I think the point was just that your personality is in large part a biological construct influenced by the soup of factors that is your physical body. If we cou

I think the point was just that your personality is in large part a biological construct influenced by the soup of factors that is your physical body. If we could somehow transfer your "soul" (if there is such a thing) in someone else's body, your personality would likely change. How much? We don't know, but it would be non-zero. It's not just your brain, or your hormones, but also stuff like your guts biome. Even if some of these are temporary and fluctuate, they'll still be part of "who you are". But our general's health, socioeconomic context, influence of discrimination (or privilege), peer and society's pressures, etc, also impact our personalities in big ways, so it's pretty tough to separate one from the other. Heck, even what you eat can change it. If you google around, you'll find how people who eat a lot of trans fat were found to be generally more aggressive.