Steven Pinker -- How the Mind Works - Hampshire High Italian ...

The Mind's Eye 255image, and it just paints it in. The program thinks it is looking at a painting.Once the program has a chance to adjust its guesses, it settles intothe interpretation shown in the middle row. The shape specialistfinds the most regular 3-D shape (shown in side view in the left column):square panels joined at right angles. The lighting specialistfinds that by shining the light from above, it can make the play ofshadows look something like the image. Finally the reflectance specialisttouches up the model with paint. The four columns—zigzag 3-D shape, lighting from above, shadow in the middle, light stripe nextto a darker one—correspond to how people interpret the originalimage.Does the program do anything else reminiscent of humans? Rememberhow the fanfold flips in depth like a Necker cube. The outer foldbecomes an inner one, and vice versa. The program, in a way, can see theflip, too; the flipped interpretation is shown in the bottom row. The programassigned the same costs to the two interpretations and arrived atone or the other randomly. When people see a 3-D shape flip, they usuallysee the direction of the light source flip, too: top fold out, light fromabove; bottom fold out, light from below. The program does the same.Unlike a person, the program does not actually flip between the twointerpretations, but if Adelson and Pentland had had the specialists passaround their guesses in a constraint network (like the Necker cube networkon p. 107 or the stereo vision model), rather than in an assemblyline, it might have done so.The workshop parable clarifies the idea that the mind is a collectionof modules, a system of organs, or a society of experts. Experts areneeded because expertise is needed: the mind's problems are too technicaland specialized to be solved by a jack-of-all-trades. And most ofthe information needed by one expert is irrelevant to another and wouldonly interfere with its job. But working in isolation, an expert can considertoo many solutions or doggedly pursue an unlikely one; at somepoint the experts must confer. The many experts are trying to makesense of a single world, and that world is indifferent to their travails,neither offering easy solutions nor going out of its way to befuddle. So asupervisory scheme should aim to keep the experts within a budget inwhich improbable guesses are more expensive. That forces them tocooperate in assembling the most likely overall guess about the state ofthe world.