Brighton always has the power to surprise, and should visitors also drop into the local museum’s current exhibition on fetishism, they will come across more of the unexpected and occasionally startling. Assembled partly From its own ethnographic collection, the most important in any British municipal museum, the display falls into three parts.

Pushing through black rubber curtains into dim lighting, visitors first come across a room full of African power objects. The most striking are life-size human and animal figures from Central Africa. Most have had nails and blades hammered into them to prompt their spirits to answer a particular request. Sometimes a piece of cloth, strands of hair or other identifying materials are impaled on these nails to remind the power figures of the individual concerned.

These glowering objects are the idols condemned by European missionaries, but for indigenous populations, they embodied positive forces harnessed to shelter families or communities. They were also used to cure sickness, protect against theft, witness oaths and divine the future.

Different figures lent themselves to curing various human illnesses by virtue of the bundles of mysteries associated with them. Such mysteries could be fragments of paper covered with sentences from the Koran, or simply a rag, stone, clay or any other mundane material once it is invested with the power of the figure itself.

In 1931 French surrealists played their favourite game of upsetting the bourgeoisie by displaying Roman Catholic collecting-boxes and images as “European fetishes” during a colonial exhibition held in Paris. For them, fetishism was a living example of the way any object, however perverse, can become specially valued once it is the particular target of human imagination. These collections included objects from nature, which itself sometimes seemed to possess a lively surrealist imagination.

Such objects appear in the cabinets of curiosities displayed in the second room of the Brighton Museum, including one from the collection of the British surrealist Ronald Penrose. Black-lipped pearl oysters jostle for the space with pig-faced puffer-fish. Other cabinets contain boxes of dolls’ eyes, a 19th-Century hoax mermaid and a Pompeian phallic figure of heroic proportions. There is also the obligatory high-heeled shoe in a display.

The final room exhibits fetishism in contemporary art. This is disappointing: a jumble of displays of human hair, bottled laboratory specimens that also talk aimlessly through mouths projected on to them by a video camera, and a 20-minute film of the artist concerned trying on different shoes, once again often of the high-heeled persuasion.

Compared with the austere dignity of the African power objects, this is tacky stuff. But this section helps trace fetishism’s progress from idolatry through to a branch of aesthetics, taking in on the way the psychology of sexual deviation plus the Marxist concept of commodity fetishism in the over-valuation of certain high-status objects in a capitalist economy.

The museum is laying on a programme of lectures covering these various themes, ranging from the Sexualisation of the Aura of Art to A Look at Fetishism in Post-Modern Culture. Schools have the chance to show older pupils this unfamiliar, occasionally risky but still fascinating by-way of the human imagination.

Castle Museum and Art Gallery, Nottingham, July 22 September 24 The Sainsbury Centre for Visual Arts, University of East Anglia, Norwich. October 9 December 10