Perception as Unconscious Inference

Consider for a moment the spatial and chromatic dimensions of your visual experience. Suppose that as you gaze about the room you see a table, some books, and papers. Ignore for now the fact that you immediately recognize these objects to be a table with books and papers on it. Concentrate on how the table looks to you: its top spreads out in front of you, stopping at edges beyond which lies unfilled space, leading to more or less distant chairs, shelves, or expanses of floor. The books and paper on the table top create shaped visual boundaries between areas of different color, within which there may be further variation of color or visual texture. Propelled by a slight breeze, a sheet of paper slides across the table, and you experience its smooth motion before it floats out of sight. The aspects of visual perception to which I’ve drawn your attention are objects of study in contemporary perceptual psychology, which considers the perception of size, shape, distance, motion, and color. These phenomenal aspects of vision are sometimes contrasted with other, more typically cognitive aspects of perception, including our recognition that the objects in front of us include the table, books, and paper, our seeing that the table is old and well crafted, and our identifying the sheets of paper as the draft of an article in progress. All of these elements of our visual experience, whether characterized here as phenomenal or cognitive,1 seem to arise effortlessly as we direct our gaze here and there. Yet we know that the cognitive aspects must depend on previously attained knowledge. We are not born recognizing books and tables, but we learn to categorize these artifacts and to determine at a glance that a table is an old one of good quality. What about the phenomenal aspects? A persistent theme in the history of visual theory has been that the phenomenal aspects of visual perception are produced by inferences or judgments, which are