Perhaps an 'across the pond issue?

Let me start off saying this is not a complaint, just curiosity.

I really enjoy QUEEN'S GAMBIT by Maeryn! However there is one area that tweaks my sensibility. It is VERY minor but I thought to question it and in no way means an insult or complaint. I simply want to know if this is an "across the pond" difference.

Namely using head movement to denote YES or NO.

In my American experience, I learned that to shake one's head means moving it side to side to denote NO. To denote YES, one nods their head.

As I said, a minor issue but when I see a story where the character shakes their head to denote YES causes a slight dissonance of the flow.

If I'm being silly, tell me. Thanks