@fishywaters
One of the most striking differences to me is between rural and urban families. I grew up in the countryside, and as such know all the rules about how to behave, can identify lots of plants and species that people seem astounded that I know. (MIL seemed to think I was the antichrist for answering a question on The Chase about fungi).
But I also know how to navigate a city, because urban is the default experience and it's represented a lot in film and tv, and I visited towns and cities.
I don't know these things because I'm smart, I know them because I've been exposed to them. I have the cultural capital of two environments, and urbanites tend to have a very sketchy understanding of rural affairs/specific knowledge.
The same can be applied to all modes of culture: TV, music, clothes, sports, art, history, foreign cultures, food.
I visited every country in Europe before the age of ten, but due to parental food issues, barely tried any local food.
I could quote most Monty Python by age ten, watch I, Claudius, read Asterix at the library every Saturday (all interlinked Roman knowledge) - but to this day I've never seen an episode of Eastenders.
People are right to say that cultural capital is a broad range, but wide exposure is really important for brain development, experience and empathy. And as I said upthread, some children even lack the cultural capital on a very simple level of having been to the beach.