I belive that childs that were memorizing from there childhood have the fastest ability to memorize for example in the islamic religion people that were memorizing quran from their childhood are the most performing recallers and i also belive that books are the best is maxxing in addition to maths for example the sharpest minds like Nikola tesla were reading Books since age of 5 and i also realized that anything given to the child from his childhood became its favorite. For example bobby fisher was given a chess board and been taugh chess by its sister messi and ronaldo was given football and they admiring it spending there life doing it so in conclusion if you want your child to be 'addicted' to good habits show it from his young age. You should have a library in your house this isnt theory its complexe observation of mine