Genetic and Phenotypic Associations of the Polygenic Score of Delay Discounting and Life History Traits

Objectives
Delay discounting reflects individual differences in future orientation and impulsivity and may relate to life-history strategies. Because delay discounting has a substantial genetic basis, we investigated whether the polygenic score (PGS) for delay discounting is associated with genetic predispositions for key life-history traits—education, age at first birth, and number of children—and whether these relationships are reflected phenotypically.

Methods
We used data from the Wisconsin Longitudinal Study, including 2713 men and 2980 women of European ancestry with available genetic data. Linear regressions examined associations between the delay-discounting PGS and PGSs for educational attainment, age at first birth, and number of children. Parallel models assessed phenotypic associations with years of postsecondary education, age at first birth, and number of children. All models controlled for birth year and the first 10 genomic principal components.

Results
In both sexes, the delay-discounting PGS was strongly negatively associated with the PGSs for educational attainment and age at first birth, and positively associated with the PGS for number of children. Phenotypic associations were directionally consistent but substantially smaller: higher delay-discounting PGSs predicted fewer years of education, earlier first birth, and (marginally) more children. Explained variance ranged from approximately 4%–5% for education to 1%–2% for reproductive traits.

Conclusion
Genetic and phenotypic associations between delay discounting, education, and reproductive timing align with predictions from fast–slow life-history theory. These findings suggest that behavioral tendencies related to impulsivity and future orientation share molecular genetic foundations with key life-history traits while leaving substantial scope for environmental influences.