The idea that birth order exerts an inﬂuence on personality has been popular throughout the history of psychology. Psychologists have developed a variety of theories regarding birth order effects. Firstborns have been considered more likely than their later-born siblings to be high achievers, later-born children are supposed to be more popular than their ﬁrst-born siblings, and later-born siblings have been alleged to be overrepresented among contact-sport athletes. These ideas have also ﬂourished outside the academic community. Pop psychologist John Bradshaw, for example, claims that ﬁrstborn children are either conservative, holding values and making decisions consistent with the father; or rebellious, holding and acting on values in opposition to him. He also echoes a long line of writers in assuming that the ﬁrstborn child will have self-esteem problems, that middle children are better able to pick up on “hidden agendas” and tend to operate as intermediaries in family conﬂicts, and that third children feel ambivalent and have trouble making choices.
Certainly the early environment of the ﬁrst child is a different one from that experienced by later siblings. The ﬁrstborn gets all the parental attention for at least the ﬁrst year or so, then has to become accustomed to competing with a rival, whereas the later children have competition from the beginning. The parents are certainly less experienced with the ﬁrst child than they are with later children. It is often claimed that parents give ﬁrstborns more responsibility and less independence. Given all this, it might not be surprising if there are some differences based on birth order.
Most recently, Frank Sulloway resurrected the idea that birth order has a big inﬂuence on almost everything in his book Born to Rebel. He proposes that innovations in scientiﬁc, religious, and political thought tend to be more readily accepted by later-born children, while ﬁrstborn children tend toward conservative opposition to such innovations. He relies on his own reading of history as much as on psychological research, arguing that throughout history, ﬁrstborns have tended to support, and later-born siblings have tended to challenge, the status quo. Focusing on both intellectual and political revolutions, he claims, with little scientiﬁc evidence, that revolutionaries and their supporters were disproportionately likely to be later-born children.
According to Sulloway, within the family, ﬁrst-born children tend to either wholeheartedly embrace or fully reject their parents’ values and beliefs, whereas later-born children are more likely to rebel against their parents’ (and siblings’) ways of doing things. First-born children have ﬁrst shot at their parents’ attention, so they have less motivation to rebel than the later children do. The later born children have to ﬁnd other ways to get attention, so they are more likely to adopt what Sulloway calls heterodox views—in other words, views that deviate from their parents’ accepted beliefs.
In fact, over the last ﬁfty years, the validity of birth-order effects has been debunked by hundreds of studies; no consistent birth-order effects have been documented. The Swiss researchers Ernst and Angst examined nearly forty years of birth-order research and found that some studies found birth-order effects, some did not, and most were inconclusive. Most of the studies that did ﬁnd birth-order effects had serious methodological ﬂaws, including failure to control for other important factors like socioeconomic status and sib ship size (the number of children in the family). The positive studies also tended to use much smaller samples, whereas the studies with large groups failed to ﬁnd anything. This in itself argues against the birth-order effects. Statistically, positive results are much easier to detect with larger sample sizes, so an effect that is actually occurring in the population is more likely to turn up with a larger sample than with a smaller one.
To avoid relying purely on their meta-analysis of other people’s data, Ernst and Angst undertook a study of their own, with a sample that was gigantic by psychological-research standards (7,582 people). Their subjects took personality tests that measured twelve different traits, and the results turned up no differences at all between ﬁrst-and second-born children, and only trivial effects in larger families. Ernst and Angst concluded that birth order is simply not a predictor of personality or behavior and that “this kind of research is a sheer waste of time and money.”
Despite this, birth-order ideas continue to ﬂourish. Sulloway is aware of Ernst and Angst’s conclusions, and he addresses their review of the literature in his book, but he dismisses their conclusions and arrives at some different ones based on his own reading of their data. Sulloway’s rejection of their methods has drawn a fair amount of criticism within the social sciences.
- Ernst, C., and Angst, J. Birth Order: Its Inﬂuence on Personality. Berlin: Springer-Verlag, 1983;
- Spitzer, A. B., and Lewis-Beck, M. S. “Social Science Fiction.” Journal of Interdisciplinary History, 30(2) (1999): 259–272;
- Sulloway, F. J. Born to Rebel: Birth Order, Family Dynamics, and Creative Lives. New York: Pantheon, 1996;
- Townsend, F. “Rebelling against Born to Rebel.” Journal of Social and Evolutionary Systems, 20(2) (1997): 191–205;
- Wrage, S. “Rebelling against Research Methods? Using Frank Sulloway’s Born to Rebel to Teach Research Methods.” International Studies Perspectives, 1(2) (2000): 161–164.