The Artistic Impulse
Evolutionary psychology faces a fundamental challenge if it is to explain a few peculiarly human activities, such as music, mathematics, and art. How could these abstract activities have had a survival value in their origins? To try to make the point more acute, how could the guy sitting by his campfire decorating his spear have gotten a competive advantage over his counterpart investing the same time and effort into doing him in?
It seems very plausible to me that the artistic impulse had its origins in ordinary pride in workmanship. Fashioning a really effective stone arrowhead is far from being a trivial task. I have noted previously on this blog that the human hand is equipped with muscles and control that our fellow great apes lack, and that these muscles give us a precison of control that they lack - chimps, at least, seem to be able to grasp the notion of making a projectile point but lack the fine motor control to be good at it.
Just as the muscles and wings necessary for flight would be useless without the instinctive impulse to launch oneself into air, the muscles and precision control necessary to make good stone tools are incomplete without a corresponding instinct to shape materials with it. Once acquired, the combination acquires a generalized utility far beyond the original functionality.
Consequently, I say, Michaelangelo's David is only a relatively small step beyond a finely wrought mesolithic projectile point.