I conducted a search on Google Scholar a few days ago using “birth order” as search words (as appearing in titles of the cataloged documents). I obtained 2,720 hits. Scholars and lay people alike are fascinated by the effect of birth order on a wide range of human phenomena. One common premise is that the effects of birth order manifest themselves via the differential expectations and norms imposed by parents on their children. Another commonality across most birth order research is that it has been conducted void of an understanding of the Darwinian forces that shape family dynamics. And then came long Dr. Frank Sulloway.
Frank Sulloway’s Born to Rebel: Birth Order, Family Dynamics, and Creative Lives (1996) explored the effects of birth order from a Darwinian perspective. Specifically, Sulloway argues that when children are born, they seek to occupy unique niches in their parents’ eyes. For example, a firstborn might take up the “I am a conforming and obedient child” niche. As the number of offspring increase, there are fewer unoccupied niches to choose from. Sulloway argued that this has an effect on one’s personality such that laterborns are more likely to be open to new experiences and to think outside the proverbial box. His theory is radically different from existing birth order theories in that he is positing that it is the child and not the parent that is driving the birth order effect. He tested his theory by looking at the 28 most radical scientific theories in the history of human thought, and subsequently identified the birth order of those who either espoused and supported the theories or were staunchly against such novel and radical ideas. He predicted that laterborns would be the overwhelming drivers of scientific innovations whereas firstborns would be the most vehement supporters of the status quo. His hypothesis was supported for 23 out of the 28 studied cases, a highly significant effect.