I have read that when bosons interfere they do so by adding the probability amplitudes, then I read that when fermions interfere they do so by subtracting the probability amplitudes.
The usual double slit interference pattern has a bright fringe in the middle and weaker fringes around it. If electrons (with same spin) are used and they interfere by subtracting the amplitudes, then we would get an inverteda negative interference pattern with a dark fringe in the middle and two fringes of equal strength around it don't we?