what is the effect of slavery times before the book was set

If I understand your question correctly, you are referring to the affect slavery had on the characters of the book? We can see the effect of slavery all through this book even though blacks had been technically emancipated. Virtually every part of life for black people was segregated from whites. Although slavery was outlawed, most black farmers lived in bondage as sharecroppers to white land owners. Blacks still lived in fear of the KKK or "night men" who ran the countryside looking to lynch. So, although the laws governing slavery had changed, the mindset of most of the whites had not.