I've long been aware of sameness in people. Back in the day,all mainland Chinese wore Mao jackets, and there were no Yao Mings then. Visiting ballet companies from the Soviet Union didn't present much diversity in size or complexion. Military parades showed soldiers almost uniform in height. We still see some of this when viewing reports from North Korea, although my impression is that there's more diversity at least in dress there.
I've always related this uniformity to cows and hens--visitors to the farm could not see how we could recognize our cows by sight--to them all cows looked the same. We of course knew different, but when it came to our hens they really did all look the same. (Not really--when looking at group of hens I'd recognize differences while I was looking, but it wasn't possible for the differences to make enough of an impression for me to remember individual hens the next day.)
Anyhow, what's interesting to me in this picture is how similar all the Senators, and onlookers, look. They're all dressed the same, and their faces look the same--typical WASP faces. Compare the picture above with this showing the new House members: