A ‘gendered Need’ Explanation Does Not Fully Explain Lineage Based Differences in Grandparental Investment Found in a Large British Cohort Study

Ghysels (2012) argues for a ‘gendered need’ explanation of lineage based differences in grandparental investment. Maternal grandmothers are subsidiary care-givers: only if mothers fail to fulfil this gender role, (maternal) grandmothers will step in. The SHARE data do indeed seem to support this explanation (though see Appendix). However, it is not at odds with an evolutionary explanation, such as paternity uncertainty theory. Paternity uncertainty theory suggests that matrilineal biases will emerge all else being equal (see Euler & Michalski, 2008, for review). If there are differences in need, then all else is not equal, and we should expect grandparents to respond accordingly. Following Ghysels, first the effect of parental workforce/employment status on differences in contact between maternal grandmother/father and paternal grandmother/ father was investigated (MGM vs. PGM and MGF vs. PGF) in the Millennium cohort sample (Hansen, 2006; Pollet et al., 2009). Lineage differences in the diversity of help offered were also examined (Pollet et al., 2009). As measures, current workforce status (parent currently in paid work: yes, no; ampjob00; appjob00) and employment status for those in work were used (current or most recent job: self-employed or employee; amemse00; apemse00). Due to space constraints, the baseline effects (without controls) are only shown graphically, and not the statistical models. Figure 1a does indeed show that parental workforce status attenuates some of the findings: if the mother is in work (vs. not), then the maternal side has relatively more frequent contact. Moreover, there is also an indication that if the father is currently working, the maternal side has relatively more contact than when the father is not.