Allan Kaprow - Installation art

"Installation art describes an artistic genre of three-dimensional works that are often site-specific and designed to transform the perception of a space. Generally, the term is applied to interior spaces, whereas exterior interventions are often called Land art; however, the boundaries between these terms overlap."
http://en.wikipedia.org/wiki/Installation_art

Installation art uses existing objects, instead of conventional paint and paper, to create the art. Damien Hirst famously takes once living creatures and sinks them in formaldehyde, places pigs heads with a nest of flies in a sealed plastic/glass box. 
Installation art is used to make the observer think. Its less what something looks like, and more the artists interpretation of the world, themselves, the people around them. It can be anything - one of the first, and most famous examples is Marcel Duchamp's Fountain - a urinal signed R. Mutt 1917. 
"Under the guise of an assumed name Duchamp submitted a male public convenience-type urinal as an entry for a putatively open exhibition in New York in 1917. With this work Duchamp metaphorically urinated on the bourgeois art institution and its adoration of what he referred to disparagingly as ‘retinal art’. Duchamp deliberately picked the most antiaesthetic object he could find in order to attack traditional concepts of beauty. A newspaper article—probably authored, or informed by, Duchamp—argued that Fountain was art because its maker, the fictitious R. Mutt, had declared that it was art. What is remarkable about Fountain is that what appears to have started out as a provocation became transformed into one of the most significant works of art of the twentieth century.
"The reason for this transformation, however, lies less in the intention of the artist than in subsequent interpretation. During the 1960s artists and theorists began to realise that Fountain was something of a founding gesture that pointed to the fact that just about anything could be defined as a work of art so long as it was framed by the institutional apparatus of an art gallery
"During the 1960s and 1970s we find artists attempting to defy the power of the art museum by making art that could function outside its framework. Salient instances include happenings, land art, body art, performance art, mail art and out-of-gallery situational art such as the work of Alan Kaprow, which Claire Bishop points to as one of the precursors of contemporary installation art. The pioneering work of Kaprow, Dan Graham and Hélio Oiticica in the 1960s and 1970s represent installation art before it became congealed into an institutional form. From the 1990s onwards installation art became fine art, ensconced and applauded in an established gallery environment—literally, and willingly, institutionalised." http://artintelligence.net/review/?p=29


Allan Kaprow creates 'unique' events where the viewer is part of the art. He called this art "Happenings", since they were shaped by the audience just as much as by him; they had an 'unfolding narrative' caused by interactions of the people and the objects. One influence for this John Cage, a radical musician during the 1950's, of native American origin; Cage was experimenting with moving towards theatre as an art medium.

His influence changed the perception art; art could be "anything at all, including movement, sound, and even scent"http://www.theartstory.org/artist-kaprow-allan.htm. He believed that the world was more inspiring, more interesting than any and all masterpieces he had seen. This was shown through his unconventional media and art work, for one he created large ice rectangles - and encouraged the public to touch, and smell - generally interact with the ice block.

"The action collages then became bigger, and I introduced flashing lights and thicker hunks of matter. These parts projected further and further from the wall into the room, and included more and more audible elements: sounds of ringing buzzers, bells, toys, etc., until I had accumulated nearly all the sensory elements I was to work with during the following years....I immediately saw that every visitor to the environment was part of it. And so I gave him opportunities like moving something, turning switches on -- just a few things. Increasingly during 1957 and 1958, this suggested a more 'scored' responsibility for the visitor. I offered him more and more to do until there developed the Happening.... The integration of all elements -- environment, constructed sections, time, space, and people -- has been my main technical problem ever since." Allan Kaprow 1965 
http://www.lichtensteinfoundation.org/allankaprow.htm

"Kaprow presents a contradictory portrait; an artist seeking the direct and ephemeral relations between art, the artist, and the audience achieved in the "here and now" of everyday life, and a deep and prolific thinker, teacher and writer who meticulously planned and theorized every instantiation of his work. His lifelong quest to "unart" art practice had a profound and lasting impact on his contemporaries and on artists since, paving the way for Pop art, Conceptual art, Minimalism and new genre public art of subsequent decades. The embodied experience of the environment and the performative and real-time elements of happenings foreshadowed the Installation and Performance art common in contemporary practice, paving the way for artists like Vito Acconci, Suzanne Lacy, and Marina Abramovic."
http://www.theartstory.org/artist-kaprow-allan.htm