Skip to content
Modern WisdomModern Wisdom

How Do Genes Influence Our Behaviour? - Robert Plomin | Modern Wisdom Podcast 353

Robert Plomin, is a psychologist, geneticist and an author. Separating the influence of nature and nurture is something everyone considers. Robert is the 71st most cited psychologist of the 20th century and has run the largest and most clinically detailed twin and adoption studies in history to finally provide definitive answers to these fundamental questions. Expect to learn how much of who we are can be attributed to our environment and how much was predisposed by our genetics, why parenting doesn't make a difference, why the choice of school your child goes to only impacts 1% of their outcomes, whether penis size is heritable, if there is a gay gene or not and much more... Sponsors: Get 20% discount on Reebok’s entire range including the amazing Nano X1 at https://geni.us/modernwisdom (use code MW20) Get 10% discount on your first month from BetterHelp at https://betterhelp.com/modernwisdom (discount automatically applied) Extra Stuff: Buy Blueprint - https://amzn.to/3f2OYYk Get my free Ultimate Life Hacks List to 10x your daily productivity → https://chriswillx.com/lifehacks/ To support me on Patreon (thank you): https://www.patreon.com/modernwisdom #behaviouralgenetics #twinstudies #naturevsnurture - 00:00 Intro 01:42 What are Behavioural Genetics? 04:22 Nature & Nurture 17:52 How Genetics Are Studied 22:39 Biggest Ever Twin Study 27:39 Do Genes Influence Behaviour & Health? 36:32 Heritability of Different Traits 50:09 Seeking Happiness 55:57 Heritability of Sexual Preference 58:41 Do Children Behave Like Their Parents? 1:03:22 Non-Genetic Impacts on Behaviour 1:09:54 Educating Children on Genetics 1:23:38 DNA Dating 1:29:51 Increasing Equality of Opportunity 1:35:08 Living With Acceptance of Genetics 1:39:49 Where to Find Robert - Listen to all episodes online. Search "Modern Wisdom" on any Podcast App or click here: Apple Podcasts: https://apple.co/2MNqIgw Spotify: https://spoti.fi/2LSimPn Stitcher: https://www.stitcher.com/podcast/modern-wisdom - Get in touch in the comments below or head to... Instagram: https://www.instagram.com/chriswillx Twitter: https://www.twitter.com/chriswillx Email: https://chriswillx.com/contact/

Robert PlominguestChris Williamsonhost
Aug 1, 20211h 42mWatch on YouTube ↗

At a glance

WHAT IT’S REALLY ABOUT

Genes Shape Our Minds: Why DNA Dominates Behavior More Than Parenting

  1. Behavioral geneticist Robert Plomin explains that around 50% of individual differences in psychological traits (IQ, personality, mental health, educational achievement) are due to inherited DNA, with many physical traits even more heritable.
  2. Contrary to traditional psychology and popular belief, shared family environment (parenting style, home, school quality) explains surprisingly little of these differences; instead, non‑shared, largely chance experiences and genetic propensities dominate.
  3. Most traits are influenced not by single “genes for X” but by thousands of tiny genetic variants that create probabilistic risks and appetites, which then guide how people select and shape their environments over time.
  4. Plomin argues this view is both unsettling and liberating: parents matter emotionally but don’t control outcomes as much as they think, individuals are best served by working with their genetic grain, and policy should focus on equality of opportunity rather than equality of outcome.

IDEAS WORTH REMEMBERING

5 ideas

Roughly half of psychological differences between people are genetic in origin.

Across thousands of twin and adoption studies worldwide, traits like IQ, personality, mental health, and educational achievement average about 50% heritability, meaning inherited DNA differences explain about half of the variation between individuals.

Shared family environment has far less impact than most people think.

Adoptive siblings raised together resemble each other almost not at all on IQ and many psychological traits, indicating that simply growing up in the same home with the same parents does not systematically make children more similar.

Most traits are polygenic and probabilistic, not driven by single “genes for X.”

Common traits and disorders (obesity, depression, reading ability, schizophrenia) are influenced by thousands of small genetic variants, which confer risk or propensity rather than guarantee; this shifts the picture from hard determinism to statistical likelihoods.

Highly heritable does not mean unchangeable at the individual level.

Heritability describes differences in a population, not what is possible for any one person; for example, weight is about 70% heritable, yet individuals can still gain or lose weight through diet and behavior, albeit with different levels of difficulty.

“Disorders” like dyslexia or schizophrenia sit on continuous dimensions.

Genetic evidence suggests that there are no natural cut‑off points separating the “ill” from the “normal”; instead, everyone carries some risk variants, and diagnoses are arbitrary thresholds on underlying quantitative traits.

WORDS WORTH SAVING

5 quotes

DNA isn’t all that matters, but it matters more than anything else, and it matters more than everything else put together in determining who we are.

— Robert Plomin

Parents matter, but they don’t make a difference.

— Robert Plomin

The fact of growing up in the same family isn’t making [adoptive siblings] similar.

— Robert Plomin

There are no disorders, there are just quantitative dimensions.

— Robert Plomin

Ability will out.

— Robert Plomin (quoting Francis Galton)

Definition and scope of behavioral genetics (individual differences vs human universals)Heritability of traits: IQ, weight, personality, mental health, happiness, education, sexualityMisconceptions about genes: determinism, “genes for X”, and the medical model of disordersTwin and adoption studies, polygenic scores, and the DNA revolutionShared vs non‑shared environment: why parenting and school effects are smaller than assumedImplications for parenting, education, meritocracy, and social policyPersonal agency, chance events, and living in line with genetic propensities

High quality AI-generated summary created from speaker-labeled transcript.

Get more out of YouTube videos.

High quality summaries for YouTube videos. Accurate transcripts to search & find moments. Powered by ChatGPT & Claude AI.

Add to Chrome