Citing research, Sam Harris finds it humbling how little control parents have over their children's character. He states that for most psychological traits, the breakdown is roughly 50% genetic and 50% environmental, but the environmental component is driven by peers and culture, not direct parenting.
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There isn't a direct gene for ADHD or depression, but there is a 'sensitivity gene' that makes individuals more susceptible to stress. According to epigenetics, present and nurturing parenting in the first year of life can effectively neutralize the expression of this gene, preventing future mental illness.
We attribute personal flaws to our upbringing while claiming strengths as self-made. This overlooks that challenging childhoods often forge resilience and ambition alongside negative traits. The wound and the gift often share a root.
Parenting isn't a one-way street. A child's inherent temperament (e.g., ADHD, agreeableness) actively shapes parental reactions. This creates powerful feedback loops where, for instance, a difficult child elicits stricter parenting, which in turn affects development. The outcome is often misattributed solely to the parenting style.
Parents obsess over choices affecting long-term success, but research suggests these have minimal effect on outcomes like personality. Instead, parenting profoundly shapes a child's day-to-day happiness and feelings of security, which are valuable in themselves and should be the primary focus.
Ideologies that rely on a 'blank slate' view of human nature have made a catastrophic error. As genetic technologies become mainstream, the public is forced to confront the tangible reality of genetic predispositions in their own reproductive choices. This will unravel the blank slate worldview, a cornerstone of some progressive thought.
Countering the idea that parenting has little effect on outcomes, a twin study found that the twin receiving slightly more maternal affection between ages 5-10 grew up to be more open, conscientious, and agreeable. This suggests that small, differential parenting choices have measurable long-term consequences for personality.
Attributing traits to either genetics or environment is a false dichotomy. As the genetic disorder PKU shows, outcomes depend on the *interaction* between the two. Believing a trait is purely "in our genes" wrongly dismisses the power of environmental interventions, which can completely alter outcomes.
It's a myth that all cells are a 50/50 blend of parental DNA. Neuroscientist Catherine Dulac's work shows that entire brain areas can be genetically identical to either the mother or the father. This explains why certain behaviors and traits are so strongly inherited from one parent.
Your outcomes are influenced not just by your own DNA but by the genes of those in your social environment, a concept called 'genetic nurture.' A spouse’s genes can affect your likelihood of depression, and a child's genes can evoke specific parenting behaviors, showing that the effect of genes doesn't stop at our own skin.
Trying to determine which traits you inherited from your parents is clouded by the 'noise' of shared environment and complex psychological relationships. For a more accurate assessment, skip a generation and analyze your four grandparents. The generational remove provides a cleaner, less biased signal of your genetic predispositions.