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Birth Order's Effect on Personality

Lauren McD's picture

      Does birth order really affect a person’s personality? This question has been looming over the psychology world for a long time, beginning with the research of Alfred Adler in the early 20th century. While the views on Adler’s theories are currently almost as skeptical as Freud’s radical theories, Adler sparked the controversy that scientists still debate today. (1) The majority of psychologists think birth order does not have an effect on personality, but the topic is still a widely debated disagreement that remains unanswered. (3) Despite numerous research projects, scientists are still concluding answers that do not align, leaving the public mystified. Can someone’s personality really be attributed to their age rank amongst their siblings?

      Typical birth order stereotypes for each sibling position are generally universal throughout the scientific community, regardless of whether or not the scientist supports the stereotype. An only child generally follows the pattern of seeking relationships with adults, liking attention, and having difficulties sharing. (1,4) The eldest child is generally described as authoritative, strict, direct, and confrontational. (1,4) Also, he has a higher level of self confidence, is more likely to accept the status quo, and is more likely to be found in political office due to his sense of motivation. (4,6) The middle children are known to get the ‘worst deal’ across the board. They are constantly being compared to their other siblings and have trouble finding a place in their families. (1,5) According to Frank Sulloway, they have intermediate levels of radicalism. (6) The youngest child is usually spoiled and a dreamer. (1) He is more agreeable than his older siblings, in contrast to their direct and confrontational attitudes. (6) However, the most common description found of the youngest sibling is in the form of one word: rebellious. The theory is that the youngest cannot do what the other siblings can, and as a result, lashes out. (5,6) His personal freedom is a priority, and he leaves responsibilities to others. In general, he supports radical theories, is a risk taker, and adventurous. (5,6)

      For my own family, this stereotype certainly holds true; I’m the oldest sibling, and well known for being an overachiever, confident, and reliable. The description of ‘authoritative’ is certainly not an adjective I would choose to describe myself. However, I suppose in comparison to my younger brother, I would claim the word. In public situations, my brother refuses to take initiative or stand up for himself in something as simple as ordering pizza. My younger brother is the rebel in our family, constantly arguing with our parents. His lack of motivation frustrates the rest of our family to a great extent; if he only applied himself to his schoolwork, I have no doubt he would achieve high grades. I cannot personally test all the stereotypes of the birth order theory, since I only have one sibling. However, I can confidently claim that in terms of the oldest and youngest child, my family is a relatively definite example of the birth order theory.

      Birth order theorists would claim my family is a typical example of characteristic traits for all families. There are still some researchers who claim the birth order personalities outlined above have merit. Paulhus, Trapnell, and Chen are adamant about its accuracy, and various sources claim there is ample evidence to support the theory. (3,4,6) Proof that this side of the table manages to muster up is that first children are more likely to be found in political office. (4) Since a general personality comprised of motivation, leadership, and confidence seems to accompany a politician, this source claims this statistical evidence is in support of the birth order theory. Also, well-known leaders of revolutions such as Jefferson, Marx, and Castro were younger brothers, supporting the statement that younger siblings are more rebellious. (5) In a specific survey of marijuana usage in families, Zweigenhaft found that younger siblings are more likely to use the drug, supposedly because of their rebellious nature. (6) The sources summarized their own theories in order to explain the research in support of the birth order theory. Sulloway suggests that siblings are competing for a niche in their family, much like Darwinian theory. The differences in personality of the children are not a result of different treatment by the parents, but a result of the different statuses of the siblings. (6) In response to more eldest children retaining political office, Hudson says that the need for political power is related to the power obtained during childhood as an older sibling. (4)

      There is far more support for the side of the debate against the birth order theory. Various sources claim there is no physical evidence of the theory. (3,4,6) Harris and Dalton Conley claim that people who do believe in the theory are merely inventing hind-sight rationalizations. This idea is one that we’ve all seen in scientific research; just because the researcher wants the evidence to be there does not mean that it is. With something as subjective as personality, it is often difficult to remain objective during research. In terms of proof, the study conducted by Zweigenhaft concluded that younger children are not more likely to participate in protests, showing that they are no more rebellious than their other siblings. (6) This is interesting because Zweigenhaft conducted two surveys: the marijuana survey cited above and this protest survey. The results of the surveys contradict each other: the marijuana survey is in support of the birth order theory, while the protest survey is not. The study does not make any significant headway in either direction of the debate, but birth order theorists may argue that marijuana usage and protest participation are not reasonable measures of rebellion. This study observed actions, but not personalities. Perhaps what makes this dispute so difficult to settle is that people have different ideas of the word ‘rebellious’ relating to different things. Some people may think rebellion is using marijuana, while others think it is changing one’s own beliefs to specifically not conform to the general masses. These claims outlined above are no match for Harris’ strong argument that siblings may hold the stereotypes assigned to them within the family, but not outside of the family. In conducted surveys, parents have been noted to describe their own children within the birth order stereotypes, even if the children may not behave that way outside of the home. It has also been shown that children dominated by siblings at home are no more likely to be dominated by peers. (3)

      There are many explanations of the lack of correlation to the birth order theory; many theorists make the valid point that other factors besides birth order, such as social class, family size, and death in the family, are more important than birth order in molding children’s personalities. (5,6) However, the most supported explanation is Harris’ theory that children only retain their ‘assigned’ personality in the family context. She supports this theory by saying that in everyday situations, a similar transfer of personality only occurs if the new context is highly similar to the old. (3) In order to produce a somewhat similar output of human behavior, we need similar inputs. In Malcolm Gladwell’s book, he cites Harris’ theory in support of his own: that people act differently in different situations and cannot be described with single-word adjectives. Gladwell states that it is easier to define people only in terms of the personality that we see the most often. (2) Harris’ argument runs along the same lines; she states that we mostly make judgments of who we know to the best extent. These people are generally people we know in a family context. We observe the personalities of siblings in their families, and assume that these personalities hold true in outside contexts. (3) I wonder if earlier researchers of the birth order theory ever pondered this possibility. If not, I am curious if this new idea would have caused their conclusions to switch sides. This idea is most agreeable in my mind because it is an intermediate answer to the discussion and explains the disparity amongst the other research. When I think about it, I only know my brother when he is in the context of our immediate family. I could not possibly know how he acts around his friends, teachers, or any other group of people without being there and inducing a family context. Maybe he takes on a more authoritative role or acts less rebellious in these instances.

      What Harris and Gladwell both suggest is that personality is not a well-defined list of attributes, but instead is a complex interaction of attributes that depend on the situation we find ourselves in. (2,3) Did the earlier researchers believe in this idea? The first headway in the exploration of personality focused more on defining a specific personality, and still does. When I took the Myers-Briggs personality test in high school, the test did ask about personality in different situations. The overall outcome, however, was simply a list of qualities of a personality, without attributing to the different situations. Perhaps it is easier, as Gladwell suggests, for this test to take the average of one’s personality in different situations. Maybe we need to stop assigning personality types and accept that people act differently in different situations.

      Harris also makes another suggestion, pulling information from the endless ‘nature vs. nurture’ controversy. She claims that personality is mostly based on genetics, but also has an environmental factor, which is something most scientists are aware of. She makes the statement that the correlations of personality in and out of the home are due to the genetic factor, while the differences are due to the environmental factor. (3) This is further suggesting that context has a great role in people’s behavior.

      It seems as if the birth order theory will never be truly resolved in the scientific community. I agree most with the statement that the stereotypes of siblings only hold true in the home, especially after a close reading of Gladwell’s book. However, I do not have the capacity to conduct a study for myself, and I cannot trust either side of the debate, since conclusions on the same study differ so greatly. Even though this mystery remains unresolved, the explorations into the topic still reveal much about human personality and behavior. Perhaps it would be a more interesting topic to delve into the strictly biological aspect of the differences in personality and birth order, which may provide more proof on the subject. I believe more research into the birth order theory, while maybe not discovering a concrete conclusion, will uncover neurobiological insights that can assist us in explaining the complexities of human personality.





1)"Alderian Overview of Birth Order Characteristics." Minnesota State University. 6 May 2010.

2) Gladwell, Malcolm. The Tipping Point. New York: Little, Brown and Company, 2000.

3) Harris, Judith Rich. "Context-Specific Learning, Personality, and Birth Order." Current Directions in Psychological Science 9.5 (2000): 174-177. 7 May 2010.

4) Hudson, Valerie M. "Birth Order of World Leaders: An Exploratory Analysis of Effects on Personality and Behavior." Political Psychology 11.3 (1990): 583-601. 7 May 2010.

5) Stossel, John. "Does Birth Order Determine Personality?" ABC News (2004): 7 May 2010.

6) Zweigenhaft, Richard L. "Birth Order Effects and Rebelliousness: Political Activism and Involvement with Marijuana." Political Psychology 23.2 (2002): 219-233. 7 May 2010.


Serendip Visitor's picture

im the middle child and in my

im the middle child and in my family this didnt fit we all were differnt then the theory