Positive vs. Negative Reinforcement

Should we reward a child for doing something that is expected, in hopes to increase the behavior, or take something away from a child because they behavior in a poor manner? This question is at the forefront of my mind every day when I step inside the classroom. I struggle with what the correct response would be. For me, I am a 7th and 8th grade teacher in the inner city of Atlantic City. My students are not very well off, deal with shootings on a daily basis, and have to fear for their lives every time they enter the street. How am I supposed to punish them for an action they may not know any better, but at the same time should I reward them because they said please and thank you for a week? I tend to take my background and confuse what is understood and what is taught. It was understood by me as a child, I was not being rewarded for something I was expected to do. However, when their are little expectations outside of the classroom, how do you punish a child for not knowing any better?

The biggest wake up call I had of this, was last year. I was in my second year of teaching, and had an 8th grade homeroom. In January, on a Wednesday after school, I was delivered the devastating news that the child I was mentoring, was shot and killed by one of my previous students. I couldn't function, I couldn't speak, and I certainly couldn't hold any child accountable for their actions, when I couldn't think of my own. However, I had children coming to school wanting to fight the other side, wanting to scream at each other because they couldn't deal with their thoughts or emotions, and couldn't understand how their friend and classmate could kill another classmate. As a leader, I had to make the painful decision, of deciding how to explain the wrongdoings of one student while not showing favoritism, choosing a side, or lightening the emotional load. Should the child be punished for life? Should we reward other students for being there but not retaliating? Should we take the life of a 14 year old kid and throw him in jail with no hopes of redemption or do we allow redemption to happen? As a product of their environment, how do we choose the right side?