Birth Order Research Paper Thesis Statements

Only child, first-born, last-born, or somewhere in between. Where do you fit into the birth order of your family? Perhaps you’ve come to believe the myths both within your family and in psychology as a whole that your character, values, achievement strivings, and life success are determined by the family position that fate, and your parents, awarded to you. Psychology goes through periods of alternatively accepting and rejecting these myths. Although various theories abound, when you come right down to it, the matter is one that requires the right research approach. Methods are everything in studies of birth order and personality.

Of the many factors to control for, there’s sex of the children, number of years between them (in multiple-child families), and family history, not to mention the right way to study personality. What about step-siblings, half-siblings, and siblings who don’t even know that the other one exists? There are biological and adopted families. Parents vary in their ages and in the ages they were when they had their children. When it comes to psychological variables, the situation becomes even more complex. Do we study actual achievements, and if so, how do we measure them? Income? Education? Occupational prestige or advancement up the career ladder? Should we look at personality, motivation, intelligence, happiness, or mental health?

OK, your methodological head is spinning by now, so we’ll try to make some sense of the latest research, much of which does a better job of controlling for all of these factors than was true in years past. We’ll look at three recent studies, beginning with a dose of reality from distinguished University of Georgia psychologist Alan E. Stewart, who wrote what is perhaps the definitive recent work (2012) on the theory and research on birth order. He bases his paper on 529 journal articles published over a 20-year period. (The sheer number of studies on birth order is a testimony to the importance of this topic in psychology.)

Taking his lead from the original birth order theorist, Alfred Adler (a one-time disciple of Freud), Stewart distinguished between “actual” birth order, or ABO (the numerical rank order into which you are born in your family of origin) and “psychological” birth order, or PBO (self-perceived position in the family). Right away, you’ve probably learned something useful: Your actual birth order need not have the same impact on you as the birth order you believe you have. Actual and psychological birth order can deviate for a number of reasons, including illness of one child, size of family, and degree of separation between siblings. Your role in the family based on your age may not be same as the role you have come to occupy.

As explained by Stewart, using Adler’s framework, the firstborn child (or one with the “oldest” role) would be most likely to take on a leadership position, to like it when people stick to rules and order, and to strive toward achievement goals. The firstborn may be sensitive to being “dethroned” by younger sibs who drain away the attention of parents that the firstborn enjoyed before they came along.

The youngest child may feel less capable and experienced, and perhaps is a bit pampered by parents and even older sibs. As a result, the youngest may develop social skills that will get other people to do things for them, thus contributing to their image as charming and popular.

Then there’s the all-too-easy-to-ignore middle child, who feels robbed of the prized youngest child status, and perhaps feels rejected. On the positive side, the middle child may also develop particularly good social skills in order to keep from being ignored.

For the only child, there’s the possible advantage of receiving all the attention from parents, but this is balanced by the feeling of constantly being scrutinized and controlled.

These brief portraits probably sound quite familiar to you, and they should, because they make up much of the stereotyped mythology about birth order. Adler’s description of these positions is more nuanced than we typically read about in their pop psych translations, but for now, they’ll suffice.

For decades following Adler’s writings, researchers working in the tradition of “individual psychology,” or the Adlerian school of thought, tried without much success to validate the theory. In part, this was because they lacked statistical methods available now, but also because they focused on ABO (i.e. actual) rather than PBO (i.e. psychological). Much of this changed when the Psychological Birth Order Inventory (PBOI) was developed in 1991 by a research team that included Stewart. The PBOI contains items to assess all birth order positions in the family that individuals rate on an agree-disagree scale.

Firstborn items on the PBOI tap feelings of being powerful, important, leading, and achieving (“It was important for me to do things right”). The middle-child items focus on competition, having fewer resources, and feeling unimportant (“It seemed like I was less important than other members of my family”). For the youngest child items, individuals rate themselves on being the boss of the family and getting others to do things for them (“I was pampered by my family members”). Finally, the only child scale tapped those feelings of pressure (“I felt like I lived in a fishbowl”).

Now we’ve got the scales sorted out. Let’s see whether PBO trumps ABO, as Stewart’s model would predict. Taking three examples—rational vs. irrational relationship beliefs, perfectionism, and personality—in each case, the extent of the relationships with PBO were not overwhelmingly large, but they were measurable. Your perceived niche in your family plays a larger role in influencing the adult you’ve become than the actual timing of your birth.

Stewart’s study shows that we’re not fated to live out a life dominated by the accident of the timing of our birth. You can’t change your actual birth order, but you can change the way you think about your role in the family. Sounds like pretty good news, especially if you felt doomed to a life of presumed middle-child insignificance.

Now we’ll take a look at the second contribution, a paper by Daniel Eckstein of Saba University in Netherlands Antilles written with co-author Jason Kaufman (2012).  Examining several areas of family life and sibling relationships, Eckstein and Kaufman tested, among other areas, what’s known as the “Confluence model” developed by Zajonc (1976). According to this view, first-borns are the teachers, and later-borns are the learners. However, as Eckstein and Kaufman point out, first-borns aren’t necessarily the only ones doing the teaching between sibs. If we use the assumption that perceptions count more than reality, it then becomes clear that second-borns can have much to teach their older sibs. The way they approach the task may be different, but the direction isn’t just one-way, as we might otherwise assume.

We'll finish up with the Eckstein and Kaufman paper shortly. The third study bears directly on the point of leadership within the two-child home. Ghent University psychologist Bernd Carette and colleagues (2011) compared the ways that first- and second-borns set goals for themselves. Carette and his fellow researchers limited their study to sibs who were closely spaced in age (averaging 2.5 years). When birth order effects are found, they point out, they tend to be present in this narrow span of time. The theory behind this study was that firstborns would set “self-referenced” or mastery goals (ones that they choose for themselves) and second-borns would set “other-referenced” goals or performance goals (wanting to do well on goals set by others). Firstborns, they argue, would strive for mastery, but second borns would want to do well to hit the targets that someone else set for them, i.e. the older sib. The measure they used tapped mastery goals by asking participants to indicate, for example, whether in their courses they sought to understand the material as much as possible. Questions about performance goals asked whether they wanted to do well compared to other people.

The findings Carette and team report lend statistically significant, but differences of about 2/10 of a point on a 5-point rating scale. They concluded that the findings “show that birth order lies at the heart of people’s goal preferences” (p. 502). Pretty strong stuff. But with the psychological birth order idea in mind, it’s hard not to wonder how much perceived family role influenced these motivational ratings. If you’re convinced that your birth order leads you to be a leader, you’ll behave like a leader.

Let’s return, then, to some of the other implications of your self-assigned birth order, but let’s flip it and see the role of parental perceptions of their children’s birth order. Eckstein and Kaufman point out that perceptions and beliefs about birth order may have their effects, in large part, because parents impose their own stereotypes onto their children. By assigning these stereotyped birth-order roles, which may interact with gender roles, parents create self-fulfilling prophecies among their brood. You come to feel like the leader, if you’re a first-born, because you were handed this role early in your life.

Perceptions about birth order can also influence your choice of a future career. Given the mantle of the achievement-oriented firstborn, you may set your sights higher than do your lowlier, younger, followers. Eckstein and Kaufman cite a study conducted in Poland showing that people believe first-borns to be more likely to occupy high prestige occupations to the tune of a correlation of .76 (out of a possible 1.0). That’s an almost unheard-of statistic in psychology, where the average reported in a published article is about .3 or .4 at most. 

With regard to intelligence, which you have undoubtedly also heard is related to birth order (and fits the Confluence model), the data remain unconvincing: When you add in the stereotype threat effect, which states that people perform on intelligence tests in ways subtly influenced by their self-perceptions, the birth order research becomes even more inherently flawed. If you go around life believing that because you’re a firstborn you’re inevitably smarter, you’ll approach any testing situations with the kind of self-confidence boost that can actually boost your score.  

This is just one example of the impact that perceptions and stereotypes about birth order can have on apparent birth order effects. The moral of the story for parents is to look for your own biases and stereotypes about birth order as you think about what your children are capable of doing. Encourage them to teach each other, to define their own identities in the family, and to avoid labeling themselves based on their birth order. Don’t let the lives of your children be dominated by the random forces that caused them to be born when they were.

Once we define ourselves in terms of who we are, and not when we were born, we’ll be able to open up many more opportunities for fulfillment than even our parents might have dreamed for us.

Follow me on Twitter @swhitbo for daily updates on psychology, health, and aging. Feel free to join my Facebook group, "Fulfillment at Any Age," to discuss today's blog, or to ask further questions about this posting.

Copyright Susan Krauss Whitbourne, Ph.D. 2013.


Carette, B., Anseel, F., & Van Yperen, N. W. (2011). Born to learn or born to win? Birth order effects on achievement goals. Journal of Research In Personality, 45(5), 500-503. doi:10.1016/j.jrp.2011.06.008

Eckstein, D., & Kaufman, J. A. (2012). The role of birth order in personality: An enduring intellectual legacy of Alfred Adler. The Journal of Individual Psychology, 68(1), 60-61.

Stewart, Alan E., (2012). Issues in birth order research methodology: Perspectives form individual psychology. The Journal of Individual Psychology, 68(1), 75-106.

Zajonc, R. B. (1976). Family configuration and intelligence. Science, 192, 227–236.

Birth order is an important factor that helps unveil the mysteries of human behavior. This paper provides an investigation of family relationships and corresponding individual traits that pertain to birth order placement, and how such dynamics impact educational functioning. The firstborn child, who receives a tremendous amount of praise and attention fares exceptionally well in school, whereas later-born children operate at much lower levels. For example, middle children deal with psychological issues of low self-worth and identity crises, whereas the youngest children live in chaotic households that do not necessarily promote learning. The Confluence Model and The Resource Dilution Model shed light on the matter by providing explanations that unearth the relationship between family constellation and performance.

Keywords: Adaptive Cognitive Style; Confluence Model; Deidentification; Innovative Cognitive Style; Resource Dilution Model; U-Shaped Equity Heuristic


The role that birth order plays in shaping behavior has proven to be of significant consequence from ancient to modern-day civilization. The academic literature offers several examples of how firstborn children have upheld supremacy across a variety of contexts (Sulloway, 2007). For instance, the mortality rates of children in the 19th century occurred in epic proportions, and first born children grew to become more physically robust and customarily outlived their younger, frailer siblings (Penn & Smith, 2007). Presumably this was because firstborns were regarded as precious commodities and were indulgently pampered, nourished, and treated in the highest regard by doting parents. Additionally, preferential treatment adorned upon firstborn children has been a practice ceremoniously observed by royal families who have created primogeniture (Hurwich, 1993) infrastructures through which the eldest child is bequeathed successive sovereignty, a most eminent honor.

Even in the animal kingdom, there exist examples of species that favor the survival of firstborns within a family group, such as Verreaux's Black Eagles (Tennesen, 2006), who can only sustain one young chick a time. Thus, upon the arrival of subsequent chicks, the eldest eagle bludgeons his baby sibling to an untimely demise, receiving ostensible consent from parents who stand by and observe what would otherwise be deemed an abomination against nature.

According to an old adage, no two children are raised in the same household, regardless of overtly similar circumstances that impress upon their mutual cultural, religious, neighborhood, and even familial influences. Alfred Adler, a prominent 20th century psychologist and contemporary of Sigmund Freud, not only agreed wholeheartedly with this sentiment, but helped blaze a trail of groundbreaking research and anecdotal knowledge that surrounded the ways in which birth order characteristics molded each individual's personality by sculpting both their strengths and insecurities alike (Croake & Olson, 1977; Watkins Jr., 1992). Since Adler's time, a series of noteworthy researchers have allied their efforts into excavating information on birth order including Frank Sulloway and Robert Zajonc. Provided here is an overview of unique family dynamics that pertain to the assets and struggles of each birth order, and how such factors imbed themselves into the context of academic erudition, or learning styles.

In his theory, Adler identified four distinct sibling placements (i.e., firstborn, second born, middle child, youngest) although the trend in today's society leans toward smaller families (Rogers, 2001). A systemic lens that utilizes circular causality will serve as the framework for this overview, which opposes the notion that behavior follows a linear progression and rather is created by multiple forces that are constantly giving and receiving messages in a roundabout, circuitous fashion (Feinauer & Patterson, 1993; Neimeyer, 1989). For example, although parents ideally respond to the unique needs and characteristics that each child possesses, they also synergistically create those children's needs and characteristics. Hence, each family member contributes toward, and is on the receiving end of birth order manifestations.

Further Insights: Birth Order Theory

The Firstborn Child

The firstborn is a marvel, indeed (Lemen, 2008; Sulloway, 1996). When parents give birth to their eldest child they are constantly in awe of the miracle of life, of the special and delicate forces that came together to create such wonderment. They bask in the glory of their creation, and enthusiastically undergo all the developmental milestones side-by-side with their budding child: the first smile, the first step, the first word. It is difficult for parents to detach themselves from the single-minded focus extended toward such age-appropriate feats, and the newfound feelings of amazement that the firstborn infuses into the hearts of parents renders frequent proclamations of how brilliant, beautiful, funny, and/or obedient their child is in comparison to others. Not only are parents bowled over by the amazing triumphs their children accomplish, but they themselves are entering into new territory; the birth of their first child marks their entrance into parenthood. Although each subsequent child may be viewed as irreplaceable in his or her own right and undoubtedly draws out a specialized set of parenting skills, only the firstborn confers upon parents the illustriously distinguished titles of mother and father.

This extraordinary experience lends itself to the exceptional accomplishments enacted by firstborn children. In deference to Robert Merton's self-fulfilling prophecy, which suggests that people are capable of that which they believe they are capable of (1948), firstborns enter into situations at a higher starting point than their later-born peers. Equipped with the high levels of poise and self-assurance that their parents have instilled since their inception, and reeling from the positivity that parents themselves are experiencing from their newly donned parental identities, firstborns face the world with confident leadership skills, and an unfailingly steadfast work ethic. In other words, parents set the bar exceedingly high for firstborns, who in turn rise to the occasion academically (Iacovou, 2007; Wenner, 2007). Moreover, the fact that firstborns receive so much one-on-one stimulation from their parents contributes toward a high verbal prowess (Westerlund & Lagerberg, 2008) and mature demeanor (Families and Intellect, 1976; Zajonc, 2001; Zajonc & Markus, 1975), both of which translate quite propitiously into a classroom setting.

Benefits of One-on-One Parenting

Mothers and fathers of firstborns tend to be hyper-vigilant about their parental duties (Forer, 1969), even prior to the delivery of their beloved offspring. Expectant parents peruse through bookstores to thoroughly research the latest childrearing books that review up-to-date "do's and don'ts" associated with healthy, happy children, while households are impeccably transformed to comply with child safety standards. The methodical, systematic parenting style that parents of firstborns employ often transcends to their child, and it is not surprising that firstborns excel in academic environments, where regimented discipline equates with high levels of success.

Kirton's theory suggests that there are two types of cognitive styles that people possess: adaptive, in which firstborns excel, and innovative, mastered by later-borns (Skinner & Fox-Francoueur, 2010). Adaptors prefer to work in a structured, scheduled, rule-oriented milieu, whereas innovators feel stifled by such planned orderliness, and instead prosper under more flexible, creative, outside-the-box parameters. This knowledge may revolutionize our understanding of birth order and intelligence, since most IQ tests and educational environments investigate students' abilities against the backdrop of the adaptor's norms. Perhaps this is the reason why firstborns score three points higher on standardized tests compared with later-borns (Janecka, 2010), which may reflect the biased nature of the tests in terms of intellect.

The intoxicating high that firstborns experience, alas, comes to an end once a younger sibling graces the family unit with a very noticeable presence (Dunn & Kendrick, 1980; Dunn, Kendrick, & MacNamee, 1981; Field & Reite, 1984; Kendrick & Dunn, 1982). The birth of the second child can cause an uncomfortable jolt that upsets what the firstborn interprets as his sense of equilibrium, or the copious amounts of attention that had been lavished upon him or her. Nevertheless, the firstborn feels as though he has been "dethroned" and takes a while to adjust to the new sibling. This transitional period can be quite strenuous, for both the jealous firstborn, as well as exhausted parents who go to great lengths to reassure their first youngster while nurturing his or her younger newborn. The silver lining in this temporarily arduous cloud is that the situation tends to turn upward once the big brother/big sister role has fully been absorbed. Gripped with the knowledge that he or she is now the caretaker for the newest family member, the oldest, ideally, assumes such a role with gusto and eagerly takes the young sibling under his wing. The protective firstborn is thrust into the role of teacher/mentor. While on the surface this may appear to benefit the younger child, who has a built-in bodyguard and tutor, the actual beneficiary is the firstborn, whose cerebral development becomes tremendously advanced when assuming this surrogate role (Zajonc, 2001).

Firstborns in School

In school, firstborns may gravitate toward positions that will allow them to demonstrate and refine their superb leadership skills (Jarrett, 2003), such as class president or the captain of the chess club, as well as activities like the debate team whereby they can exercise the enhanced verbal dexterity that they have cultivated since birth (Berglund, Eriksson, & Westerlund, 2005). And although a number of factors correlate with whether or not a person attends college, including socioeconomic status and parental education, Wark, Swanson, and Mack (1974) found a positive relationship between firstborn children and a desire to pursue post-secondary schooling. Once enrolled in a university, different behavioral patterns among the birth orders persist and contribute toward academic success or failure. For example, whereas binge drinking on college campuses have skyrocketed to outrageous proportions (Mitka, 2009), firstborn students are more abstemious and refrain from spiraling out of control (Laird & Shelton, 2006). Surely this conscientious sensibility advances their longstanding record of successful scholastic achievement.

The Only Child

The only child is essentially an eldest child who lacks subsequent siblings, and is oftentimes lumped into the same category as firstborns. However, there are marked differences that discern the two placements from each other. Namely, throughout the course of his or her life, the only child remains in an environment that consists primarily of adults, and therefore only occasionally modifies his language to accommodate younger audiences. Utilizing sophisticated vernacular and prudent mannerisms which model the adults in the household, the only child is indeed wise beyond years, a trait which has both pros and cons. The benefits include higher IQ scores and a learned comportment (Polit, Nuttal, & Nuttall, 1980; Travis & Kohli, 1995), while the shortcomings entail an inability to relate to same-age peers (DeKeukelaere, 2004) and failure to divulge in the lighthearted and frolicsome exuberance of childhood. Moreover, without the presence of youngsters, only children never have to develop the art of sharing material belongings or emotional attention (Shulan, Guiping, & Qicheng, 1986).

The Middle Child

The middle child's arrival into the world is quite different (Forer, 1969). More experienced parents now create less of a fuss about all the "firsts," in terms of first smile, step, and word; they are no longer "firsts" to seasoned parents. Whereas the eldest child received acclaim for even the smallest of advancements, the middle child deals with very different parents, who must now divide their attention equitably among two children. Hence, the middle child is never able to relish in the undivided adoration that the eldest initially received. Although it might be assumed that the middle child would not fret about a lifestyle he never knew, this second-class status nevertheless seems to haunt his existence, and deep down he pities himself for being the overlooked and underappreciated runner-up. Parents of middle-born children have to cater to two children who are (at least theoretically) different in temperament. Feeling spread thin and often overwhelmed, second-time parents are more physically, emotionally, and mentally drained, and less apt to make overzealous aggrandizements toward their second-born child. Consequently, it is not uncommon for the middle child to become aware of and disgruntled at the lack of parental attention (Fritz, 2006).

Gender Dynamics

According to Hertwig, Davis, & Sulloway (2002), a U-shaped equity heuristic exists to describe parental investment, which suggests that mothers and fathers devote the majority of their energy to the eldest and youngest children. The firstborn is showered with praise because of his dutiful fulfillment of parental expectations, whereas the baby of the family symbolizes the fact his parent's reproductive window of time is about to expire and he therefore embodies their evolutionary "last chance" (Rhode et al., 2003). As is the case with all birth order patterns, gender plays a part in how the dynamics transpire (Harris & Morrow, 1992; Kristensen & Bjerkedal, 2010). According to the U-shaped equity heuristic, the middle child syndrome may be exacerbated or relieved based on whether or not that child replicates the gender configuration. For example, if the gender sequence of a family of three children follows a male-male-female or female-female-male arrangement, then the points of the "U" become reinforced. This is because both the firstborn and the lastborn represent the parent's novel experience in rearing a boy and a girl for the first time. Parents need to be aware of unbalanced treatment they may unconsciously afford their middle children, for it is well substantiated that parental involvement and school success parallel each other extensively (Barnard, 2004; Ray & Smith, 2010).

The Middle Child in School

Financially speaking, the strain of having a second child naturally further depletes family resources (Beld, 2006), which results in hand-me-down attire and understated, less showy or used playthings. Furthermore, parents are generally lackadaisical about the potential hazards associated with raising a child, as they were able to glean insight from the firstborn into the resourceful resilience that accompanies childhood (Colburn & Sorenson, 2010). Whereas firstborns were ushered to the hospital with minor scrapes, cuts, bruises, and coughs, parents assume a more relaxed stance about monitoring both safety concerns as well as staying atop everyday transactions such as bedtime readings, homework help, and quality time. This more relaxed attitude trickles down and eventually permeates the middle child's temperament; they are...

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