1. You are assuming brain health means learning. 2. You are assuming fights exert the same effect as exercise. 3. You are assuming the selection pressure is g

1. You are assuming brain health means learning. 2. You are assuming fights exert the same effect as exercise. 3. You are assuming the selection pressure is great enough to effect allele frequency. 4. You are assuming humans fight alone. 5. You are assuming humans have extra knowledge to be gained in a split second of a fight. 6. You are assuming said extra knowledge would be overwhelmingly adaptive in a physical fight. Breaking down adaptation is all about understanding your assumptions. It is easy to speculate, but it is hard measure evolution. However, given rigorous study we can measure adaptation mathematically and quantify it's impacts.