From hand-held DVD players to hundred-inch plasma screens, much of today's technology is driven by the human appetite for pleasure through visual and auditory stimulation. What creates this appetite? Neuropsychologists have found that visual input activates receptors in the parts of the brain associated with pleasure and reward, and that the brain associates new images with old while also responding strongly to new ones. Using functional MRI imaging and other findings, they are exploring how human beings are "infovores" whose brains love to learn. Children may enjoy Sesame Street's fast pace because they get a "click of comprehension" from each brief scene.