Neuroscientist Lisa Feldman Barrett: The structure of the brain is such that there are many more intrinsic connections between neurons than there are connections that bring sensory information from the world. From that incomplete picture, she says, the brain is “filling in the details, making sense out of ambiguous sensory input.” The brain, she says, is an “inference generating organ.” She describes an increasingly well-supported working hypothesis called predictive coding, according to which perceptions are driven by your own brain and corrected by input from the world. There would otherwise simple be too much sensory input to take in.