Here's the relevant section of the book:
"As the child grows, the parents' own identity may become more and more involved with the child's development. Simultaneously, as the child's needs become more complicated and better articulated, he or she may start to infringe more obviously on the parent system. A cranky infant who demands parental attention at an inconvenient time can, after all, be placed in a crib with the door shut. An irate and tearful nine-year-old is an entirely different matter.
As the child's psychological needs become more of a factor in the life of the family, the narcissistic family truly develops. The parent system is unable to adapt to meet the child's needs, and the child, in order to survive, must be the one to adapt. The inversion process starts: the responsibility for meeting needs gradually shifts from the parent to the child. Whereas in infancy the parents may have met the needs of the child, now the child is more and more attempting to meet the needs of the parent, for only in this way can the former gain attention, acceptance, and approval.
In infancy, the baby's normal development is often rewarding to - and therefore rewarded by - the parents. For instance, the baby's smiles (gas or not!) are usually a source of pleasure for the parents and are greeted with excited voices, attention, cuddles. Eating, sitting up, movement, noises and attempts at vocalization are all usually both rewarding and rewarded. The child's needs and the parents' needs are in sync; there is no problem.
The youngster's normal development, however, may pose a threat to the parents. The toddler's exploration requires vigilance and patience; her shouts of "No!" and "Mine!" can be infuriating and embarrassing. The preschooler's questions and demands are intrusive and time-consuming. Further, the needs of children - especially the emotional needs - increase geometrically as their tractability decreases. As a normal child develops, her need to please herself and her friends increases as her need to please her parents decreases.
In a healthy family, however annoying this fact of life may be, it still does not change the basic conceptualization of parental responsibility: the parents' job is to meet the child's needs, not vice versa. In the narcissistic family, though, as the child's need for differentiation and fulfillment of emotional needs escalates with normal development, so does the parents' belief that their child is intentionally thwarting them, becoming increasingly selfish, and so forth. The parents, feeling threatened, thus "dig in their heels" and expect the child more and moer to meet parental needs Somewhere between infancy and adolescence, the parents lose the focus (if they ever had it) and stop seeing the child as a discrete individual with feelings and needs to be validated and met.
The child becomes, instead, an extension of the parents. Normal emotional growth is seen as selfish or deficient, and this is what the parents mirror to the child. For the child to get approval, she must meet a spoken or unspoken need of the parent; approval is contingent on the child meeting the parent system's needs." - p. 29
"...in the narcissistic family, the children may get their emotional needs met by accident - as a by-product of the parent system's getting its needs met. For example, Susie (age six) has a need to be nurtured. Susie's mother is usually "too busy"... to meet this need, and she demands that Susie's older sister, Joyce (age twelve) "get her out of my hair!" Susie does not get her needs for nurturance met by Mom; Joyce does not get her needs for either nurturance or autonomy met by Mom.
But suppose that the mother-in-law comes for a visit. Mom has needs for praise and esteem from her mother-in-law, who values good parenting. So, during the visit, Mom is available and cuddly to both her daughters. Susie and Joyce get their nurturance needs met, and Joyce gets some time free from baby-sitting and mothering her little sister. The mother-in-law praises Mom's parenting, so Mom gets her esteem needs met. Everybody is happy - temporarily. Mom met the children's needs, but only as an action coincident to getting her own needs met.
In the previous example, the effects are particularly damaging. The children may believe that they caused Mom to be more loving, which will encourage them to believe they have control over her actions. When Mom reverts to form, they may then believe that they have caused the rejection too. They cannot win: they are taking responsibility for things they do not control. The only lesson they can learn from this pattern is that they have not gotten it right - yet. There is really something wrong with them; they got it right briefly, and then they blew it. The children will continue to try to hit the moving target - in this case, the "button" that causes their mother to nurture them." - p. 37