This article was part of BIOC14H3 S, 2026 at the University of Toronto Scarborough Campus
Authors: Daisy Bright-McKee, Gayeon Mun and Andrew Ahmed

All psychological traits show significant and substantial genetic influence

All psychological and behavioural traits have a strong and substantial genetic factor, as outlined by researchers Robert Plomin and his colleagues in 2015. They conducted a review of meta-analyses that show how traits ranging from personality, to intelligence (and everything in between) is strongly associated with genetics, and this finding has been consistently replicated study after study.

In the article, researchers analyzed twin studies, adoption data, and GCTA (Genome-Wide Complex Trait Analysis), finding that intelligence, personality, mental health, and personal preferences are influenced by genetics. For example, in the domain of psychopathology, 14 twin studies of schizophrenia showed monozygotic concordance rates of about 50% and dizygotic concordances of about 15%. This confirms that genetic factors significantly influence individual differences in psychological traits.

Replication is important in genetic research, because it rules out methodological errors, or statistical anomalies.This also helps researchers see how the hypothesis works across cultures, different samples and methodologies. The ability to reproduce the results of a study is important to address the reliability and reproducibility across diverse populations.

Based off of the article cited below:
Plomin, R., DeFries, J. C., Knopik, V. S., & Neiderhiser, J. M. (2016). Top 10 replicated findings from behavioral genetics. Perspectives on Psychological Science, 11(1), 3–23. https://doi.org/10.1177/1745691615617439

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