This article explores the inverse relationship between the net effect of birth order and educational attainment. Later-born children were shown to spend longer in education and attain higher qualifications, however this was attributed to the educational expansion that took place in 20th century Sweden, in conjunction with longer average birth intervals within large sibships. This supports my hypothesis, where in the absence of such educational expansion, first-borns tend to succeed more in education due to increased parental investment, compared to later-born children.
Dong, H, Manfredini, M, Kurosu, S, Yang, W & Lee, JZ 2017, 'Kin and birth order effects on male child mortality: three East Asian populations, 1716–1945', Evolution and human behavior, vol. 38, no. 2, pp. 208-216. Available from: https://doi.org/10.1016/j.evolhumbehav.2016.10.001. [5 September 2019]
This study analysed the allocation of parental investment as being crucial in child survival outcomes within three East Asian populations (1716-1945). It was concluded that although parental investment is essential for all offspring, it is more beneficial for first-borns in the long term compared to later-born children. This notion underpins my hypothesis whereby increased parental investment in older siblings is often perceived as being advantageous for the whole family.
Ekman, J, Eggers, S & Griesser, M 2002, 'Fighting to stay: the role of sibling rivalry for delayed dispersal', Animal Behaviour, vol. 64, no. 3, pp. 453-459. Available from: https://doi.org/10.1006/anbe.2002.3075. [5 September 2019]
This article studied the relationship between sibling rivalry and delayed dispersal among the Siberian jays. This pertains to my study where in controlling for sex, sibling rivalry was seen to precede early dispersal, resulting from within-brood competition for resources. However, it was also found that delayed dispersal was more common among this species, due to the benefits that may be gained from remaining in the natal home.
Ekman, J, Baglione, V, Eggers, S & Griesser, M 2001, 'DELAYED DISPERSAL: LIVING UNDER THE REIGN OF NEPOTISTIC PARENTS', The Auk, vol. 118, no. 1, pp. 1-10, 10. Available from: https://doi.org/10.1642/0004-8038(2001)118[0001:DDLUTR]2.0.CO;2. [5 September 2019]
This article explores parental nepotism and the concession of resources to selected offspring as an inclusive fitness gain, wherein the underlying power dynamics among large sibships, can impact the allocation of parental investment and inheritance of resources. It was concluded that offspring often delay dispersal if their natal territory offers more inheritable resources and therefore increases their chances of survival. This notion underpins my study, whereby children may choose to leave their natal home earlier if they can inherit or acquire better resources elsewhere.
Ginja, R, Jans, J & Karimi, A 2017, 'Parental investments in early life and child outcomes evidence from swedish parental leave rules'. Available from: https://ssrn.com/abstract=3069449. [5 September 2019]
This study analysed parental investment outcomes among offspring in Sweden. Parental investment was measured in terms of time spent with offspring and monetary resources available. This study highlights the importance of disposable income, wherein higher-income mothers were shown to invest more in first-born children, which in conjunction with my hypothesis, leads to improved educational outcomes, compared to later-born children.
Hayami, A 1983, 'The myth of primogeniture and impartible inheritance in Tokugawa Japan', Journal of Family History, vol. 8, no. 1, pp. 3-29. Available from: https://doi.org/10.1177%2F036319908300800101. [5 September 2019]
This article investigates the impartible inheritance of resources based on birth order within the Japanese village of Nishijo (1773-1869). The study first highlighted how primogeniture was not always sex-biased, wherein many households were being headed by women. In addition to this, it was proposed that ultimogeniture ultimately delayed the age at which the household could be inherited by succeeding generations and therefore was more prevalent in higher socioeconomic areas.
Koenig, WD, Pitelka, FA, Carmen, WJ, Mumme, RL & Stanback, MT 1992, 'The evolution of delayed dispersal in cooperative breeders', The Quarterly review of biology, vol. 67, no. 2, pp. 111-150. Available from: https://doi.org/10.1086/417552. [5 September 2019]
This article examines the delayed-dispersal threshold model as a guide in analysing the costs and benefits associated with delayed dispersal among cooperative breeders. The study highlighted a multitude of ecological factors influencing dispersal, including population density and spatiotemporal variations in territory quality, all of which can be linked to the impact of number of siblings and parental investment on offspring dispersal.
Low, BS & Clarke, AL 1991, 'Family Patterns in Nineteenth-Century Sweden: Impact Of Occupational Status and Landownership', Journal of Family History, vol. 16, no. 2, pp. 117-138. Available from: https://journals.sagepub.com/doi/abs/10.1177/036319909101600202. [6 September 2019]
This article investigates the impact of resources on family patterns, through analysing the occupational status, land ownership, legitimacy and parity of individuals in 1800s Sweden. It was found that birth order had a significant effect on accessibility and acquisition of resources, which pertains to my study as it emphasises how resource competition between siblings can impact dispersal from natal home.
Mulder, MB 1998, 'Brothers and sisters', Human Nature, vol. 9, no. 2, pp. 119-161. Available from: https://doi.org/10.1007/s12110-998-1001-6. [6 September 2019]
Parental investment can often be measured in terms of educational attainment and resource and property inheritance. In testing the Trivers-Willard hypothesis, it was found that educational investment in daughters from the Kipsigis of Kenya, was greater among poor families. Although this study focuses on sex-biased investment, it also illustrates how allocation of parental investment among offspring in large sibships can either result in competition or cooperation.
Nitsch, A, Lummaa, V & Faurie, C 2016, 'Sibship effects on dispersal behaviour in a pre‐industrial human population', Journal of evolutionary biology, vol. 29, no. 10, pp. 1986-1998. Available from: https://doi.org/10.5061/dryad.jt03g. [5 September 2019]
This article focuses on the pivotal role sibship plays in dispersal within a Finnish population. It was revealed that limited access to land resources was the main cause of early dispersal among males, whereas competition over access to wealthy mates was the major cause of dispersal among females. Despite sex differences, these findings pertain to my study by highlighting the crucial role of sibling interactions in causing early dispersal from natal home.
Pollet, TV, Dijkstra, P, Barelds, DP & Buunk, AP 2010, 'Birth order and the dominance aspect of extraversion: Are firstborns more extraverted, in the sense of being dominant, than laterborns?', Journal of Research in Personality, vol. 44, no. 6, pp. 742-745. Available from: https://doi.org/10.1016/j.jrp.2010.10.002. [6 September 2019]
Early dispersal from natal home can often be influenced by an early acquisition of independence, resulting from increased parental investment. First-born children often experience increased parental investment during early stages of life, due to the absence of sibling competition. However, in controlling for age and sibship size among 1500 participants, this study found later born children to be more extraverted and dominant than first-borns. This highlights how independence can be influenced by social attitudes and personality, which may delay dispersal.
Towner, MC 2001, 'Linking dispersal and resources in humans', Human Nature, vol. 12, no. 4, pp. 321-349. Available from: https://doi.org/10.1007/s12110-001-1002-1. [5 September 2019]
This article investigates the interplay between offspring dispersal and resource acquisition, through examining age at dispersal, birth order, sex and father's social status and wealth in individuals from Oakham, Massachusetts (1750-1850). It was concluded that birth order and number of siblings were not significantly associated with early dispersal. Therefore, this study highlights the importance in controlling for sex, when discerning whether birth order and subsequent parental investment impacts dispersal from natal home.