The most widespread misconception about evolution/selection is that it is a purely genetic process whose outputs are then further affected by ancillary processes like epigenetics, socialization, culture, ideology, etc
In truth, the entire human enterprise is an evolved process. Genes are just one physical manner by which traits can be passed from generation to generation in biological organisms and are subject to their own limitations. The evolutionary process is much more resourceful and clever than that. Consider, for example, the unusually long period of dependence humans exhibit after birth. They require between 10 and 20 years of supervision before they are sufficiently prepared for independent survival, and even then don't fully finish brain development until the age of 25. Why is this?
The widely accepted explanation involves (at least in part; evolution is somewhat omnicausal and can't be neatly parsed) skull size. Informational storage capacity and computational power are both processes that require actual physical matter to occur. More matter (or to be more precise, more possible physical configurations of the matter) increases the upper potential bound of both. As our ancestors' environmental pressures selected for greater and greater intelligence, the size and/or density of our brains increased to provide it. The theory states that at some point, our heads began to approach a size that would require such a wide birth canal in females that it would hinder their mobility. This put a limit on skull size, but there were still pressures for increased intelligence. Evolution, ingeniously and through trial and error, essentially extended our incubation period to beyond the womb, developing the brain in utero until it was the largest it could be (no wonder birth is painful), then pushing it out into the world where it continues to grow. 1/2
