Editing Sibling (section)

==Birth order==
{{Main|Birth order}}
[[File:P S Krøyer 1897 - Døtrene Benzon.jpg|thumb|upright|''The Benzon Daughters'' by [[Peder Severin Krøyer]]]]
[[File:Pedro II of Brazil and his sisters 1839.JPG|thumb|upright|Emperor [[Pedro II of Brazil]] with his sisters Princesses [[Princess Francisca of Brazil|Francisca]] and [[Princess Januária of Brazil|Januária]], 1839]]

Birth order is a person's rank by age among his or her siblings. Typically, researchers classify siblings as "eldest", "middle child", and "youngest" or simply distinguish between "first-born" and "later-born" children.

Birth order is commonly believed in [[pop psychology]] and popular culture to have a profound and lasting effect on psychological development and [[Personality psychology|personality]]. For example, firstborns are seen as conservative and high-achieving, middle children as natural mediators, and youngest children as charming and outgoing. Despite its lasting presence in the public domain, studies have failed to consistently produce clear, valid, compelling findings; therefore, it has earned the title of a [[Pseudoscience|pseudo-psychology]] amongst the scientific psychological community.<ref name="Psychology Around Us">{{cite book|last1=Comer|first1=Ronald|last2=Gould|first2=Elizabeth|last3=Ogden|first3=Nancy|last4=Boyes|first4=Michael|title=Psychology Around Us|url=https://archive.org/details/psychologyaround0000come|url-access=registration|date=February 2012|publisher=Wiley}}</ref>

===History===
The theorizing and study of birth order can be traced back to [[Francis Galton]]'s (1822–1911) theory of birth order and [[wikt:eminence|eminence]] and [[Alfred Adler]]'s (1870–1937) theory of birth order and personality characteristics.{{citation needed|date=June 2020}}

==== Galton ====
In his book ''English Men of Science: Their Nature and Nurture'' (1874), Galton noted that prominent composers and scientists are over-represented as first-borns.<ref name="intelltheory.com">{{cite web|last1=Esping|first1=Amber|title=Does Birth Order Affect Intelligence?|url=http://www.intelltheory.com/birthOrder.shtml|website=Human Intelligence|access-date=2014-11-15|archive-date=2020-02-14|archive-url=https://web.archive.org/web/20200214171030/http://www.intelltheory.com/birthOrder.shtml|url-status=dead}}</ref> He theorized three main reasons as to why first-borns are generally more eminent:
# [[Primogeniture]] laws: first-borns have access to their parents' financial resources to continue their education.<ref name="intelltheory.com"/>
# First-borns are given more responsibility than their younger siblings and are treated more as companions by their parents.<ref name="intelltheory.com"/>
# First-borns are given more attention and nourishment in families with limited financial resources.<ref name="intelltheory.com"/>

====Adler====
* First Borns: Fulfilling family roles of leadership and authority, obedient of protocol and hierarchy. Seek out and prefer order, structure and adherence to norms and rules. They partake in goal-striving behaviour as their lives are centred around achievement and accomplishment themes. They fear the loss of their position in the top of the hierarchy.<ref name="ReferenceA">{{cite journal|last1=Alan|first1=E.S.|title=Issues in Birth Order Research Methodology: Perspectives from Individual Psychology|journal=The Journal of Individual Psychology|date=2012|volume=68|issue=1|pages=75–106}}</ref>
* Middle Children: Feel like outcasts of families as they lack primacy of the first child and the "attention garnering recency" of the youngest. These children often go to great lengths to de-identify themselves with their siblings, in an attempt to make a different and individualized identity for themselves as they feel like they were "squeezed out" of their families.<ref name="ReferenceA"/>
* Youngest Children: Feel disadvantaged compared to older siblings, are often perceived as less capable or experienced and are therefore indulged and spoiled. Because of this, they are skilled in coaxing/charming others to do things for them or provide. This contributes to the image of them being popular and outgoing, as they engage in attention-seeking behaviour to meet their needs.<ref>{{cite journal|last1=Adler|first1=E.S.|title=Issues in Birth Order Research Methodology: Perspectives from Individual Psychology|journal=The Journal of Individual Psychology|date=2012|volume=68|issue=1}}</ref>

=== Contemporary findings ===
The flaws and inconsistencies in birth order research eliminate its validity. It is very difficult to control solely for factors related to birth order, and therefore most studies produce ambiguous results.<ref name="ReferenceA"/> Embedded into theories of birth order is a debate of nature versus nurture. It has been disproved that there is something innate in the position one is born into, and therefore creating a preset role. Birth order has no genetic basis.<ref>{{cite journal|last1=Wichman|first1=A.L.|last2=Rodgers|first2=J.L.|last3=MacCallum|first3=R.C.|title=A Multilevel Approach to the Relationship Between Birth Order and Intelligence|journal=Society for Personality and Social Psychology Inc|date=2006|volume=32|issue=1|pages=117–127|doi=10.1177/0146167205279581|pmid=16317193|s2cid=5791756}}</ref>

The social interaction that occurs as a result of birth order however is the most notable. Older siblings often become role models of behaviour, and younger siblings become learners and supervisees. Older siblings are at a developmental advantage both cognitively and socially. The role of birth order also depends greatly and varies greatly on family context. Family size, sibling identification, age gap, modeling, parenting techniques, gender, class, race, and temperament are all confounding variables that can influence behaviour and therefore perceived behaviour of specific birth categories.<ref>{{cite journal|last1=Eckstein|first1=D.|last2=Kaufman|first2=J.A.|title=The Role of Birth Order in Personality: An Enduring Intellectual Legacy of Alfred Adler|journal=The Journal of Individual Psychology|date=2012|volume=68|issue=1|pages=60–61}}</ref> The research on birth order does have stronger correlations, however, in areas such as intelligence and physical features, but are likely caused by other factors other than the actual position of birth. Some research has found that firstborn children have slightly higher [[IQ]]s on average than later born children.<ref>{{cite news |author=Carey, Benedict |url=http://www.iht.com/articles/2007/06/21/africa/siblings.php |title=Family dynamics, not biology, behind higher IQ |newspaper=International Herald Tribune |date=June 21, 2007 |access-date=July 15, 2007}}</ref> However, other research finds no such effect.<ref>Rodgers, J.L., Cleveland, H.H., van den Oord, E. and Rowe, D. (2000). Resolving the Debate Over Birth Order, Family Size and Intelligence. ''American Psychologist'', Vol. 55.</ref> It has been found that first-borns score three points higher compared to second borns and that children born earlier in a family are on average, taller and weigh more than those born later.<ref name="Psychology Around Us"/> However, it is impossible to generalize birth order characteristics and apply them universally to all individuals in that subgroup.

==== Contemporary explanations for IQ findings ====

===== Resource dilution model =====
(Blake, 1981) provide three potential reasons for the higher scoring of older siblings on IQ tests:<ref name="intelltheory.com"/>
# Parental resources are finite, first-born children get full and primary access to these resources.<ref name="intelltheory.com"/>
# As the number of a children in a family goes up, the more resources must be shared.<ref name="intelltheory.com"/>
# These parental resources have an important impact on a child's educational success.<ref name="intelltheory.com"/>

===== Confluence model =====
[[Robert Zajonc]] proposed that the intellectual environment within a family is ever-changing due to three factors, and therefore more permissive of first-born children's intellectual advancement:<ref name="intelltheory.com"/>
# Firstborns do not need to share parental attention and have their parents' complete absorption. More siblings in the family limit the attention devoted to each of them.<ref name="intelltheory.com"/>
# Firstborns are exposed to more adult language. Later-borns are exposed to the less-mature speech of their older siblings.<ref name="intelltheory.com"/>
# Firstborns and older siblings must answer questions and explain things to younger siblings, acting as tutors. This advances their cognitive processing of information and language skills.<ref name="intelltheory.com"/>

In 1996, interest in the science behind birth order was re-sparked when [[Frank Sulloway]]’s book ''Born To Rebel'' was published. In this book, Sulloway argues that firstborns are more conscientious, more socially dominant, less agreeable, and less open to new ideas compared to later-borns. While being seemingly empirical and academic, as many studies are cited throughout the book, it is still often criticized as a biased and incomplete account of the whole picture of siblings and birth order. Because it is a novel, the research and theories proposed throughout were not criticized and peer-reviewed by other academics before its release.<ref>{{cite journal|last1=Johnson|first1=Gary. R.|title=Science, Sulloway, and Birth Order: An Ordeal and an Assessment|journal=Politics and the Life Sciences|date=2000|volume=19|issue=2|pages=211–245|doi=10.1017/S0730938400014842|s2cid=233320874}}</ref>
[[Literature review]]s that have examined many studies and attempted to control for confounding variables tend to find minimal effects for birth order on personality.<ref>Ernst, C. & Angst, J. (1983). ''Birth order: Its influence on personality.'' Springer.</ref><ref>{{cite journal | last1 = Jefferson | first1 = T. | last2 = Herbst | first2 = J.H. | last3 = McCrae | first3 = R.R. | year = 1998 | title = Associations between birth order and personality traits: Evidence from self-reports and observer ratings | journal = Journal of Research in Personality | volume = 32 | issue = 4| pages = 498–509 | doi=10.1006/jrpe.1998.2233| url = https://zenodo.org/record/1229908 }}</ref>
In her review of the scientific literature, [[Judith Rich Harris]] suggests that birth order effects may exist within the context of the family of origin, but that they are not enduring aspects of personality.<ref>Harris, J.R. (1998). ''[[The Nurture Assumption]]: Why children turn out the way they do.'' New York: Free Press.</ref>

In practice, systematic birth order research is a challenge because it is difficult to control for all of the variables that are statistically related to birth order. For example, large families are generally lower in socioeconomic status than small families, so third-born children are more likely than first-born children to come from poorer families. Spacing of children, parenting style, and gender are additional variables to consider.