Grandparental investment: Past, present, and future

What motivates grandparents to their altruism? We review answers from evolutionary theory, sociology, and economics. Sometimes in direct conflict with each other, these accounts of grandparental investment exist side-by-side, with little or no theoretical integration. They all account for some of the data, and none account for all of it. We call for a more comprehensive theoretical framework of grandparental investment that addresses its proximate and ultimate causes, and its variability due to lineage, values, norms, institutions (e.g., inheritance laws), and social welfare regimes. This framework needs to take into account that the demographic shift to low fecundity and mortality in economically developed countries has profoundly altered basic parameters of grandparental investment. We then turn to the possible impact of grandparental acts of altruism, and examine whether benefits of grandparental care in industrialized societies may manifest in terms of less tangible dimensions, such as the grandchildren's cognitive and verbal ability, mental health, and well-being. Although grandparents in industrialized societies continue to invest substantial amounts of time and money in their grandchildren, we find a paucity of studies investigating the influence that this investment has on grandchildren in low-risk family contexts. Under circumstances of duress - for example, teenage pregnancy or maternal depression - there is converging evidence that grandparents can provide support that helps to safeguard their children and grandchildren against adverse risks. We conclude by discussing the role that grandparents could play in what has been referred to as Europe's demographic suicid

Toward an integrative framework of grandparental investment

This response outlines more reasons why we need the integrative framework of grandparental investments and intergenerational transfers that we advocated in the target article. We discusses obstacles - from misconceptions to poor measures - that stand in the way of such a framework and of a better understanding of the effects of grandparenting in the developed world. We highlight new research directions that have emerged from the commentaries, and we end by discussing some of the things in our target article about which we may have been wron

Predictors of grandparental investment decisions in contemporary Europe: Biological relatedness and beyond

Across human cultures, grandparents make a valued contribution to the health of their families and communities. Moreover, evidence is gathering that grandparents have a positive impact on the development of grandchildren in contemporary industrialized societies. A broad range of factors that influence the likelihood grandparents will invest in their grandchildren has been explored by disciplines as diverse as sociology, economics, psychology and evolutionary biology. To progress toward an encompassing framework, this study will include biological relatedness between grandparents and grandchildren, a factor central to some discipline\u27s theoretical frameworks (e.g., evolutionary biology), next to a wide range of other factors in an analysis of grandparental investment in contemporary Europe. This study draws on data collected in the Survey of Health, Ageing and Retirement in Europe from 11 European countries that included 22,967 grandparent-child dyads. Grandparents reported biological relatedness, and grandparental investment was measured as the frequency of informal childcare. Biological and non-biological grandparents differed significantly in a variety of individual, familial and area-level characteristics. Furthermore, many other economic, sociological, and psychological factors also influenced grandparental investment. When they were controlled, biological grandparents, relative to non-biological grandparents, were more likely to invest heavily, looking after their grandchildren almost daily or weekly. Paradoxically, however, they were also more likely to invest nothing at all. We discuss the methodological and theoretical implications of these findings across disciplines

Cross-cultural evidence does not support universal acceleration of puberty in father-absent households

Father absence in early life has been shown to be associated with accelerated reproductive development in girls. Evolutionary social scientists have proposed several adaptive hypotheses for this finding. Though there is variation in the detail of these hypotheses, they all assume that family environment in early life influences the development of life-history strategy, and, broadly, that early reproductive development is an adaptive response to father absence. Empirical evidence to support these hypotheses, however, has been derived from WEIRD (Western, Educated, Industrialized, Rich and Democratic) populations. Data from a much broader range of human societies are necessary in order to properly test adaptive hypotheses. Here, we review the empirical literature on father absence and puberty in both sexes, focusing on recent studies that have tested this association beyond the WEIRD world. We find that relationships between father absence and age at puberty are more varied in contexts beyond WEIRD societies, and when relationships beyond the father-daughter dyad are considered. This has implications for our understanding of how early-life environment is linked to life-history strategies, and for our understanding of pathways to adult health outcomes, given that early reproductive development may be linked to negative health outcomes in later life. This article is part of the theme issue \u27Developing differences: early-life effects and evolutionary medicine\u27

Interdisciplinary perspectives on grandparental investment: a journey towards causality

Why do grandparents invest so heavily in their grandchildren and what impact does this investment have on families? A multitude of factors influence the roles grandparents play in their families. Here, we present an interdisciplinary perspective of grandparenting incorporating theory and research from evolutionary biology, sociology and economics. Discriminative grandparental solicitude, biological relatedness and the impact of resource availability are three phenomena used to illustrate how these perspectives, within such a multi-level approach, add value by complementing not competing with each other. Changing demographics mean there is greater demand and opportunity for actively engaged grandparents to help their families, especially in times of need. Grandparents have been filling this emerging niche because in some societies the role of community and government never has, or increasingly cannot, meet the diverse needs of families. Built on an empirical foundation of descriptive and correlational research, grandparent research has rapidly entered a phase where the potential causal relationships between grandparents’ roles and family health, well-being and structure can be scrutinised. Together, these investigations are producing high-quality evidence that ultimately can support informed public policy and service delivery decisions. We finish by detailing two examples of such research efforts that highlight opportunities for future research

The combined role of sexual selection and socioeconomic environment in explaining everyday risk-taking behavior in human males

Sexual selection theory predicts that males, especially in their prime reproductive years, are more risk-prone than females. Risk-taking is a means to convey mate quality or “good genes” to members of the opposite sex or competitive ability to members of the same sex. Therefore, risk-taking should be more common in the presence of potential mates (intersexual selection or female choice) or in the presence of male competitors (intrasexual selection or male–male competition). Risk-taking can also be situated within a life history/ecological perspective, according to which environmental unpredictability promotes more present-oriented and risky behavioral strategies. Therefore, people living in areas of low socioeconomic status are predicted to be more risk-prone. We conducted an observational study on risk-taking in two everyday situations: crossing the road and riding a bicycle. A total of 1,030 participants, 906 road-crossers and 124 cyclists, were recorded at various intersections throughout Perth, Western Australia. In line with predictions from sexual selection, males were more likely to cross a road in high-risk conditions and to ride a bicycle without wearing a helmet. These behaviors were also most common in younger adult males. Female and male onlookers had no effect on male risk-taking, which suggests that norm adherence is a more powerful force than sexual selection in shaping risk-related behaviors. Area-level socioeconomic status was strongly associated with the frequency of risk-taking, implying that environmental stressors can affect risk attitude. Elucidating the ultimate drivers behind everyday risk-taking has important practical implications for risk intervention strategies. The results of an observational study show that young males were the demographic group that was most likely to take risks in everyday situation (crossing the road and riding a bicycle). We also found that people in socioeconomically disadvantaged areas engaged in risk-taking more frequently than people in areas of higher socioeconomic status. (PsycInfo Database Record (c) 2024 APA, all rights reserved

The role of mating effort and co-residence history in step-grandparental investment

The prevalence of divorce in both parental and grandparental generations has led to a rise in the number of children who now have families that include both biological and step-grandparents. Despite the thorough examination of biological grandparents\u27 contributions in the recent literature, there remains a scarcity of studies focusing on the investment of step-grandparents. Using population-based data from a sample of 2494 parents in Germany, we assessed grandparental investment through financial support and assistance with childcare of grandparents (N = 4238) and step-grandparents (N = 486). The study revealed that step-grandparents provided lower levels of investment in their grandchildren compared with biological grandparents. Furthermore, the study identified that a longer duration of co-residence between step-grandparents and parents earlier in life did not correspond to an increase or decrease in step-grandparental investment. However, investment by separated biological grandparents increased with the increasing length of co-residence with parents. In line with the scarce literature on step-grandparental investment, these findings indicate that mating effort may be the most important motivation for step-grandparental investment

Birthweight and paternal involvement predict early reproduction in British women: Evidence from the National Child Development Study

There is considerable interest in the mechanisms maintaining early reproduction in the most socioeconomically disadvantaged groups in developed countries. Previous research has suggested that differential exposure to early-life factors such as low birthweight and lack of paternal involvement during childhood may be relevant. Here, we used longitudinal data on the female cohort members from the UK National Child Development Study (n=3014-4482 depending upon variables analysed) to investigate predictors of early reproduction. Our main outcome measures were having a child by age 20, and stating at age 16 an intended age of reproduction of 20 years or lower. Low paternal involvement during childhood was associated with increased likelihood of early reproduction (O.R. 1.79-2.25) and increased likelihood of early intended reproduction (O.R. 1.38-2.50). Low birthweight for gestational age also increased the odds of early reproduction (O.R. for each additional s.d. 0.88) and early intended reproduction (O.R. for each additional s.d. 0.81). Intended early reproduction strongly predicted actual early reproduction (O.R. 5.39, 95% CI 3.71-7.83). The results suggest that early-life factors such as low birthweight for gestational age, and low paternal involvement during childhood, may affect women’s reproductive development, leading to earlier target and achieved ages for reproduction. Differential exposure to these factors may be part of the reason that early fertility persists in socioeconomically disadvantaged groups. We discuss our results with respect to the kinds of interventions likely to affect the rate of teen pregnancy

Keeping the family: A socio-ecological perspective on the challenges of child removal and reunification for mothers who have experienced substance-related harms

The challenges and experiences associated with child removal and reunification from the perspective of mothers experiencing substance-related harms is under-researched in Australia. Our qualitative study employed a socio-ecological model to better understand the background to child removal, and perceived barriers and facilitators to achieving reunification of mother and child. In-depth interviews were conducted with 16 women, 8 of whom self-identified as Australian First Nations People. At the time of the interviews, these women were either living in substance use rehabilitation facilities, their own home or with relatives. Findings highlighted a history of complex disadvantage and trauma among the women, along with a deep and enduring commitment to their children. Key barriers to reunification included limited social support networks, insecure housing, and challenges in meeting conflicting requirements from the child protection, social welfare and justice systems. An important facilitator to reunification was access to a residential substance use rehabilitation facility that offered holistic wrap-around services with links to community support. This study highlights the inadequacy of individual approaches focused on parents’ substance use and emphasises the need to address significant structural disadvantages that underpin increasing numbers of children being placed in government mandated care in Australia

Investment by maternal grandmother buffers children against the impacts of adverse early life experiences

Exogenous shocks during sensitive periods of development can have long-lasting effects on adult phenotypes including behavior, survival and reproduction. Cooperative breeding, such as grandparental care in humans and some other mammal species, is believed to have evolved partly in order to cope with challenging environments. Nevertheless, studies addressing whether grandparental investment can buffer the development of grandchildren from multiple adversities early in life are few and have provided mixed results, perhaps owing to difficulties drawing causal inferences from non-experimental data. Using population-based data of English and Welsh adolescents (sample size ranging from 817 to 1197), we examined whether grandparental investment reduces emotional and behavioral problems in children resulting from facing multiple adverse early life experiences (AELEs), by employing instrumental variable regression in a Bayesian structural equation modeling framework to better justify causal interpretations of the results. When children had faced multiple AELEs, the investment of maternal grandmothers reduced, but could not fully erase, their emotional and behavioral problems. No such result was observed in the case of the investment of other grandparent types. These findings indicate that in adverse environmental conditions the investment of maternal grandmothers can improve child wellbeing