In the 40's you had two choices, option one, suck your thumb, or option two, go without. My brother had a small piece of ribbon which he rubbed together between finger and thumb when he went to bed. It was not the done thing for kids to suck their thumb at school, as it was deemed babyish if you were a male child anyway, girls had a different set of values which guys never understood. Sooooooooo, no change there then.