Praising a young child for acting or behaving a certain way creates a chain reaction in other children. Once a child sees or hears another child being acknowledged for doing something right in the eye's of the teacher, other children will often try to mimic the same behavior to receive the same praise. Saying something like "I really like how Samantha is sitting still and listening to me speak," causes other children to stop and look at Samantha to try to model her behavior.
Students who receive positive praise from their teacher often feel a sense of encouragement to perform well. Saying "good job" or "keep up the good work" motivates students to do well or continue doing what they're doing. These simple motivators creates a chain reaction in a student's behavior as it encourages students to continue working to seek additional praise for their work. Praise can help build self-esteem in a child and make children feel like they've achieved something positive.
Praising an individual or group of students for good behavior serves as a reminder and a positive reinforcement for the way you expect children to behave in the classroom. Saying "That was nice of you to share your crayons," or "Thank you for being quiet while our principal visited us," helps reinforce good behavior. Acknowledging and praising students can help improve their interaction with others and authoritative individuals, like other adults, teachers and administrators.
Effective praise is a way of providing individual feedback to students. Saying "You did a lot better on your quiz," to a student privately lets him know he improved on his classwork. Since the comment is being directed at one student, he doesn't need to feel like he's being compared to others. When positive feedback is used in the classroom, students don't necessarily fear continuous evaluation, as praise is part of the learning process.