You do not have to be an anthropologist to invest in tribal art. Being a Western aesthete will do. Until recently, only carved wooden sculpture - face masks and figures of people and animals - fetched fine art prices in the salerooms. The rest - weapons, domestic utensils, textiles, bead jewellery - were rated not as art but as anthropological specimens.
Now, home makers and interior decorators seeking simple, sensational objects to display in sparsely furnished loft spaces have broadened the market. Install a plinth, apply a spotlight, and a decorated tribal shield becomes art.
Buyers at next month's tribal art auctions and Tribal Art Fair in London would do well to study prices realised at the most recent auctions for examples of the rising value of anthropology. At Bonhams in December, an Australian Aboriginal stone tchuringa a little over 7ins high - a ritual object traditionally hidden out of sight of women - fetched a whopping pounds 2,990, nearly four times its pre-sale estimate. Five years previously it had fetched a mere pounds 150 at a Phillips auction.
The reason for the price jump? It was incised on both sides with a network of parallel lines linked with concentric circular medallions. To an Aborigine, it tells of the mythic "dream time". In Western eyes, that's art. The prices of Aboriginal bark paintings bearing comparable designs are going through the roof at Sotheby's annual June sales of Aboriginal art in Melbourne.
The powerful but seemingly paradoxical allure that tribal art (still sometimes described as "primitive" art) exerts in our advanced post-Renaissance culture is explained by two examples from art history, one recent, the other occurring in 1907.
In that year, Picasso first clapped eyes on African carvings in the Palais du Trocadero's ethnographic museum. He was transfixed, and his art transformed. The immediate result was that his five nude female figures, Les Demoiselles d'Avignon, then in progress, convulsed into hard-angled shapes with heads like African masks.
For 30 years, the canny Picasso refused to acknowledge his artistic debt. "African art? Never heard of it!" he would say. But when the secret came out, prices of tribal masks and figures began to rise.
Anthropological specimens in general did not truly enter the Western art market until the Royal Academy's blockbuster exhibition Africa: The Art of a Continent in 1995-96 - curated by an artist, Tom Phillips. The exhibition outraged anthropologists. Here were tribal artefacts from Western private collections that had been torn from their archaeological context and were now being hailed as art by Western aesthetes. Phillips retorted impishly that the Venus de Milo had been torn from context, too. "The test of art," he said, "is whether it can survive independently of context."
The biggest controversy centred on the exhibition's carved five-seated stool from the Ngombe area of Zaire, which was pegged into its stand vertically, instead of horizontally, as if it was an abstract sculpture. One scholar fumed: "Duchamp has gone to Africa." But the die was cast. The exhibition stitched art irrevocably into "tribal art".
That five-seater still stands provocatively upright in the home of its owner, the London tribal art dealer Peter Adler, son of the harmonica player. Customers buy his earth-coloured geometrically patterned Shoowa rafia cloths from Zaire (pounds 250-pounds 600) and big Fante flags from Ghana (pounds 400- pounds 2,200) in order to frame and hang in sitting rooms in Islington and loft spaces in Farringdon. Senufou beds from Upper Volta, long planks of wood with headboards (pounds 1,000-pounds 3,000), serve as coffee tables.
All of Adler's stock is old, that is, pre-1950. It has come from reputable Western collections. He never buys from Africa. Authenticity is all-important in this market, which, with the advent of tourism, is bedevilled by contemporary batch-produced "airport art".
Objects that have actually been used in tribal rituals, such as fertility rites, carry an added cachet. Perhaps Picasso was right when he said that his experience in the Trocadero had taught him that art is "a form of magic".
An unwanted Western look makes Makonde masks from Tanzania and Mozambique hard to sell. They have an eerie realism. Some are of the Virgin Mary - evidence of Catholic Portuguese colonial influence. Fiona McKinnon, tribal art dealer and organiser of the Tribal Art Fair, finds it easier to sell fierce-looking Marka masks from Mali. This one, covered in hammered brass strips, is pounds 1,400. The Makonde Virgin is pounds 700.
Australian aboriginal art is rising fastest in price - estimates for two carved shields, pounds 800-pounds 1,000 each in Bonhams' forthcoming sale, are modest - they are likely to be fought over. South African (notably Zulu) and native American prices are being pushed up by guilt-ridden native whites. Polynesian prices are as strong as ever.
The Eurostar rail link is bringing more Belgian and French day-trip bidders in search of former colonial tribal artefacts - Congolese, for example. Look for bargains among neck rests, stools, shields and weapons with finely carved, unusual designs and a patina from handling. Use your Western eyes. They're the only ones you've got.
Bonhams Tribal and Pre-Columbian Art sale: 3 June, 2pm (inquiries: 0171-393 3900).
Phillips Tribal Art and Antiquities: 25 June, 11am (inquiries: 0171-629 6602).
Tribal Art Fair: Elms Lesters Painting Rooms, Flitcroft Street, Soho, London WC2H 8DH, 7 and 8 June, 11am-6pm (inquiries: 0171-836 6747).
Peter Adler: 0171-262 1775