I was in the local library this afternoon and browsing through the science section. There were quite a number of popular books on neuroscience published across the last fifteen years or so. These were all nice glossy books in their time, with reviews in the science monthlies. Many of them promised on the jacket to reveal how evolution had left our human brains with their curious features, or to otherwise illuminate a new understanding of how our brains evolved.
I took this occasion to ponder just how little about human brain evolution we have learned in the last fifteen years -- older books and more recent ones being superficial in almost equal measure.
Neuroscience has made some very interesting progress in that time, but much of that progress has happened at levels of brain organization and neural function that are irrelevant to human evolution (i.e., shared across mammals). There has been some interesting work on how human brain anatomy compares to other primates, but in these cases we don't yet understand how the differences cause the human anatomy to function differently from those primates. We don't even know the functional significance of most variations within humans. Most remarkable to me is just how little genetics has impacted our understanding of human brain evolution.
I think it would be more productive to compile the big questions we don't know about human brain evolution, with reasons why we don't know them.