What was alluded to but not explicitly discussed in depths is 1) epigenetics (in utero nutrition for example, signals to the fetus what type of world they'll be born into and thus how much protein resource to allocate to the brain)<br>and 2) sexual selection which <i>is</i> an evolutionary explanation to the Flynn Effect and why different populations have different average IQs.<br>If intelligence is highly valued in a society (like Singapore, South Korea, China), group IQs will be higher than one where physical prowess is highly valued.<br>Given our bodies have trade-offs to make, physical prowess and mental prowess could easily be genetically and epigenetically inversely related.