You don't work full 12 hour continuously. You'll take numbers of breaks in between, for example lunch, snacks, napping, coffee, stroll around, exercise, gym, meditation, games, etc.
> The 7-8 hour person will create better products with fewer bugs
the 12 hour person with sufficient breaks can't do that ? whats the reasoning ?
Maybe I'll put my bed in the office, that way I can "work" the full 8 hours ;).