HI. I am not working on EEG. I am in communication engineering. I think you find the correlation between two chromosomes using standard correlation function. Then according to your problem you decide either to maximize or minimize the correlation.

thanks Prasanta

good luck

Choose maximize correlation as your fitness function or minimize your error of the correlation function

thanks Ramesh , but  the max correlation is my optimum result and I want to reach after running GA, I mean these 2 functions which you suggested, are Indeed the solution of the problem, so how can I compare any chromosome in each generation with these two functions?  

Ramesh, we don't know the values of correlation at all, and at end want to find pairwise correlation between signals, less or more, no matter maximum or not just to find the normalized value of correlation for pairwise time series

thanks dear mahboobeh