Children have a way of getting through with their demands; they will often convince their parents using various methods including withdrawal to attract their parent’s attention. When children realize that they have the power to influence the parents, they will take advantage of it and use it to get more from them.
Betty’s behavior came by after her parents decided to give in into her requests of sleeping with her. It has further been enhanced by the presence of a stimulus that is the continuous acceptance of her parents to sleep on their bed and the fact that she has seen the same on TV. The parents have been too lenient on her tolerating the fact that she wants to sleep with them while they are not comfortable with it.
Operant conditioning can be used in this situation, if they figure out on something to keep Betty happy; they should use it to encourage her to sleep alone in her bed. They can provide something she likes when she agrees to sleep on her own while at the same time withdraw it whenever she does not agree on sleeping alone.
There has been no proof of lower intelligent quotient to children by the fact that they are young and hence this means that age should not be a justification for continued tolerance of behavior that they disapprove.
I disagree with the saying that you can’t teach dog new tricks. This is because all possible means including positive method of gifts on compliance and negative method of punishment in case of resistance. The first method of gifts and cooperation would be recommended but in case it proves impossible then they should opt for punishment to force her to learn to sleep on her own.
References
Golombok, S. (2009). Parenting: What Really Counts? New York: Psychology Press.
Salkind, N. (2009). Child Development. New York: Macmillan Reference USA.