Mrs. Hale both supports and challenges the assumptions the men make. She is a dutiful wife and does what her husband tells her to do. She engages in womanly activities and allows the men to do their duties without interfering. However, she insidiously conspires to hide the evidence of Minnie's guilt. Her intelligence and her quick thinking challenge the assumptions for the audience, but not for the men in the play.
The mere title of the play tells you everything you need to know. They continue to laugh and smile condescendingly at the women and the things they talk about--whether or not Minnie intended to quilt or knot her quilt, if they should tell her all her fruit jars busted up in the cold, or what happened to the bird which probably occupied the empty and broken birdcage they found. They assume that women are not capable of intelligent and logical thought; that all they busy themselves with are "trifles"--unimportant tidbits that couldn't possibly offer any evidence to point to Minnie's guilt or innocence. Women are unthinking, silly creatures who waste much of their day dealing with unimportant and silly things. Too emotional, too caught up in gossip, worrying about everything...they are to be taken care of as children are because they can't be trusted to deal with things as a man can.
The men think the women know little about law and even less about evidence. The men are trying to figure out the motivation for the crime, and make fun of the women who sit and talk about silly things like quilting and worrying about the preserved fruit freezing. It is these details, of course, which provide the motivation for the crime. The play celebrates “women’s ways of knowing”, empathy, and female camaraderie, while it satirizes men’s “ways of knowing” and male condescension toward women.