When Jackson sees Rose up close, guessing correctly that she’s pregnant, Mike Nichols’ classic merges with Roman Polanski’s Rosemary’s Baby , before evolving again to suggest a psychological female relationship of unifying identities akin to Ingmar Bergman’s Persona (already a heavy inspiration for Madeline’s Madeline ).
It’s easy to cite Edward Albee’s Who’s Afraid of Virginia Woolf? as inspiration for the machinations of Shirley , but it also taps into my favorite genre of cinema that I’ll simply refer to as “Persona-esque” (as insufferable as that sounds).
There are a lot of influences bubbling under the surface of Shirley, such as Who's Afraid of Virginia Woolf? and Bergman's Persona (a film with which feminist filmmakers seem to have a love/hate relationship), but the director's vision emerges as something more than the sum of its parts.
There’s a bit of “Persona” to the relationship, as which woman is the stronger is always in question until very nearly the end.