Simplify the following text for a Grade 11 native English-speaking person.
Original: In the 1970s and 1980s , Austen studies was influenced by Sandra Gilbert and Susan Gubar 's seminal The Madwoman in the Attic ( 1979 ) , which contrasts the `` decorous surfaces '' with the `` explosive anger '' of 19th-century female English writers .
Simplified: In the 1970s and 1980s , Austen studies was influenced by Sandra Gilbert and Susan Gubar 's The Madwoman in the Attic ( 1979 ) . The Madwoman in the Attic explores the `` explosive anger '' of nineteenth-century female English writers under their `` decorous ( proper ) surfaces '' .