https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5068715/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5068715/ https://en.wikipedia.org/wiki/Heritability_of_IQ#:~

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5068715/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5068715/ https://en.wikipedia.org/wiki/Heritability_of_IQ#:~:text=Early%20twin%20studies%20of%20adult,for%20late%20teens%20and%20adults https://en.wikipedia.org/wiki/Heritability_of_IQ#:~:text=Ear.... https://scholar.google.com/scholar_url?url=https://www.gwern.net/docs/iq/2002-firkowska-mankiewicz.pdf&hl=en&sa=X&ei=Kl5bYdDdF5LSyQT4lJigBw&scisig=AAGBfm2z77Un2pIk_4tTkGvYQdDwn-lRYQ&oi=scholar https://scholar.google.com/scholar_url?url=https://www.gwern... So genetics plays a significant part in personality traits and iq. Having high conscientiousness is the trait that correlates with work ethic and drive. It's definitely not 100% but genes play a big part. Twin studies are cool - even though there's usually something tragic involved with twins separated at birth, it gives you an excellent way of assessing genetic influences on a huge array of factors.