why is he so jealous?

In my previous post I talked about a training we attended with Scott Chaussee. In that training we also asked this psychologist about some odd behaviors that our foster son, Jeremiah, is displaying.
Jeremiah gets extremely jealous of Payton when we are holding or hugging her. He gets very angry and will come over to us, try to push her away, and will even hit her. We have been quite surprised by this, as he is the second child. Payton has always been around, it’s nothing new.
Scott Chaussee said that when children are deprived of something as an infant (whether it be food or attention) they tend to crave it when they begin to receive it. We have heard of this happening many times in regard to food issues in foster children, but we never attributed it to a child who lacked physical attention in their first years of life. This is exactly what happened to this little guy.
When a young child isn’t fed much or erratically, they hoard food when it is given to them (as in when they are in a foster home with adequate food provided). Scott equated  this to what Jeremiah is experiencing with affection. He lacked the appropriate attention needed in his first few months of life (even the time in-utero affects this), and now that he feels safe and secure, he’s going to make sure he always has enough.