I saw that photo in color and missed it by +2 years. In color, at least, it's very obviously 'retro' and the phrase on the sign is not particularly 60's. I got

I saw that photo in color and missed it by +2 years. In color, at least, it's very obviously 'retro' and the phrase on the sign is not particularly 60's. I got two others within a year or two, but it was because I recognized the events. One I really flubbed was the two little boys on the junk pile (mine was color), which I guessed was related to the Fall of the Berlin Wall. Since the color average was '87 and the black-and-white '85, I'm guessing that's what most people thought regardless of color. The most difficult one for me was the 'street parade', which could have been many, many moments. In all cases, regardless of color or black-and-white I wasn't using whether the photo was color or black-and-white to determine the date. I was first trying to guess the possible events, and then trying to rule them out based on clothing, style of cars, architecture, etc. etc. I think a bigger problem is where to initially put the selection knob. The knob on the picture of the two 'hippy' women was placed around '64 (if I remember correctly), confirming the bias in my brain "60s == hippy". I suspect most people link the selection knob mentally as a sort of 'caption' of the photo, even though they know consciously it's the selection tool.People are also probably slightly less likely to move a slider further than closer.