I have found only one really good use for explicit positive reinforcement with my kids: changing frowns into smiles. All of our kids went through a period of "I want" and "Gimme," with "please" reluctantly appended. But the request usually occurred with a frown or a whine. We made it explicit that a frown plus "I want" invariably resulted in a "no," but when accompanied by a cheery smile; it might result in a "yes."
Darryl, just four, has been whining and pouting for several days running at bedtime about wanting to stay up for another ten minutes. The next morning, Mandy sits him down for a chat. "Darryl," she says, drawing a face with no mouth on a piece of paper, "what face have you been showing at bedtime?" Darryl draws a big frown in the circle.
"What have you been frowning about at bedtime?"
''I want to stay up and keep playing. "
"So you've been frowning and whining and complaining at me then, right?"
"Right."
''Is it getting you what you want? Is Mommy letting you stay up for an extra ten minutes when you whine and complain?"
"No."
"What kind of a face do you think will get Mommy to let you stay up a bit longer?" asks Mandy, drawing another mouthless face.
“A smiley face?" guesses Darryl, drawing an upturned mouth.
"You bet. Try it out. It usually works." And it does.