studying anthropology is meaningless to future selection, it can only tell you what was selected for in past...it doesn't invalidate anything since evironmental condition (which includes all human activity) can change so can the direction of selection...and 20th century being the most violent/deadliest would suggest it may its becoming more selected for?
I had in mind cultural anthropology more than physical/biological anthropology.
Learn a bit about interactions within and between groups, for example.
according to the idea of commmon decent doesn't "environmental conditions" include all "human activity" in which case culture is collective human activities within groups. and the interaction between "cultures" would also be subject to and be part of "environmental conditions" this would cause interactions to change, or not, become more violent or less, moral or less, depending on selective pressures?