Spatial trends of fertility rates in Finland between 1980 and 2014

Recent research has shown that in many Western countries fertility rates are highest in suburban areas and lower in urban and rural areas. Here, we illustrate the changing patterns of spatial fertility in Finland between 1980 and 2014. Fertility in Finland started conforming the high suburban pattern during the 1990’s. This interestingly predates the first large scale urban sprawl (i.e., positive net migration in suburban areas) in the first decade of the 21st century in Finland

Faster Transition to the Second Child in late 20th Century Finland: A Study of Birth Intervals

Birth intervals are known to influence child and parental health and wellbeing, yet studies on the recent development of birth intervals in contemporary developed societies are scarce. We used individual-level representative register data from Finland (N=26,120; 54% women) to study the first interbirth interval of singleton births in cohorts born in 1955, 1960, 1965, 1970, and 1975. In women, the average interbirth interval has shortened by 7.8 months and in men by 6.2 months between the cohorts of 1955 and 1975. A higher age at first birth was associated with shorter birth intervals (in women, b = -1.68, p<.001; in men, b = -1.77, p<.001 months per year). Educational level moderated the effect of age at first on the first birth interval in both sexes. Due to rising ages at first birth in developed societies and the manifold ramifications of shorter birth intervals, this topic deserves more scholarly attention and studies from other countries

On the evolution of personality : Insights from contemporary Western humans

Recently, personality variation has been found to be associated with number of offspring, pace of reproduction, and other components of fitness in humans and other animals. The link between personality and fitness has inspired a surge of theoretical accounts on the evolution of personality. However, the associations between personality and fitness are yet to be sufficiently empirically elaborated for the theoretical advances to be solidly based. This thesis explores the pathways between personality and fertility in three contemporary Western human populations. Specifically, this thesis i) provides further evidence on the phenotypic associations between personality and lifetime reproductive success; ii) examines the differences between a phenotypic and genetic approach to natural selection on personality; iii) investigates whether personality is involved in a trade-off between the number and quality of offspring; and iv) explores possible novel selection pressures on personality. The results are discussed in relation to the theoretical accounts on the evolution of personality. The results suggest that the phenotypic associations between personality and lifetime reproductive success vary by populations. Further, it seems that the phenotypic and genetic approaches to natural selection on personality differ and that modern environments can impose novel selection pressures on personality. Lastly, it seems that personality is similarly associated with number of children and grandchildren, implying no quality quantity trade-offs in modern environments. Crucially, the results show that personality is not associated with fitness in any one way, or because of any one evolutionary mechanism. Further, the results suggest that the behavioural personality differences might not be evolutionarily relevant, but that personality correlates genetically with something else that affects fitness. Thus, future studies should concentrate on the individual personality traits and their genetic correlates, as trying to find a unified evolutionary answer for personality may prove an elusive task.Persoonallisuuden vaihtelun on viimeaikoina havaittu olevan yhteydessä jälkeläisten lukumäärään ja muihin kelpoisuuden tekijöihin niin ihmisillä kuin muillakin eläimillä. Persoonallisuuden ja kelpoisuuden välinen yhteys on synnyttänyt paljon teoreettista tutkimusta, jossa pohditaan persoonallisuuden evoluutiota. Tämä teoreettinen pohdinta tarvitsee tuekseen kuitenkin yksityiskohtaisempaa empiiristä tietoa, jota on tällä hetkellä niukasti saatavilla. Tämä väitöskirjatutkimus tarkastelee ja tarkentaa sitä, miksi ja millaisilla tavoilla persoonallisuus ja lasten lukumäärä ovat yhteydessä. Osatutkimukset on toteutettu kolmella länsimaisella aikalaisaineistolla Suomesta, Isosta-Britanniasta ja Yhdysvalloista. Tarkemmin keskitytään i) vertailemaan persoonallisuuden ja lasten lukumäärän välisiä geneettisiä ja ilmiasun tason yhteyksiä; ii) tutkimaan liittyykö persoonallisuuteen vaihtokauppaa jälkeläisten määrän ja laadun välillä; sekä iii) tarkastelemaan, luoko moderni länsimainen ympäristö uusia valintapaineita persoonallisuudelle. Näiden tutkimuskysymysten tuloksia arvioidaan suhteessa persoonallisuuden evoluutiota käsittelevään teoreettiseen kirjallisuuteen. Persoonallisuuden ja syntyvyyden väliset ilmiasun tason yhteydet vaihtelivat osatutkimuksesta toiseen ja geneettisen tason yhteydet eivät olleet samanlaisia kuin ilmiasun tason yhteydet. Näyttäisi myös siltä että nyky-ympäristöt luovat uudenlaisia valintapaineita persoonallisuudelle. Lisäksi persoonallisuus oli samalla tavalla yhteydessä niin lasten kuin lastenlastenkin lukumäärään. Tämä viittaa siihen, että persoonallisuuteen liittyen vaihtokauppaa lasten lukumäärän ja laadun välillä ei ole. Tämän väitöskirjatutkimuksen perusteella vaikuttaa siltä, että eri persoonallisuuspiirteet ovat yhteydessä kelpoisuuteen hyvin eri tavoin. On lisäksi mahdollista, että persoonallisuuserot eivät käyttäytymisen tasolla ole evolutiivisesti merkittäviä, vaan persoonallisuus korreloi geneettisesti joidenkin muiden kelpoisuuteen vaikuttavien tekijöiden kanssa. Tutkimuksen tulisikin tulevaisuudessa keskittyä yksittäisiin persoonallisuuspiirteisiin ja niiden geneettiseen taustaan, sillä yhtä evolutiivista selitystä persoonallisuudelle tuskin tullaan löytämään

The first Generations and Gender Survey in Finland: data collection and data quality

The first Generations and Gender Survey in Finland was collected in 2021/2022 as a web-based survey. In addition to the standard GGS-questionnaire, the Finnish survey included two new modules: the Miller Instrument, which captures childbearing motivations, and Global uncertainties, which enquires about perceptions of future threats. To further advance research on family dynamics, data from GGS Finland is linked to administrative records. This allows researchers to explore employment and family trajectories until 2026. Analyses of core socio-demographic characteristics and well-established fertility indicators reveal that the sample, by and large, represents the target population

The Company You Keep : Personality and Friendship Characteristics

Studies on personality and friendship have focused on similarities between friends, while differences in friendship patterns have received less attention. We used data from the British Household Panel Survey data (N = 12,098) to investigate how people's personalities are related to various characteristics of their three closest friends. All personality traits of the five-factor model were associated with several friendship characteristics with effect sizes corresponding to correlations between .06 and .09. Openness was especially prominent and idiosyncratic; individuals with high (vs. low) openness were about 3% more likely to have friends who live further away, are of the opposite sex and another ethnicity, and whom they meet less often. Agreeableness and extroversion were related to more traditional friendship ties. Individuals with high agreeableness had known their friends for a longer time, lived close to them, and had more "stay-at-homes" among their friends.Peer reviewe

Shorter birth intervals between siblings are associated with increased risk of parental divorce

Birth intervals are a crucial component of fertility behaviour and family planning. Short birth intervals are associated—although not necessarily causally—with negative health-related outcomes, but less is known about their associations with family functioning. Here, the associations between birth intervals and marital stability were investigated by Cox regression using a nationally representative, register-based sample of individuals with two (N = 42,481) or three (N = 22,514) children from contemporary Finland (observation period 1972–2009). Shorter interbirth intervals were associated with an increased risk of parental divorce over a ten-year follow-up. Individuals with birth intervals of up to 1.5 years had 24–49 per cent higher divorce risk compared to individuals whose children were born more than 4 years apart. The pattern was similar in all socioeconomic groups and among individuals with earlier and later entry to parenthood. Our results add to the growing body of research showing associations between short birth intervals and negative outcomes in health and family functioning.Peer reviewe

Social Resources are Associated With Higher Fertility Intentions in Contemporary Finland

Lower childbearing intentions can stem from a lack of social resources. However, not only actual but also perceived social support might signal that parents and parents-to-be will not be alone after having a child. Using register and GGS-Finland data from 2021-22, we investigate how emotional and instrumental support received from parents and other social network members, as well as a person’s subjective feeling that their social network is sufficient (measured as the absence of loneliness), are associated with fertility intentions. Logistic regression models reveal that receiving instrumental support - especially financial support - from parents and other relatives (but not non-kin) is associated with higher childbearing intentions. Not feeling lonely is also associated with higher childbearing intentions, particularly among individuals aged 26-30 years. Gender and partnership status nuance these associations. We conclude that social resources - indicated by both perceived and received support - shape childbearing intentions for those approaching or in prime childbearing age. The lack of perceived social resources among young adults may contribute to relatively low fertility, even in a high-income country with generous family policies such as Finland

Counting on parents or others? The role of social support for fertility intentions in Finland

This study explores the associations between receiving social support from network members other than individuals’ parents and fertility intentions in Finland. It additionally examines whether support from others can compensate for the lack of parental support or complement their support. Using logistic regression models applied to Generations and Gender Survey (GGS) data on individuals aged 18–45 years enriched with administrative registers, we found that Finns who received instrumental support from others were more likely to intend to have a child. Support from others did not compensate for, nor complement, a lack of parental support or parental geographic remoteness. However, among men with at least one parent deceased or unknown, those receiving emotional support from others were more likely to intend to have a child within three years (and as likely as individuals with both parents alive) than those not receiving this support, suggesting a compensatory mechanism

The first Generations and Gender Survey in Finland

The first Generations and Gender Survey in Finland was collected in 2021/2022 as a web-based survey. In addition to the standard GGS-questionnaire, the Finnish survey included two new modules: the Miller Instrument, which captures childbearing motivations, and Global uncertainties, which enquires about perceptions of future threats. To further advance research on family dynamics, data from GGS Finland is linked to administrative records. This allows researchers to explore employment and family trajectories until 2026. Analyses of core socio-demographic characteristics and well-established fertility indicators reveal that the sample, by and large, represents the target population