A nonviolent childhood is the very foundation of a peaceful society.
If you take a look at the worldwide legal situation: https://en.wikipedia.org/wiki/Child_corporal_punishment_laws ,and try to find the missing countries on the Global Peace Index you will find most of them on the lower ranks, whereas countries with a long-lasting legal ban on child corporal punishment are the most peaceful ones.
You can still find detailed data on: www.endcorporalpunishment.org , which has been merged with www.end-violence.org in 2020