parris' reaction, as well as react to it in our own way.

we must in the long run decide how suceptible the girls are to the influence of song and dance. It might have been usefull in the play but harder to set and change scenery;