There is no scientific proof that coat color effects temperment- but there is indisputable evidence that certain coat colors produce certain characteristics, and drives.
Go to a psa field, mondioring trial, look at true working gsds, civil k9s from any breed. You will notice certain colors produce harder dogs. Can't be denied, like I said b4 I can care less about color but I don't see a lot of civil aggresive white gsds, I don't see a lot of game blue apbt, in the last 7 years I have only seen a hand full of black filas with correct temp. Does this mean I would not and don't have filas with black dogs in the pedigree, of course not but knowing there was a serious possibility these dogs would have weaker temp I researched and went out and saw as many of the dogs in first 4 generations as I could because when you want to preserve certain characteristics in any breed you have to take into consideration EVERY factor, scientific are not you consider and strategize by looking at all variables and factors. its a fact that in any breed color seems to play a factor in temp. A small factor but still a factor, look at the temp of black boerboels, evaluate the majorty of blue c.c..