Final answer:
Child regression upon the arrival of a new sibling may involve a return to previous behaviors seeking attention. Older siblings thrust into a parental role may experience long-term effects. Family dynamics, including shifts in attention and responsibilities associated with birth order, can significantly impact children's behavior and development.
Step-by-step explanation:
Regression in children can manifest when a new sibling is born as it represents a significant shift in family dynamics. The child may exhibit behaviors they had outgrown, such as thumb-sucking, bed-wetting, or tantrums. This can be considered a cry for attention and a step back from developmental progress due to the change in parental attention and family structure.
Parentified siblings may face additional stressors. Older siblings acting in a parental role during times of familial disruption, such as a divorce, can be overwhelmed by the complexities of their responsibilities. This can lead to long-term effects on their mental health and social relationships, potentially manifesting as compulsive disorders or issues with self-care and interpersonal relationships.
Newborn siblings also impact the family hierarchy, which can affect children's development. According to the psychologist Adler, birth order plays a role in shaping personality. For example, the eldest child may become an overachiever, while the middle child may act as a mediator.