The World Beyond Your Head: On Becoming an Individual in an Age of Distraction

by Matthew B. Crawford

In the domain of visual perception, cognitive psychology set out to solve a certain puzzle: an indefinite variety of three-dimensional objects can project identical two-dimensional shapes on the retina of an observer. If static optical information is all that is available to the subject, then because such information underspecifies the shapes of surfaces, it follows that it must be supplemented with something else; something going on inside the head of the subject—namely, assumptions about the structure of the world. This is the motivation for thinking that perception involves an inferential process in the brain. This inference is taken to be computational. That is, “cognition consists in the manipulation of symbols, where these manipulations often involve the application of rules for the purpose of deriving conclusions that go beyond the information [that is presented to the eye],” as Lawrence Shapiro writes in Embodied Cognition, his excellent overview of the embodied cognition literature.