I wonder about a lot of irrelevant things when I should be doing something useful. One thing that I've been wondering about recently is the motorcycle helmet. I know next to nothing about motorcycles. But I have noticed that, over most of my life, a motorcycle helmet has been a thick, bulky, visored contraption that protected, and concealed, everything above the neck. Some time in the last year or two, motorcycle helmets suddenly turned into small black soup bowls that cover only the top of the head. If the trends continues, in a few more years we will be looking at the motorcycle yarmulke.
Was the shift in styles strictly a matter of fashion? Or was it discovered that the old helmets didn't offer any significant advantage in skull protection? I suppose that I could find out by using the all-knowing, all-seeing Internet, but I don't really care all that much.