Childlessness and Genetic Relatedness

Their Influence on Sibling Ties in a Post-Industrial Society

Thomas Pollet

Msc. in Evolutionary Psychology
(September 2005)

Liverpool: School of biological sciences

Promotor: Prof. Dr. ?????

Abstract: “In this study we investigate the effects of childlessness and genetic relatedness on sibling relationships in a post-industrial society. Our analyses show that childless individuals are significantly more likely to have a very good relationship with their siblings than parents. Moreover, fully related siblings significantly have better relationships with their siblings than adopted or half-siblings. Childlessness and genetic relatedness were also found to have significant effects on other sibling relationship characteristics. Results are discussed with reference to inclusive fitness theory and individualization theory.”

Acknowledgements

1. Introduction

2. Individualization, childlessness and social relations

    2.1 Individualization

    2.2 Childlessness and concomitant characteristics

3. Inclusive fitness and adaptive decision making

4. Social factors and quality of relationship

5. Research questions and aims of the study

6. NKPS-Dataset and methodology

    6.1 The NKPS dataset and the selected variables

    6.2 Preliminary analyses (HOMALS)

    6.3 Multinomial logistic regression (MLR)

7. Results from analyses of NKPS

    7.1 MLR (main effects) for quality of relationship

    7.2 Discussion of MLR for relationship quality

        7.2.1 Variable selection

        7.2.2 Comparison good versus very good relationship

    7.3 MLR with interaction effects for relationship quality

    7.4 MLR for ‘investment measures’ of relationships

        7.4.1 Giving interest

        7.4.2 Receiving interest

        7.4.3 Giving and receiving interest

        7.4.4 Initiative contact

        7.4.5 Financial balance

        7.4.6 Giving financial help

        7.4.7 Receiving financial help

        7.4.8 Giving and/or receiving financial help

    7.5 Voluntary and involuntary childlessness and sibling relationships

8. General discussion and limitations of the study

    8.1 General discussion

    8.2 Limitations and further research

9. Conclusion

10. References

Appendix