First Partner Choice in a Native Minority: The Role of Own and Parental Ethnolinguistic Affiliation.

Despite increasing diversity within many societies, ethnically endogamous unions remain common. In contexts where one ethnic minority has lived alongside the majority for centuries, understanding who partners with whom is central to understanding how ethnic boundaries are maintained or dissolved. This study examines the role of own and parental ethnolinguistic affiliation for the first partner choice in Finland.

A matter of time: Bateman's principles and mating success as count and duration across social strata in contemporary Finland.

Bateman's principles heavily influence the understanding of human reproductive behaviour. Yet, few rigorous studies on Bateman's principles in contemporary industrialized populations exist. Most studies use small samples, exclude non-marital unions, and disregard recent insights on within-population heterogeneity in mating strategies.

Less Is More? Repartnering and Completed Cohort Fertility in Finland.

An extensive literature theorizes the role of repartnering for cohort fertility and whether union dissolution can be an engine for fertility. A large share of higher order unions are nonmarital cohabitations, but most previous studies on completed cohort fertility have analyzed only marital unions, and none have incorporated nonmarital cohabitations using population-level data. To analyze the relationship between the number of unions and cohort fertility for men and women, we use Poisson regression with Finnish register data to enumerate every birth, marriage, and cohabitation among the 1969-1972 birth cohorts at ages 18-46.

Adult sex ratios: causes of variation and implications for animal and human societies.

Converging lines of inquiry from across the social and biological sciences target the adult sex ratio (ASR; the proportion of males in the adult population) as a fundamental population-level determinant of behavior. The ASR, which indicates the relative number of potential mates to competitors in a population, frames the selective arena for competition, mate choice, and social interactions. Here we review a growing literature, focusing on methodological developments that sharpen knowledge of the demographic variables underlying ASR variation, experiments that enhance understanding of the consequences of ASR imbalance across societies, and phylogenetic analyses that provide novel insights into social evolution.

Parental age gaps among immigrants and their descendants: Adaptation across time and generations?

Age gaps between partners have undergone dramatic changes in high-income countries over the past century. Yet, there has been little focus on age gaps for immigrants and their descendants. This is an important omission because age gaps can be interpreted as a macro-level indicator of intergenerational adaptation.

Higher divorce risk when mates are plentiful? Evidence from Denmark.

Work from social and biological sciences has shown that adult sex ratios are associated with relationship behaviours. When partners are abundant, opportunities for mate switching may increase and relationship stability decrease. To date, most of the human literature has used regional areas at various levels of aggregation to define partner markets.

Unemployment, intragenerational social mobility and mortality in Finland: heterogeneity by age and economic context.

Background: We explore how mortality is related to unemployment and intragenerational social mobility in Finland. Unemployment and social mobility are two labour market experiences that are largely studied separately, despite the fact that selection processes into unemployment and downward mobility are intertwined. Because both causal and health selection mechanisms may vary depending on the timing of these experiences, we consider heterogeneity by age and economic context.

Health behaviour, extrinsic risks, and the exceptions to the rule.

Pepper & Nettle make a compelling case for how evolutionary thinking can help explain behaviours that cluster with deprivation. The role of extrinsic mortality risk in driving behaviour is probably important, but strong evidence is still lacking. By thinking carefully about behaviours seemingly at odds with an evolutionary life history perspective, we can gain important insights that will help refine theory.

Adult sex ratio and social status predict mating and parenting strategies in Northern Ireland.

Evidence from animal species indicates that a male-biased adult sex ratio (ASR) can lead to higher levels of male parental investment and that there is heterogeneity in behavioural responses to mate scarcity depending on mate value. In humans, however, there is little consistent evidence of the effect of the ASR on pair-bond stability and parental investment and even less of how it varies by an individual's mate value. In this paper we use detailed census data from Northern Ireland to test the association between the ASR and pair-bond stability and parental investment by social status (education and social class) as a proxy for mate value.

Knowing your neighbourhood: local ecology and personal experience predict neighbourhood perceptions in Belfast, Northern Ireland.

Evolutionary theory predicts that humans should adjust their life-history strategies in response to local ecological threats and opportunities in order to maximize their reproductive success. Cues representing threats to individuals' lives and health in modern, Western societies may come in the form of local ages at death, morbidity rate and crime rate in their local area, whereas the adult sex ratio represents a measure of the competition for reproductive partners. These characteristics are believed to have a strong influence over a wide range of behaviours, but whether they are accurately perceived has not been robustly tested.

Parental investment in child health in sub-Saharan Africa: a cross-national study of health-seeking behaviour.

Parents face trade-offs between investing in child health and other fitness enhancing activities. In humans, parental investment theory has mostly been examined through the analysis of differential child outcomes, with less emphasis on the actions parents take to further a particular offspring's condition. Here, we make use of household data on health-seeking for children in a high mortality context where such behaviours are crucial for offspring survival.

Effects of local extrinsic mortality rate, crime and sex ratio on preventable death in Northern Ireland.

Background And Objectives: Individual investment in health varies greatly within populations and results in significant differences in the risk of preventable death. Life history theory predicts that individuals should alter their investment in health (somatic maintenance) in response to ecological cues that shift the perceived fitness payoffs to such investments. However, previous research has failed to isolate the effects of different ecological factors on preventable death, and has often relied on macro-level data without individual controls.

Someone to live for: effects of partner and dependent children on preventable death in a population wide sample from Northern Ireland.

How to allocate resources between somatic maintenance and reproduction in a manner that maximizes inclusive fitness is a fundamental challenge for all organisms. Life history theory predicts that effort put into somatic maintenance (health) should vary with sex, mating and parenting status because men and women have different costs of reproduction, and because life transitions such as family formation alter the fitness payoffs from investing in current versus future reproduction. However, few tests of how such life history parameters influence behaviours closely linked to survival exist.