In To Kill a Mockingbird, what lifespan stage, and character(s) would you focus on as you look at biosocial, cognitive...development?
(Consider the psychosocial aspects of what you would expect to see during this stage of life and what you actually see in the story. Other things to consider as you are writing are gender issues, cultural issues and whether the setting of the movie impacts the story being told.)
I am only allowed to answer one of your questions. Each question must be listed separately.
To Kill a Mockingbird is set in 1930s in Maycomb, Alabama, an imaginary town, prior to the Civil Rights Movement of the 1960s. The Civil War has been over since 1865, but the scars and memories are still fresh in this part of the deep South.
In light of the time period and location of the story, I would probably select Scout as the character to study based not only on her stage of life in the story (a girl just beginning to see the world as it really is, and resenting the social restrictions some people—her aunt—try to place on her because she is a girl), but also because she tells the story in the first-person, so we can peek into her thoughts and observe with the clarity of a child (one of Harper Lee's real gifts in the telling of this story) the curiosities of human behavior and the hypocrisy prevalent on so many levels and in so many areas within this community.
For instance, Scout does not understand the hypocrisy demonstrated by one of her teachers who gets very upset about Hitler's murderous march through Europe, when her teacher also acts in a hateful way towards the blacks within their own community. Scout's viewpoint, while seemingly so innocent, gives voice to very astute and adult observations.
Even when the townspeople come to lynch Tom Robinson at the jail, it is Scout's childish voice of reason that turns the mood of the mob around, as she is able to see the individuals in the mob, rather than the mob as a living entity, and her ability to see them as individuals reminds Mr. Cunningham, especially, of the individuality of the man they are trying to kill.
(Note: the movie and the novel have some very specific major differences. The movie is excellent, but a great deal of the novel is left out.)
Since To Kill a Mockingbird is written in first person narrator by Scout, who recounts the narrative as an adult, the narrative does not always reflect the true perspective of Scout as a child. Therefore, if the reader wishes to analyze a character regarding the corollaries between age and perspective, he/she would do better to regard another character such as Scout's brother Jem. Certainly, there are events and incidences in which Jem evinces a continuing maturation. In one instance, Jem calls loudly to Atticus, fearing that the group of men on the front lawn are as threatening as the mob that has previously formed at the jailhouse. In this instance, Jem's reaction demonstrates a maturing loyalty and protection of family; however, his judgment is rather rash. In another instance, Jem demonstrates more maturity. This instance occurs when Dill sneaks into the Finch home and hides under a bed. Whereas in their youthful comaraderie, the children do not disclose such behavior to any adult, Jem feels the necessity of alerting Atticus so that he can contact Dill's mother. Appalled at this traitorous act, Scout berates Jem, but he is stalwart in his mature perspective and explains to Scout the importance of informing Dill's mother to allay her fears.