Positive reinforcement involves providing a reward for a desired action or behavior. Positive reinforcement has been used by parents and teachers to help children learn expected behaviors through reward systems for positive behaviors or lack of rewards for negative behaviors. Positive reinforcement can be used for almost any desired behavior that a teacher would like to see in a student. For example, if a teacher would like the students to line up quietly for recess, she can reward the entire class with 10 extra minutes of play time for performing this task correctly.
Negative reinforcement involves increasing a desired behavior by removing a negative consequence when the behavior is performed. Children will avoid a negative behavior to avoid the negative consequence and be motivated to perform a positive task. For example, if the teacher expects children to line up quietly for recess and one child does not, he will lose 10 minutes of extra play time. The idea is this will motivate the child to line up quietly next time to avoid losing recess time.
Children tend to thrive on receiving rewards for positive behavior, so the idea of positive reinforcement tends to be respected by child development specialists and teachers alike. Children who receive rewards for doing well will want to repeat the behavior in the hopes of receiving the reward again. The downside of positive reinforcement is that the child may only perform the task or behavior to get the reward rather than because he is intrinsically motivated to do so.
Children want to avoid negative consequences but also may quickly forget about the consequence after it is executed. It may take many more attempts to have a child learn through negative reinforcement due to this reason, especially for younger children. However, once children learn the same consequence will occur each time the negative behavior does, they will be more likely to stop the behavior and act more positively. This is why consistency is important when using negative reinforcement.
It will really depend on the child and his learning style. Some children can receive a reward several times and begin to generalize the behavior to every day life while others may not. Some children will respond better to a negative consequence and learn to avoid the behavior for that reason. You will need to use trial and error with your students to see how each learns and what method will work best for each student and your class as a whole.