As a small child I was absolutely convinced that people in the olden days lived their day to day lives in black and white, and that they walked slightly faster than we did today (assuming a frame rate thing?).
I'm gonna put this one down to my understanding of how TV worked as a ten year old. Everything before colour TV was black and white... therefore everything was black and white. Makes perfect sense.
What about you?
I didn't believe in dinosaurs. I thought evolution meant "things got bigger," so the idea of these roaming giants was completely unbelievable.