Really great project - would almost have convinced me that computers can actually create art, if I didn't know there were a great coder behind it all :)
One interesting observation - I turned up the output resolution without changing the target fitness and started noticing that the (larger) results didn't look nearly as much like faces to me. At first I thought there must be a technical reason for this, until I realized that it was all psychological - the smaller images hold less information, and therefore my brain has to try harder to fill in the gaps, tricking me into believing that the low-res faces have more detail than they actually do. To prove this to myself, I scaled down the larger images and - sure enough - the (imagined) faces became much more believable.
One interesting observation - I turned up the output resolution without changing the target fitness and started noticing that the (larger) results didn't look nearly as much like faces to me. At first I thought there must be a technical reason for this, until I realized that it was all psychological - the smaller images hold less information, and therefore my brain has to try harder to fill in the gaps, tricking me into believing that the low-res faces have more detail than they actually do. To prove this to myself, I scaled down the larger images and - sure enough - the (imagined) faces became much more believable.