When you were a young child, how did it feel to have to be put into time out? To go down to the principal's office? To be subjected to the dreaded words, "I'm going to count to TEN."? Were these threats and punishments an effective way to shape your behavior? Although my parents thought so, B. F. Skinner would have answered that question with a vehement "no."
Punishment may stop a child's naughty behavior for the short term, but Skinner was more concerned about its long-term consequences. First, punishment does not teach a child appropriate behaviors, it only penalizes bad ones. In the long term, use of punishment may also encourage the child not to get caught behaving badly--not to stop. Furthermore, punishment leads to stress--it causes the child to be nervous and anxious, and interferes with their ability to learn. In the end, punishment may cause the child to grow up to be a more aggressive person.
As a future teacher, these are the lessons that I will take with me most. Hopefully, future students in my classroom will benefit from the lessons that I learned here--at the very least, they won't be making many trips to the principal's office!