The peacock's tail gave Darwin considerable grief. A single feather made him feel "sick". The bird's cumbersome display seemed to confound the guiding principle of natural selection: that any evolved form should answer fittedness to environment. Not until his last book, The Descent of Man, did he come up with a satisfactory answer based on "natural selection in relation to sex". Even in his final years, Darwin had little to say about aesthetics but his theory of evolution does prepare the way for a comprehensive understanding of what art is and why we make it.

Denis Dutton's title is also his conclusion. In 250 elegant pages, he demonstrates that aesthetics are linked at the profoundest level to our biological and cognitive prehistory, and that our "tastes" - those famously wavering and manipulable urges - emerged in the Pleistocene, and haven't changed in essentials since then. For Dutton, cultural relativism is an academic parlour game. Human arts speak to a universal human nature different only in plumage.

This is an interpretation that runs counter to the view - held by Stephen Jay Gould among others - that art is merely the by-product of an over-sized brain and should be excluded from the natural selection rulebook. Evolutionary biologists have argued that human emotions emerged as a mechanism for orchestrating specific biological needs, harmonising potential actions in a useful way. Fear is a way of getting the body prepared for potential dangers. When risk and therefore fear are no longer aspects of day-to-day survival - no sabre-tooths on Hampstead Heath! - fear remains with us as an objectless emotion, and evolution leads smoothly on to Hammer House of Horror.

Dutton wisely recognises this just doesn't work, and not only because risk obstinately fails to disappear. What troubles him is the separation of emotion, and thus art, from its causes, which remain ever with us. In the same way, he attacks the relativism (and shaky methodology) of anthropologists who confidently, and self-protectively, announce that a given culture's "concept" of art is "different" to ours. Nonsense, says Dutton. They either have a concept of beauty, or they don't.

Like our remotest ancestors, we take delight in virtuosity, we admire personal expression and novelty, we enjoy intellectual challenges that give pleasure in being mastered, and we benefit immeasurably from the sense of communion and intimacy these experiences bring us. This is art: then, now and always.

Is there a connection with the peacock's tail? In The Descent of Man Darwin draws a line backwards from the present-day "orator, bard or musician" who "little suspects that he uses the same means by which his half-human ancestors aroused each other's ardent passions". In his final cadences, Dutton manages to reference The Last Supper, the "Pastoral Symphony", Fantasia, Duchamp, John Cage and Tracey Emin, and then scrolls back to the first daubs of red ochre on a human face. How far apart? How close? "Preoccupied as we are with the flashy media and buzzing gizmos of daily experience, we forget how close we remain to the prehistoric men and women who first found beauty in the world. Their blood runs in our veins. Our art instinct is theirs."