As the women note, Minnie used to sing before she married John Wright. Martha theorizes that after Minnie's marriage, she was prevented from singing, or doing anything else which would have yielded her pleasure, by her husband. Minnie's plight is represented by Martha as a spiritual death, symbolized in the strangling of her songbird companion.
Another point worth noting is that both Martha and Mrs. Peters express guilt over not having visited Minnie more often—a reading which opens up the possibility that Martha's reading of the evidence is skewed by her own feelings that she should have helped Minnie.
Minnie is embodied in her kitchen and sewing things. The cold weather freezes and breaks her preserve jars, symbolizing the cold environment of her home breaking her spirit, as well as the coldness which causes the characters to fail in human empathy towards each other. The bare kitchen can be seen as symbol of the lives of the former inhabitants.
The male characters are clear symbols of "law" and cold rationality, while the women display an intuitiveness representative of the psychoanalytic movement, evoking an interrogation of the value of superficial rational thought.
Mrs. Wright also acts as the "invisible" heroine for women's rights as the play was written and set during the suffragette movement.