Results The occurrence of giving financial help to a sibling and receiving financial help from a sibling in the sample

1. Childlessness and Financial Transfers between SiblingsThomas V. Pollet (T.V.Pollet@ncl.ac.uk)Biological Sciences, University of LiverpoolandSchool of Biology, University of Newcastle upon Tyne • Introduction • In modern societies, the proportion of individuals who remain childless is rising.1 It has been argued that childlessness thoroughly affects family and social relationships in modern societies. • Following kin selection theory, Essock-Vitale and McGuire (1985) analyzed helping behaviour. They found that childless women were more likely than mothers to give help to their nieces and nephews.2 Yet, it was also found that childless women were more likely than mothers to receive help from their nieces/nephews. They suggested that childless individuals could act as ‘helpers at the nest’. • In our research, we investigated whether childlessness affects financial help between siblings in a modern society. Childlessness is predicted to influence the financial relationships between siblings, even while controlling for social and other aspects of the sibling relationship. • Methods • The first data wave of the Netherlands Kinship Panel Study dataset was obtained through the Netherlands Interdisciplinary Demographic Institute (NIDI). The sampling procedure, survey questions and variables are extensively described by Dykstra and colleagues (2004).3 • Forty years is assumed to be more or less the age past which reproduction is not possible, therefore we selected all individuals in the dataset aged forty or over. Individuals were coded as childless, if they did not have children by any means (including adoption) and stated they did not want children in the future, in the case of men. Respondents were surveyed about their relationship with a randomly selected sibling. • The following variables were selected and/or constructed as predictor variables for ‘financial help given’ and ‘financial help received’: genetic relatedness (full versus adopted or half-sibling), childlessness, sibling childlessness, education level, interest given in the sibling’s personal life over the past three months (not at all/once or twice/several times), interest received(same categories), conflict (same categories), financial balance (I give more/equal/other gives more), initiative of contact (respondent takes initiative/equal/sibling takes initiative to contact the other), financial help given/received (have you given/received a substantial amount of money or valuables to/from sibling over the past year? If not used as dependent), age, age difference between siblings (in birth years), sex respondent, sex sibling and number of (full) living siblings. • Forward stepwise logistic regression was used to investigate which of the above predictors influences the likelihood of giving (or receiving from) money/valuables to a sibling.4 Here, we report only the significant predictor variables, model fits and odds ratios for relevant variables. • Results • The occurrence of giving financial help to a sibling and receiving financial help from a sibling in the sample was quite low (both below 2% ). • Childlessness, number of living siblings (less likely if more siblings), interest given and initiative of contact(more likely if other shows initiative/interest) were significant predictors of the likelihood of giving money or valuables to a sibling (model: -2LogLikelihood (-2LL)= 535.43; χ²= 44.77; df=6; p<0.001; Nagelkerke R²= 0.08; n= 4305). The other variables do not independently influence the likelihood of giving to a sibling. Childless individuals are 2.62 times more likely than ‘parents’ to have given financial help to their sibling (Wald=11.34; p= 7.58·10-4). This while controlling for the effects of the other proposed variables. • Age difference (more likely if larger age difference) , childlessness of sibling, number of living siblings (less likely if more siblings) , childlessness, interest received (more likely if more interest was shown)were significant predictors of the likelihood of receiving money or valuables from a sibling (model: -2LL= 374.06; χ²= 32.51; df=6; p<0.001; Nagelkerke R²= 0.08; n= 4305). Childless individuals are 2,41 times more likely than ‘parents’ to have received financial help to their sibling (Wald= 6.04; p= 0.014). If the respondent’s sibling is childless, he or she is 2.41 times more likely to receive money or valuables than when his/her sibling has children (Wald= 4.36; p= 0.037). Both effects were found while controlling for the effects of the other proposed variables. 2.62 times more likely to give money/valuables if childless • 2.14 times more likely to give money/valuables if childless • 2.41 times more likely to receive money/valuables if childless • Genetic relatedness did not (independently) affect financial transfers between siblings. This can be explained, however, by the finding that siblings who are not fully related interact significantly less. As such, genetic relatedness is likely to influence, financial relationships between siblings in an indirect way, via lower social interaction. • The majority of all financial relationships between siblings can be described as ‘not given and not received’. If we examine only the cases where a ‘financial transfer’ did occur, nearly 60% of all the financial relationships can be described as ‘given but not received’ (n= 87). There are no significant differences between parents and the ‘childless’, if a financial transfer did occur (χ²= 0.164; df= 2; p= 0.923). • Discussion • Childlessness affects the likelihood of giving and receiving ‘financial help’ to/from a sibling. This finding is similar to the results found by Essock-Vitale and McGuire (1985). This suggests that childlessness is an important factor for helping behaviour amongst kin in modern societies. • Yet, our study is unable to determine the actual fitness consequences of these differences between childless individuals and parents in giving and receiving money or valuables. • Further research is necessary to investigate the effects of childlessness on financial aspects of kin and social relationships. Preliminary study of friendship relations shows that childless individuals are also significantly more likely to give money or valuables to their friends. Although often neglected, the trade off between investments in children and investments in other social and kin relations might be an important aspect for the study of the evolution of cooperation and altruism. Conclusion • Childless individuals are significantly more likely to give a substantial amount of money or valuables. Yet, childless individuals are also more likely receive money or valuables from their sibling. • In modern societies childlessness thoroughly affects the financial relationships between siblings, even while controlling for important social characteristics of the relationship. Yet, further research is necessary to investigate the importance and the possible fitness consequences of this phenomenon. References/acknowledgements • McAllister F. & Clarke L. (1998). Choosing Childlessness, London: Family Policy Studies Centre.; DeOllos I.Y. & Kapinus C.A. (2002). Aging childless individuals and couples: Suggestions for new directions of research, in Sociological Inquiry,72: 72-80.; Park K. (2005). Choosing Childlessness: Weber’s Typology of Action and Motives of the Voluntarily Childless, in Sociological Inquiry, 75: 372-402. • Essock-Vitale S.M. & McGuire M.T. (1985). Women’s lives viewed from an evolutionary perspective. II. Patterns of helping, in Ethology and Sociobiology, 6: 155-173. • Dykstra P.A., Kalmijn M., Knijn T.C.M., Komter A. E., Liefbroer A.C. & Mulder C.H. (2004). Codebook of the Netherlands Kinship Panel Study, a multi-actor, multi-method panel study on solidarity in family relationships, Wave 1. NKPS Working Paper No. 1, The Hague: Netherlands Interdisciplinary Demographic Institute. • Pampel F. C. (2000). Logistic regression: A primer, Quantitative Applications in the Social Sciences Series #132, Thousand Oaks: Sage Publications. Acknowledgements: Iwould like to thank NIDI for access to the data and the members of the evolutionary psychology research group at the University of Liverpool, as well as the other Msc. Students, for their comments. The research presented here is part of my MSc. thesis at the University of Liverpool. ‘The Netherlands Kinship Panel Study is funded by grant 480-10-009 from the Major Investments Fund of the Netherlands Organization for Scientific Research (NWO), and by the Netherlands Interdisciplinary Demographic Institute (NIDI), Utrecht University, the University of Amsterdam and Tilburg University’ RESPONDENT SIBLING