The impact of the story depends on Jackson's creating a recognizable, congenial setting, then placing within it a horrifying event. What is her purpose in doing this? What social comments does Jackson seem to be making in "The Lottery"?
The setting of the story is recognizable, yet generic enough to be just about anywhere in any time period. Jackson's use of a vaguely recognizable setting allows the violent twist to the story to have more impact. Most readers do not anticipate the violent ending upon first reading the story, though clues are given throughout the story (the gathering of stones and Old Man Warner's citation of "Lottery in June, corn be heavy soon"--seeming to indicate that human sacrifice may have been used to assure good crops--being just two examples).
Jacskon seems to be making several comments about society:
1. Humans tend to blindly follow tradition, often without truly understanding why. Many times the reason given is, "That's how it has always been done," whether the tradition in question is a valuable one or not. The story states that no one really remembers how or why the lottery was started, yet it is seen as a very important tradition in the community.
2. Communities often feel the need for a scapegoat. Fair or not, people often feel better about a negative situation if there is someone to blame. Tessie's "friends" immediately turn on her once she is chosen, and they don't seem to give a second thought to what they are about to do, only that they need to hurry up and end the ritual in order to get home.
3. Humanity is often very resistant to change. No one seems to give much credence to the idea of ending the lottery, even though neighboring communities are rumored to have done so.
Jackson's social commentary is that people can condone inhumanity for some supposedly higher purpose. Also, a blind adherence to a certain behavior can cause its original significance to be lost.
In her story published in the wake of World War II, Shirley Jackson's purpose in writing "The Lottery" points to how real human atrocities have occurred, but have been simply ignored or mitigated in the minds of people as they have gone about their lives that they believe are improved by these "necessary" measures to rid themselves of some greater evil.
The people had done it so many times that they only half listened to the directions....
This unthinking adherence to ritual and custom causes people to forget the significance or morality of their traditional acts. Old Man Warner, for instance, claims that the community has always performed the lottery as long as he can remember; therefore, in his way of thinking, to not do so would be ridiculous. However, in his adherence to this tradition of drawing lots, he neglects to consider the morality of what has been done each year.