Discriminative Grandparental Solicitude: Evolution and Culture

This entry was written by Martha Gledhill-Tuite as part of a project done in BIAN 2133 ‘Human Reproductive Strategies’ at The Australian National University in 2019 Semester 2.


“Discriminative grandparental solicitude” (DGS) is the phenomenon of grandparents providing unequal care between their grandchildren (Euler & Weitzel, 1996). Many studies have found that maternal grandmothers (MGMs) deliver the most care to grandchildren, followed by maternal grandfathers (MGFs), paternal grandmothers (PGMs) and finally paternal grandfathers (PGFs). Most of these studies, however, have been conducted on developed Western countries. Evolutionary theory has been utilised to explain DGS, and research provides support for this, however theories of cultural differences are also supported by literature. Some argue that these two viewpoints are opposing, but a more holistic view is that they both interact to influence DGS. Nevertheless, it is beneficial to view the evidence behind the individual explanations.

Main Text

Paternity Certainty

DGS can be understood from an evolutionary perspective with a theory of parental certainty, first employed by Euler and Weitzel (1996). Grandparental care can greatly benefit parents and grandchildren, but also the grandparents themselves, as they are aiding in the continuation of their own genetic material. This is only advantageous, however, if the grandparents are genetically related to the grandchildren. MGMs have the highest grandparental certainty, as they know they are genetically related to their daughter and subsequently to her children, so they provide the most amount of care. At the other end of the spectrum are PGFs, who have two degrees of parental uncertainty: between their self and their son, and between their son and their grandchild. In the same article, Euler and Weitzel (1996) conducted a study in which they asked participants to retrospectively rank the level of care received by their grandparents while growing up. As hypothesised, MGMs supplied the most care and PGFs supplied the least. Surprisingly, MGFs were ranked more highly than PGMs for grandparental care, but this can be accounted for by exposure due to the MGM’s provision of care; MGFs who were separated from their partners contributed significantly less care. It was also hypothesised that grandparents would rely on resemblance to their grandchild as an indicator of genetic relation when there is less parental certainty. This is a behaviour observed in males with their children. The results indeed highlighted a correlation between resemblance and grandparental care, predominantly in MGFs and PGFs, indicating that parental certainty is a relevant factor. This article established the parental certainty explanation for DGS. The results of the study are consistent with this theory.

Preferential Investment in More Certain Kin

More recently, Danielsbacka, Tanskanen, Jokela and Rotkirch (2011) worked on an extension to the parental uncertainty theory of DGS. Titled “preferential investment in more certain kin” (PIMCK), it also considers ecological and situational factors. The theory suggests, for example, that if a grandmother has daughters and sons, she will provide less care for her son’s children than that of a MGF for his daughter’s children, because of preferential treatment. The study aimed to test this theory by surveying grandparents across Europe, and controlled for variables such as distance from grandchildren, health and partnership status. The results confirmed the same order of DGS as the article by Euler and Weitzel (1996), but also exhibited the trend predicted by PIMCK. If the PGM also had grandchildren via a daughter, she provided less care to her son’s children than the MGF who had only daughters. If the PGM only had sons, the care of the PGM and the MGF were equal. These results suit only an evolutionary explanation. This study indicates that parental certainty is a foundation of DGS, but it is also impacted by certain situational factors, to further increase the evolutionary effectiveness of caregiving.

Matrilineal Family Ties

The other lens through which DGS can be viewed focuses on cultural differences. Pashos and McBurney (2008) argue that DGS is due to strong cultural matrilateral family ties. This causes caregiving to be given and received more on the maternal side of the family. The study interviewed participants about the amount of care they received from grandparents, uncles and aunts, and their closeness to those family members. The participant’s parents were also asked about their closeness to the same family members. They discovered that aunts were more likely to provide care than uncles, regardless of whether they were paternal or maternal. This contradicts the parental uncertainty theory, as uncles and aunts from the same side of the family are equally related to their nieces and nephews and have the same level of familial certainty. They also determined that parental closeness with family members was correlated with care from those members, especially for the MGM and aunts. The authors claim that this supports their theory, however, it is also possible that high provision of care causes the parent to feel closer to those family members. Regardless, the results of this study shed doubt on the parental certainty justification for DGS, and provide some support for an explanation based on cultural influences.

Cultural Value of Relationships

Another study discussing cultural reasons for DGS was by Kaptijn, Thomese, Liefbroer and Silverstein (2013). They used surveys from 2375 Dutch grandparents in the Netherlands and 4026 Chinese grandparents in the rural Anhui province. For the Dutch participants, the usual trend was observed, with grandparents devoting more care to the children of their daughter than the children of their son. The authors suggest that these results could be due to the importance placed on mother-daughter relationships in Dutch culture. Contrarily, Chinese grandparents provided more care to their sons’ children than to their daughters’. Chinese culture values sons significantly more than daughters, which was the suggested reason as to why Chinese grandparents would provide more support to them. The patrilineal culture means that grandchildren are more likely to reside with their paternal grandparents, so this might cause paternal grandparents to take more care of these grandchildren, however the results remained the same when distance within the same village was controlled for. Observing a non-Western culture is important because it provides a better idea of how culture also affects phenomenon. This study proves that culture does, at least partly, define grandparental care.


Despite being a phenomenon observed in numerous cultures, the reasons behind DGS are unclear. Some suggest an evolutionary, parental certainty theory while others argue for cultural theories valuing certain relationships. Evidence supports both sides of the argument, indicating that these factors interact to determine the amount of care that grandparents choose to deliver. That being said, culture and evolution are intrinsically related, with evolution often being a determinate of culture. It seems that, in this case, they are so entwined that is unlikely for one to influence DGS without the other.

Literature Cited

Danielsbacka, M., Tanskanen, A. O., Jokela, M., & Rotkirch, A. (2011). Grandparental child care in Europe: Evidence for preferential investment in more certain kin. Evolutionary Psychology, 9(1), 3-24. .
Euler, H. A., & Weitzel, B. (1996). Discriminative grandparental solicitude as reproductive strategy. Hu Nat, 7(1), 39-59.
Kaptijn, R., Thomese, F., Liefbroer, A. C., & Silverstein, M. (2013). Testing evolutionary theories of discriminative grandparental investment. Journal of Biosocial Science, 45(3), 289-310.
Pashos, A., & McBurney, D. H. (2008). Kin relationships and the caregiving biases of grandparents, aunts, and uncles. Human nature, 19(3), 311-330.

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