Horn spent most of her late childhood in boarding schools and at nineteen rebelled against her parents plan of studying economics and decided to instead attend Hamburg Academy of Fine Arts. A year later she had to pull out of art school because she had contracted severe lung poisoning. 'In 1964 I was 20 years old and living in Barcelona, in one of those hotels where you rent rooms by the hour. I was working with glass fibre, without a mask, because nobody said it was dangerous, and I got very sick. For a year I was in a sanatorium. My parents died. I was totally isolated.” After experiencing this “total isolation” until she felt that her life was over before it had begun, she walked out of the hospital. She was still too ill, however, to resume life as a student or work with fiberglass and polyester. She had to take masses of antibiotics and sleep long hours to have enough energy to operate normally. She could, however, work with softer materials, and when in bed she drew with colored pencils (which are still her favorite drawing tools). She also began to slowly break out of her self-imposed isolation and began to create sculpture and strange extensions with balsa wood and cloth. “I began to produce my first body-sculptures. I could sew lying in bed." Her goal then was to quash her “loneliness by communicating through bodily forms.”
When Horn returned to the Hamburg academy she continued to make cocoon-like things. She worked with padded body extensions and prosthetic bandages. In the late sixties she began creating performance art and continued to use bodily extensions.
'Unicorn' is one of Horn’s best known performance pieces. Its subject is a woman who is described by Horn as “very bourgeois” is “21 years-old and ready to marry. She is spending her money on new bedroom furniture,” walks through a field and forest on a summer morning wearing only a white horn protruding directly from the front of the top of her head and the straps holding it there. Tese straps are almost identical to the ones worn in Frida Kahlo’s painting Broken Column. The image, with wheat floating around the woman’s hips, is simultaneously mythic and modern.
'Pencil Mask' is another body extension piece, made up of six straps running horizontally and three straps running vertically. Where the straps intersect a pencil has been attached. When moving her face back and forth on a near a wall the pencil marks that are made correspond directly with her movements.
'Finger Gloves' is a performance piece and the main prop of that performance piece and was done in 1972. They are worn like gloves, but the finger form extends with balsa wood and cloth. By being able to see what she was touching and the way in which she was touching it, it felt as if her fingers were extended and in her mind the illusion was created that she was actually touching what the extensions were touching. There is another piece that she did that is very similar to this one. It is part of her Berlin Exercises series done in 1974 called “touching the walls with both hands simultaneously”. In this piece she made more finger extension gloves, but this time measured it so that they specifically fit the selected space. If the chosen participant stood in the middle of the room, they could exactly touch opposing walls simultaneously.
Another piece that involves the illusion of feeling and one’s hand is 'Feather Fingers.' (1972). A feather is attached to each finger with a metal ring. The hand becomes “as symmetrical (and as sensitive) as a bird’s wing”. When touching the opposite arm with these feather fingers one can feel the touch on the left arm and of the fingers on the right hand moving as if to touch the left arm but it is instead the feathers which make contact. Rebecca Horn describes the effect: “it is as if one hand had suddenly become disconnected from the other like two utterly unrelated beings. My sense of touch becomes so disrupted that the different behavior of each hand triggers contradictory sensations.” This piece focuses greatly on sensitivity.
Rebecca Horn continued to explore the image of feathers in her works of the 1970s and 1980s. Many of her feathered pieces wrap a figure in the manner of a cocoon or function as masks or fans to cover or imprison the body. Some of these pieces are 'Cockfeather' (1971), 'Cockfeather Mask' (1973), 'Cockatoo Mask' (1973), 'Paradise Widow' (1975), and 'The Feathered Prison Fan' (1978) made for her film Die Eintänzer.
Many Horn works also explore ambiguities in the idea of lenses. One would think that a large tinted lens exists for protection and cover, but it also has the effect of drawing attention to the person or figure behind it. The paradox of looking out and looking back is explored in her installation piece for Taipei 101, Dialogue between Yin and Yang (2002). The work sets up interactions between viewers, environment and sculpture as it uses binoculars and mirrors to suggest the passive and active energies.
Rebecca Horn's films, in addition to Die Eintänzer (1978), are La Ferdinanda: Sonata for a Medici Villa, and Buster's Bedroom. La Ferdinanda is in German; the other films are in English. In all of these films though, Rebecca Horn’s obsession with the imperfect body and the balance between figure and objects is apparent. She has also collaborated with Jannis Kounellis and produced some films, including the film Buster's Bedroom (1990) with Donald Sutherland.
Rebecca Horn is the subject of a book entitled 'The Glance of Infinity'.