I've been reading
Why People Believe Weird Things (by Michael Shermer), and it mentions a rather interesting study. It was conducted by a man named Frank Sulloway in 1996, and examines a person's tendency to reject or accept radical theories based on a large number of different variables. Apparently there is a very strong correlation between their ability to accept radical theories and the order in which they were born in relation to their siblings.
Michael Shermer wrote:Consulting over a hundred historians of science, Sulloway had them evaluate the stances taken by 3,892 participants in twenty-eight disparate scientific controversies dating from 1543 to 1967. Sulloway, himself a laterborn, found that the likelihood of accepting a revolutionary idea is 3.1 times greater for laterborns than firstborns; for radical revolutions, the likelihood is 4.7 times higher. Sulloway noted that "the likelihood of this happening by chance is virtually nil." Historically, this indicates that "laterborns have indeed generally introduced and supported other major conceptual transformations over the protests of their firstborn colleagues. Even when the principal leaders of the new theory occasionally turn out to be firstborns--as was the case with Newton, Einstein, and Lavoisier--the opponents as a whole are still predominantly firstborns, and the converts continue to be mostly laterborns" (p. 6). As a "control group" of sorts, Sulloway examined data from only children and found only children wedged between firstborns and laterborns in their support for radical theories...He noted that laterborns tended "to prefer statistical or probabilistic views of the world (Darwinian natural selection and quantum mechanics, for example) to a worldview premised on predictability and order." By contrast, he found that when firstborns did accept new theories, they were typically theories of the more conservative type, "theories that typically reaffirm the social, religious, and political status quo and that also emphasize hierarchy, order, and the possibility of complete scientific certainty" (p. 10).
A couple explanations for this tendency were explored in the book. They basically center around the child's relationship to their parents. One possible explanation is sibling rivalry, that the children compete for parents' attention. Since the firstborn child is bigger and older, they would be more successful in such a competition, and so the younger siblings look into other fields in order to compensate. The other explanation is that parents, being new at the whole thing, naturally give more attention to the firstborn child, which reinforces a tendency to respect authority. Younger siblings, not receiving the same amount of attention, then tend to feel less pressure to follow suit.
Michael Shermer wrote:R. Adams and B. Phillips (1972) and J.S. Kidwell (1981) report that this distribution of attention causes firstborns to strive harder for approval than laterborns, and H. Markus (1981) concluded that firstborns tend to be more anxious, dependent, and conforming than laterborns. I. Hilton (1967), in a mother-child interactive experiment with twenty firstborns, twenty laterborns, and twenty only children, found that at four years of age firstborns were significantly more dependent on and asked more frequently for help or reassurance from their mothers than the laterborn or only children. In addition, mothers were more likely to interfere with a firstborn child's task (constructing a puzzle). Finally, R. Nisbett (1968) showed that laterborns are far more likely to participate in relatively dangerous sports than firstborns, which is linked to risk taking and thus to "heretical" thinking.
