Head sizes - getting bigger?

Factual Questions
1

Twice this week I have heard that British people’s heads have got bigger since the 19th century. Both times were in the context of buying vintage top hats - people want them to wear at the Ascot races or the opera etc. It was said that it is pretty easy to pick up an old top hat but it is very unusual to find one that will actually fit a modern head. Even the top hat manufacturers themselves have large stocks of the smaller sizes which they cannot shift.

I understand that the lower jaw is getting smaller because we do not do as much chewing as our grandparents did. But why is the top of the head getting bigger? (Surely it cannot be to accommodate larger brains?) Or is it simply because our bodies are bigger in general and so proportionally are our heads?

2

Yup.

3

I saw a show on the History channel that mentioned a similar effect for historical artifacts that were some sort of apparel - things that were abnormally small, (or less often, abnormally large) were most of what was left. This was leading people to think that people in the past were much, much smaller. In fact the artifacts, at least in some cases, were showing a survivorship bias; those items that were in common sizes has been used, reused, and eventually throw out when completely worn, versus those that were oddly size being found because they had seen less use.