Stability and Malleability of Biological and Psychological Traits Over the Course of 6 Decades

• In Event: The Relevance of Typical and At-Risk Development for Adult Outcomes

Abstract

Mental abilities and physical growth are important determinants of health across the lifespan (e.g., Deary, Hill & Gale, 2021; Fontana & Hu, 2014). In the endeavor to improve health, it is crucial to understand the patterns of stability and malleability of such biological and psychological traits across development as this can provide information about opportunities for positive health impacts. Comprehensive long-term longitudinal studies provide the necessary data to describe the differential patterns of trait stability across the lifespan. The current study set out to investigate the stability of mental abilities and physical growth over the course of 6 decades from infancy into mid-to-older adulthood. It was hypothesized that biological traits such as height and weight are more stable overall compared to psychological traits such as mental abilities, and that the timing of the greatest stability differs between all three traits.

The data originates from a long-term longitudinal study initiated in 1954. A cohort of 450 infants born into families representative for the region where the study was conducted was enrolled at birth. The physical, motor, mental and social health and development of these infants was then monitored repeatedly until young adulthood. Since 2019, 60% of the surviving members of this cohort participated in a follow-up assessment on health and well-being when they were between 58 and 67 years old. Mental abilities, height, and weight were assessed at 11 time-points between 6 months and 65 years of age. Standardized instruments, such as the Brunet-Lézine Scale of Psychomotor Development of Children (Brunet & Lézine, 1951) and the Stanford-Binet Test of Intelligence (Terman & Merrill, 1937) estimated mental abilities. Height was assessed in the supine position in infancy and in the standing position thereafter, and weight was measured in a weighing pan or on a beam balance. For the analyses described here, all individuals with less than 25% missing data were included (N = 281) and incomplete data were imputed.

Bivariate cross-time correlations showed that for mental abilities, stability coefficients with age-65 mental abilities increased from negligible-to-small in infancy and preschool age (r = .09-.44) to large in childhood and adolescence (r = .51-.63). For growth measures, stability coefficients with age-65 growth measures were uniform across development, with height being highly stable from infancy to 65-years of age (r = .64-.77) and weight small-to-moderately so (r = .28-.41; Figure 1). When a latent model was used, despite differences in timing, the overall stability of mental abilities approached that of weight (r = .24-.63, Figure 2).

The findings indicate that stability and malleability across development differ between biological and psychological traits, namely, physical growth and mental abilities. This requires consideration in interventions targeting these traits as facilitators for improving health outcomes. The potential role of gene-environment correlation (e.g., Briley & Tucker-Drob, 2017; Sauce & Matzel, 2018; Tucker-Drob & Briley, 2014) in explaining the different stability patterns across the lifespan will be discussed, and the findings will be expanded to a cohort of individuals at biological risk, namely those born preterm.

Authors

• Dominique A Eichelberger, University Children's Hospital Zurich

• Fabio Sticca, Marie Meierhofer Institut für das Kind

• Dinah R Kuebler, University Children's Hospital Zurich

• Tanja Kakebeeke, University Children's Hospital Zurich

• Jon A Caflisch, University Children's Hospital Zurich

• Oskar G. Jenni, University Children’s Hospital

• Flavia M Wehrle, University Children's Hospital Zurich
  Presenting Author