Recent Selection for Behavioral Traits

Objectives of the proposed Research:
1) To test for and measure secular trends for a range of traits in humans, with a focus on behavioral and health traits.

2) To test whether the strength and direction of these trends changes between generations.

3) To test hypothesized mediators, including age at first birth and SES.

Study design and Analysis Plan: Using cohorts that have completed their fertility we will run regressions with the fertility rate as the dependent variable and polygenic scores as the independent variable. From this we will calculate the selection differential and the strength of selection, after adjusting for the missing variance of the polygenic scores. We will test the role of different moderators by splitting the sample according to the moderators. Analyses will be done and reported with and without the use of sampling weights. We intend to study selection of a range of behavioral and health related traits including the Big Five personality traits, occupational status, ADHD, BMI, educational attainment, cognitive performance, smoking cessation, smoking initiation, height, schizophrenia, depression and autism. We will derive our own polygenic scores from available summary statistics, not limiting ourselves to what is available in the Polygenic Score Data provided by HRS.

Secondary analyses will include: 1) measuring change in the polygenic scores between cohorts, with a focus on the difference between those born before, during and after the Second World War. 2) Estimate genotypic change using phenotypes available in the HRS that are closest to our genotypic traits, which include the Big Five personality traits, occupational status, ADHD, BMI, educational attainment, cognitive performance, smoking cessation, smoking initiation, height, schizophrenia, depression and autism.

We will not collaborate with researchers from other institutions.

Many traits affect and are associated with the number of children we have. Illnesses and education can get in the way of reproduction, for example. This results in our culture, society and environment selecting for certain traits in future generations. Although the speed of this process is extremely slow, its direction and exact strength is unclear for many traits. We would like to measure this effect.