This reading suggests that video art has been around for nearly four decades. Video art/installations have become a dominant avant-garde art form in the United States. Video art never looses strangeness nor challenge. It is thought to pose difficulties for viewers. Video installations often require the viewer to occupy real time in order to experience and get the most out of the medium. The minutes usually pass by slowly in a video installation. The average gallery or museum visitor spends only a few seconds before each painting or sculpture whereas video art takes more time to comprehend and analyze. Video art requires you to stand among others and wonder what to do with yourself, your material self, as you spend anywhere from two minutes to an ten or twenty watching a stream of images on a monitor or a projection onto a wall. Video installations can often make you visible to yourself. Its almost like you become a social presence confronting yourself and others, and can become part of the art work itself. This type of art has a tendency to allow the viewer to wind into another state of mind, often forgetting about reality or escaping for a duration. The time-based nature of video relates to its difficulty to engage and comprehend. "Video artists like Bill Viola are very good at using this medium to anatomize human perception, dissecting its mechanics and ideologies." Much of Bill Viola's work since the mid-1970s, reflects on video as a medium and engages in a search for its metaphorical capabilities. If Viola's work is occasionally "difficult" it is because of the ideas he wishes his viewer will consider as they experience his installations. Video installations can often provide an emotional rush and fascination. Installations incorporate effects like sound, motion, text, stills, etc. Most of Viola's videos and installations are about the relationship between the artistic act and the viewer standing in or before the work. Engaging himself as well as engaging the viewer is what concerns Viola as an artist.