In Harper Lee's To Kill a Mockingbird, we actually don't learn a great deal about the reactions of the jury members during the trial. Instead, Scout narrates a great deal about the reactions of the spectators of the trial. However, there are a few things we learn about the jury.

First, we learn that Mr. Gilmer, the prosecuting attorney, has a lazy eye, or as Scout describes it, a "slight cast in one of his eyes" (Ch. 17). Scout further notes that Mr. Gilmer uses his lazy eye to his advantage because the jury and the witnesses think he is staring at them when he is actually not. To that effect, the jury pays very close attention whenever Mr. Gilmer is speaking before the court. Hence, one of the reactions of the jury members during the trial is to pay very close attention; Scout even describes the members of the jury as sitting "straight and alert" (Ch. 16).

One moment of particular interest is when Atticus has Bob Ewell write his name before the court. The entire court becomes very interested in the fact that Ewell writes with his left hand. Particularly noteworthy is the jury's reaction, which Scout details in the following:

The jury was watching him, one man was leaning forward with his hands over the railing. (Ch. 17)

Scout's description of the jury's reaction shows that the members fully understand the importance of the evidence Ewell has just inadvertently presented that confirms he is left-handed.

Another moment of interest is when Atticus gives his closing remarks to the jury. Scout narrates that, as he spoke, he "walked slowly up and down in front of the jury" (Ch. 20). She further describes that the members of the jury paid very careful attention as he spoke, following him with their eyes and looking at him with "what seemed to be appreciation" (Ch. 20).

Yet, despite the fact that the members of the jury recognized the importance of the evidence presented and appreciated Atticus, the members still allowed racial prejudice to cloud their judgement and returned with a guilty verdict.