The spotlight of attention is more like a strobe light -- ScienceDaily"Our subjective experience of the visual world is an illusion," said Sabine Kastner, a professor of psychology and the Princeton Neuroscience Institute (PNI). "Perception is discontinuous, going rhythmically through short time windows when we can perceive more or less." The researchers use different metaphors to describe this throb of attention, including a spotlight that waxes and wanes in its intensity. Four times per second -- once every 250 milliseconds -- the spotlight dims and the house lights come up. Instead of focusing on the action "onstage," your brain takes in everything else around you, say the scientists. Their work appears as a set of back-to-back papers in in the Aug. 22 issue of Neuron; one paper focuses on human research subjects, the other on macaque monkeys. "The question is: How can something that varies in time support our seemingly continuous perception of the world?" said Berkeley's Randolph Helfrich, first author on the human-focused paper. "There are only two options: Is the data wrong, or is our understanding of our perception biased? Our research shows that it's the latter. Our brains fuse our perceptions into a coherent movie -- we don't experience the gaps."