What evidence supports Alfred Adler's proposed Birth Order Theory?
According to Adler's birth order theory, first-born children who later have younger siblings, experience personality problems later in life. Middle born children interestingly are not subject to personality problems as they are not pampered as their older sibling was, but are still afforded the attention. The youngest children, who grow up experiencing the least amount of power in the whole family, may be more likely to experience personality problems later in life.
Alfred Adler's Birth Order theory basically proposes that there are subtle and inherent roles that are indirectly assigned to each sibling depending on the number that they make in the family. Although there is enough validity to support the claim that birth order is influential, theories cannot be applied interchangeably to individuals, because they are not scientifically approved as facts. However, two strong determinants that may confer more validity to the claims of birth order theory are sibling rivalry and the middle child syndrome.
Sibling rivalry occurs when parents unconsciously (or sometimes quite consciously) openly favor one child over another. This is often dependent upon the parents, and not the child, but the result is that siblings who feel favored will want to use their birth order as further proof of their qualification to be the favorites. Research suggests that academic achievement and birth order have a correlation where the first born is often academically successful.
Also proposed by Alfred Adler is the "middle child syndrome". According to Adler, the middle child is often left forgotten in the dynamics of dividing time and attention between the elder and the younger siblings. Hence, the middle child may invariably lack the attention and self-esteem that are often abundant in children who are well-taken care of.
However, there is still much more research to do under other variables to determine whether Adler's theory can actually extend to every socioeconomic level, culture, and ethnicity. Similarly, more studies concerning only children may help level out or maybe even contrast Adler's claims since only children have no siblings to be compared with.
Therefore, while the theory is just a theory, we could conclude that it is parental care, and not merely birth order, what determines the amount of attention that a child gets, or the successes that they will accomplish.
This old theory, really a fight between nurture and nature, has little or no empirical evidence to back it up. While there is some agreement that the order of birth affects the amount of parental attention give at crucial developmental stages, the connection between child-rearing and “problems” at maturity has not been satisfactorily documented. Sociopathy and antisocial behavior have many causes, none scientifically related to birth order. The cause-effect relationships are oversimple, and Adler is seldom cited in child psychology texts today. Piaget, criminal psychologists, etc. have moved past the speculations of simple birth-order theories. Much more relevant are societal conditions—poverty, broken families, real psychological illness, etc.—than whether an infant took attention away from an older child too soon, or whether the eldest child had to take on parental roles too soon. There is nothing physiological or medical in play in birth rate, except for the effect on the mother of multiple births.