When we are born into a family unit or brought into adoption or as a step child you take a certain place in the family hierarchy, we become only child, Oldest child, middle child, or youngest child.
The first and most obvious effect of taking a certain position in the family is the relationship we have with respect to the people already there. If there are only adults present, we are in a very close and often intense relationship with them, as any one knows who has had a child, who has watched a first-time parent hovering over their enfants, this constant and close relationship give the first child in the family an opportunity to imitate and learn from these adults to the fullest possible extent. The first child imitates their physical mannerisms and learns speech from them. He learns more things and much of the learning takes place on an unconcious level.
That's is, neither the parnets nor the child verbalize that thus and so is the way to something, the child observes and imitates. You can see that the position in the family affects the child relationships with others.
Relationship with parents.
From the beginning the parents treat the child in accordance with place in the family and soon the child recognises that place. He is the child in the family, and he tends to think of himself as a child in relation to adults. The only child never have any reason to change such perception of his role and he tends to carry into adulthood a strong feeling of being a child in relation to other people.
The first child who becomes the oldest child doesnt have this unlimited time to view himself as a child in the relationship to his parent, when a sibling arrives,