When our ancestors discovered the trick of consistently producing sharp stone flakes, it constituted a major breakthrough in human prehistory. ...The… - Richard Leakey

It appears that the evolutionary process promotes its own progress: learning about the environment (which demands a certain intelligence) means living in a stable social mileau (which demands at least an equal and possibly a greater intelligence); as social intelligence increases, so too will the ability to learn; this in turn encourages an even longer social apprenticeship; and longer group living leads to more social intelligence.

The French archeologists Iégor Reznikoff and Michael Dauvois conducted detailed surveys of three decorated caves in the Ariège region of southwest France. ...they moved slowly through the caves, stopping repeatedly to test the resonance of each section... spanning three octaves... those areas with highest resonance were also those most likely to harbor a painting or engraving. ...a fascinating discovery that... Chris Scarre commented at the time, draws "new attention to the likely importance of music and singing in the rituals of our early ancestors."

The quality that accompanies the emergence of learning in the evolution of higher animals, namely intelligence, is surprisingly difficult to define.