Alternative hypothesis 2

(At this point I should point out that I like your hypothesis, I just think it is not necessarily single-cause)

Satoshi Kanazawa's charmingly simple theory that general intelligence tends to suppress and displace most of your instincts. This means being smart pretty much automatically means being bad at a lot of things. The way I interpret it is that attention is a finite resource and you either pay attention to your analytical engine or your instincts or share it, but you cannot give full 100% attention to both. So if the analytical engine demands your attention the insticts shut up/down.

I have observed intelligent people being bad at the following instinctive things (not all of them, not in all of these):

• social skills
• motoric skills, hand-eye coordination like basketball
• 3D geometry i.e. toolmanship, fixing the plumbing or the lawn mower at home, being a handyman
• drawing
• music, singing
• balance
• rythm, dancing