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Birth order

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Birth order

  1. 1. Birth Order: History, Debate, and Current Research Brooke Schauder, PhD Erie Psychology Consortium Pacific Graduate School of Psychology
  2. 2. How it all began? <ul><li>Francis Galton “English Men of Science: Their Nature and Nurture” </li></ul><ul><li>Traced lives of 180 “eminent” men </li></ul><ul><li>Revealed that 48% were firstborn or only sons. </li></ul>
  3. 3. Classic Studies <ul><li>Altus, (1962) </li></ul><ul><ul><li>Firstborn male college students scored higher on verbal abilities than later born. </li></ul></ul><ul><li>Altus, et al., (1965) </li></ul><ul><ul><li>Birth order of students entering college at UC, Santa Barbara between 1960 and 1936 – over 60% were firstborn. </li></ul></ul>
  4. 4. Classics <ul><li>Belmont & Marolla, (1973) </li></ul><ul><ul><li>386,114 Dutch men </li></ul></ul><ul><ul><li>Data from Raven Progressive Matrices test </li></ul></ul><ul><ul><li>Chilren from large families had poorer performance </li></ul></ul><ul><ul><li>Firstborns scored better and gradient of declining scores with birth order </li></ul></ul><ul><li>Goertzel, Goertzel, & Goertzel, (1978) </li></ul><ul><ul><li>314 eminent 20 th century individuals </li></ul></ul><ul><ul><li>46% were firstborn </li></ul></ul>
  5. 5. Past to Present <ul><li>Clark & Rice, (1982): Firstborns are overrepresented among Nobel Laureates. </li></ul><ul><li>Terry, (1989): Firstborns are overrepresented among prominent psychologists. </li></ul><ul><li>Armor, (2001): Examined data from over 2,000 families - 3 point difference between first and second born, 2 point difference between second and third born on scores of Peabody Picture Vocabulary Test. </li></ul>
  6. 6. The Hypotheses <ul><li>The Admixture Hypothesis </li></ul><ul><li>Page & Grandon (1979): Parental IQ, SES, etc. may be responsible for both large families and low IQ, causing cross-sectional data to appear to support birth order effects. </li></ul>
  7. 7. Resource Dilution Model <ul><li>Blake, 1981: Parental Resources are Limited. With each sibling, attention, money, etc., must be further divided – diluting or decreasing the amount each sibling has. </li></ul>
  8. 8. Confluence Model <ul><li>Zajonc & Markus (1975): </li></ul><ul><ul><li>Firstborns are exposed to more adult language and attention in general. Laterborns are exposed to less mature speech and behavior, leading to less maturity with each additional sibling. </li></ul></ul><ul><ul><li>Firstborns have the experience of tutoring, often being called upon to be “surrogate parents” therefore enhancing intellectual ability. </li></ul></ul><ul><ul><li>Therefore, the confluence model predicts a negative influence of birth order for children less than 11 and positive for those over 11 years. </li></ul></ul>
  9. 9. Family Size <ul><li>Large family size correlates with lower IQ (Rodgers, et al., 2000). </li></ul><ul><li>“ Results of the analysis of the NLSY data support the belief the low-IQ parents make large families and are inconsistent with the belief that large families make low-IQ children.” </li></ul>
  10. 10. Cross Sectional vs. Longitudinal <ul><li>Cross sectional studies tend to find significant birth order effects, particularly with IQ (Belmont & Marolla, 1973). </li></ul><ul><li>Within family studies usually demonstrate no relationship between birth order and IQ (Berbaum & Moreland, 1980; Rodgers, et al., 2000). </li></ul>
  11. 11. Traits Vs. Intelligence <ul><li>Personality, in addition to or rather than intelligence, may vary by birth order (Simonton, 1999). </li></ul><ul><li>Conscientiousness and openness to experience may be much more important than IQ in terms of “eminence” (Sulloway, 1996). </li></ul>
  12. 12. Perfectionism <ul><li>Adler’s patterns: </li></ul><ul><li>Firstborn : striving for perfection and need to please </li></ul><ul><li>Middle : surrounded by competitors – peacemakers/arbitrators </li></ul><ul><li>Youngest : inferiority – need to overcome everyone </li></ul><ul><li>Only : center of attention/ atmosphere of parental anxiety </li></ul>
  13. 13. Ashby, et al., 2003 <ul><li>Study of 136 undergraduates completed Almost Perfect Scale – Revised (APSR) and PBOI. </li></ul><ul><li>- Categories of adaptive perfectionists, maladaptive perfectionists, and non-perfectionists differ according to birth order. </li></ul><ul><li>-Adaptive perfectionists were less likely to be middle children. </li></ul><ul><li>-Adaptive and maladaptive perfectionists had fewer characteristics of younger children than non-perfectionists. </li></ul><ul><li>-non-significant findings for oldest and only children </li></ul>
  14. 14. Cross-Cultural Research <ul><li>Educated older siblings may provide more intellectual stimulation for youngers than would uneducated parents in Asian and African immigrant populations (Davis, Cahan, and Bashi). </li></ul><ul><li>In a study of Kenyan adolescents, intelligence generally declined as birth order increased. However, 2 nd borns had higher IQ than first, attributed to demands facing firstborns (Munroe & Munroe, 1983). </li></ul>
  15. 15. (culture continued) <ul><li>Columbian study of over 36,000 college applicants did NOT support dilution or confluence models. In fact, ranking in test scores by birth order was 3,4,5,2,6,1. Only 1% of variability was explained by birth order and family size. Socioeconomic status was a much more powerful variable. </li></ul>
  16. 16. Culture and Status Attainment <ul><li>Marjoribanks, 2001 </li></ul><ul><li>180 Anglo-Australian, 88 Greek, & 72 Italian young adults </li></ul><ul><li>Longitudinal: data collected at age 11 (environmental influences on the family) </li></ul><ul><li>Follow-up collection 5 years later on aspirations </li></ul><ul><li>Data collection at 25 </li></ul><ul><li>For Italians, only family size was negatively correlated with status. </li></ul><ul><li>Birth order negatively correlated with status attainment for Anglo-Australians and Greeks (older had higher attainment). </li></ul>
  17. 17. Wisconsin Card Sort <ul><li>115 males and 104 females in grades 1-6 in Taiwan </li></ul><ul><li>Computerized WCST </li></ul><ul><li>No birth order effects found </li></ul>
  18. 18. (Culture Continued) <ul><li>Among a sample of Zimbabwean children, (511 boys and 632 girls), there was a general downward trend in IQ measures as birth order increased (Wilson, et al., 1990). </li></ul>
  19. 19. Epilepsy & Birth Order <ul><li>Obeid, et al., 2002: </li></ul><ul><ul><li>336 epileptics in Saudi Arabia </li></ul></ul><ul><ul><li>Large family size is very common </li></ul></ul><ul><ul><li>Mean family size is 6.8 </li></ul></ul><ul><ul><li>Low birth order (older siblings) significantly more likely to have seizure disorder. </li></ul></ul><ul><ul><li>Possibly due to prolonged labour in firstborns. </li></ul></ul>
  20. 20. Autism and Birth Order <ul><li>Spiker, et al., 2001 </li></ul><ul><li>144 Autism multiplex families </li></ul><ul><li>Used Autism Diagnostic Interview – Revised (ADI-R) </li></ul><ul><li>Lower nonverbal IQ for second born autistics / less than 50% of firstborns had nonverbal in ranges of retardation, but 70% of secondborns did. </li></ul><ul><li>Maternal antibodies and/or decreased parental attention </li></ul>
  21. 21. Lateral Preference and Birth Order <ul><li>The Left Hemispherehas a greater need for Oxygen than the right and therefore is more susceptible to oxygen deficiency (Liederman, 1983). </li></ul><ul><li>Therefore, children in either first born or later born positions are under more risk of undergoing trauma (Ernst & Angst, 1983). </li></ul><ul><li>Meta-analysis of studies on birth order, birth stress, and lateral preferences did not support relationship (Searleman, et al., 1989). </li></ul>
  22. 22. Lateral Preference & Birth order in Chimpanzees <ul><li>Hopkins & Dahl, 2000 </li></ul><ul><li>154 Chimpanzees, ranging from 3-57 years </li></ul><ul><li>Tube procedure </li></ul><ul><li>Results showed that birth order has significant effect on lateral preference in captive chimps. </li></ul><ul><li>Hormones’ effects on brain and/or trauma in first and laterborns </li></ul>
  23. 23. Sexual Preference and Birth Order <ul><li>“ With each older brother a male’s chances of being a homosexual increases by about 30% relative to a first born male.” </li></ul><ul><li>-Wickepedia </li></ul>
  24. 24. Blanchard, 1997 <ul><li>Homosexual men have a higher mean birth order than do comparable heterosexuals. </li></ul><ul><li>These results have been collected cross-culturally, in England, The Netherlands, Canada, and the US. </li></ul><ul><li>Results typically show that more older brothers, rather than sisters, is significant. </li></ul>
  25. 25. Fraternal Birth Order Effect <ul><li>Hypothesized mechanisms: “Maternal Immune response.” Supported in animal studies that maternal immune system may not recognize male hormones (Klassen, 1997). </li></ul>
  26. 26. Blanchard, 2004 <ul><li>“ Meta-analysis of aggregate data from 14 samples of 10,143 male subjects shows that homosexuality in human males is predicted by higher number of older brothers.” </li></ul><ul><li>Birth weight supports biological mechanisms. </li></ul><ul><li>Environmental theory that more older brothers increases odds of homosexual behavior. </li></ul>
  27. 27. Female Sexuality and Birth Order <ul><li>Bogaert, 1997 </li></ul><ul><li>Data on over 5,000 women was investigated. </li></ul><ul><li>No relationship between birth order and female homosexuality was found. </li></ul>
  28. 28. Bibliography <ul><li>Rodgers, Cleveland, Oord, & Rowe (2000). Resolving the debate over birth order, family size, and intelligence. American Psychologist, 55(6). </li></ul><ul><li>“ Birth Order” http://en. Wikipedia.org/wiki/Birth.order </li></ul><ul><li>Wilson, Mundy-Castle, & Panditji (1990). Birth order and intellectual development among zimbabwean children. Journal of Social Psychology, 130(3), 409-411. </li></ul><ul><li>Adams & Phillips (1972). Motivational and achievement differences among children of various ordinal birth positions. Child Development, 43, 155-164. </li></ul><ul><li>Velandia, Grandon, & Page (1978). Family size, birth order, and intelligence in a large South American sample. American Educational Research Journal, 15(3), 399-416. </li></ul>
  29. 29. (bibliography continued) <ul><li>Belmont & Marolla (1973). Birth order, family size, and intelligence. Science, 182, 1096-1101. </li></ul><ul><li>Galton, F (1874, 1895). English men of science: Their nature and nuture. New York: D. Appleton and Company. </li></ul><ul><li>Munroe & Munroe (1967). Birth order and intellectual performance in three East African Societies. Journal of Social Psychology, 123. </li></ul><ul><li>Altus, (1965). Birth order and academic primogeniture. Journal of Personality and Social Psychology, 2(6), 872-876. </li></ul><ul><li>Searleman, Porac, & Coren (1989). Relationship between birth order, birth stress, and lateral preferences: a critical review. Psychological Bulletin, 105(3), 397-408. </li></ul><ul><li>Ashby, LoCicero, & Kenny (2003). The relationship of multidimensional perfectionism to psychological birth order. Journal of Individual Psychology, 59(1). </li></ul>
  30. 30. (bibliography continued) <ul><li>Obeid, Awada, Amene, & Oni (2002). The controversy of birth order as a risk factor for epilepsy: a study from Saudi Arabia. Acta Neurol Scand, 105, 174-178. </li></ul><ul><li>Rodgers, (2001). What causes birth order – Intelligence patterns? The admixture hypothesis, revived. American Psychologist, 56(6-7), 505-510. </li></ul><ul><li>Shu, Tien, Lung, & Chang (2000). Norms for the Wisconsin Cart Sorting Test in 6 to 11 year old children in Taiwan. The Clinical Neuropsychologist, 14(3), 275-286. </li></ul><ul><li>Michalski & Shackelford, (2001). Comment: methodology, birth order, intelligence, and personaltiy. American Psychologist, 56(6-7), 520-524. </li></ul><ul><li>Marjoribanks (2001). Sibling correlates of young adults’ status attainment: ethnic group differences. Journal of Psychology, 123(5), 507-516. </li></ul><ul><li>Zajonc, (2001). The family dynamics of intellectual development. American Psychologist, 56(6-7), 490-496. </li></ul>
  31. 31. (bibliography continued) <ul><li>Spiker, Lotspeich, Dimiceli, Szatmari, Myers, & Risch, (2001). Birth order effects on nonverbal IQ scores in autism multiplex families. Journal of Autism and Developmental Disorders, 31(5). </li></ul><ul><li>Hopkins & Dahl (2000). Birth order and hand preference in chimpanzeees: implications pathological models of handedness in humans. Journal of Comparative Psychology, 114(3). </li></ul><ul><li>Bogaert, (1997). Birth order and sexual orientation in women. Behavioral Neuroscience, 111, 1395-1397. </li></ul><ul><li>Blanchard, (2004). Quantitative and theoretical analyses of the relation between older brothers and homosexuality in men. Journal of Theoretical Biology, 230, 173-187. </li></ul>

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