We had first grade reader books that used the characters "Tom", "Dick" and "Jane" that described their family adventures. These were not uncommon names in the 50s, and I actually had brothers named Tom and Dick. For a while I believed that all families must have someone named Tom and Dick if they had boys, since those were the names in the reader book.
A childhood belief about names

others believed things like this
- I thought Kaa's name from The Jungle Book was spelled "Car" and that he had a brother named Truck.Anon
- when i was growing up i had two imaginary friends. One was named Jennifer, the other was named Onion.— Tessica
- I used to believe there was a Russian Leader named Garbage Trough and an Arabian named Are A FatAnon
- When I was very young, I believed that my parents actual names were "mum" and "dad". — Margo
- The boy in my class named "Sahand" must have a sister named "Safoot".Anon
- At the age of around five, I realized that my mum's and dad's names were not mum and dad!— yelloworpurple