The literary device of the flashback is the most used in The Face on the Milk Carton. These flashbacks show the reader what happened in her past. It is a sort of look into her memory. The incident of the milk carton makes her remember about the little girl's dress.
"She remembered that dress . . . how the collar itched . . . remembered the fabric; it was summer fabric; the wind blew through it . . . remembered how those braids swung like red silk against her cheeks."
The flashbacks typed in italics are triggered by event in her daily life. She is with Reeve and they are starting to eat ice cream sundaes. Suddenly, she remembers when she was kidnapped inthe mall because of a woman who has "long straight cascading hair" who allures her with an ice cream sundae. Janie calls her flashbacks "daymares". She discovers her traumatic past through the flashbacks. This is a literary device where the author lets the reader know about the character's past.