The word cognition refers to every kind of mental process that involves knowledge or thinking. Cognitive psychology is the branch of experimental psychology that deals with mental processes, such as perception, language comprehension, or skilled movement. All of these involve internal representation. The phrase "internal representation" includes all our knowledge of the world, including emotional knowledge and social knowledge: knowledge of ourselves, our bodies and minds, and those of other people. Roger Schank, an influential cognitive scientist, said simply, "We have in our minds a model of the world" (Schank, 1983).
We take the world inside us in order to participate in it. Just as the musical person can literally "play" a familiar song within imagination, athletes can imagine complex motor movements, other people can imagine moving around a familiar environment, and about 97% of us can generate pictures or images in our minds. Cognitive psychology makes it clear the human brain is the ultimate synthesizer.
The late 1970s witnessed the emergence of a new discipline called cognitive science, a combination of all the specialties dealing with intelligent information processing, notably including cognitive psychology, artificial intelligence, and linguistics.
Cognitive scientists are interested in both the software (the logic and information processing) and the hardware (brain mechanisms) of human cognition. Cognitive neuroscientists combine investigation of brain processes and cognitive psychology. Brain scanning technologies gave a boost to cognitive neuroscience in the 1990s, and brain scanning seems to be everywhere in the 2000s. Many universities are adding brain scanners (which are typically very expensive) to their laboratory facilities, and hardly a week goes by without a news story about some psychological process (humor, fear, religious feeling) being related to activity in brain areas. Still, we have barely started down the path of understanding cognitive science. Perhaps one day we will look back upon this era as the opening steps of a very long journey toward understanding the workings of the mind.
How this chapter is organized
We start with visual scene analysis, an approach to visual perception pioneered by Artificial Intelligence (AI) researchers at MIT. It establishes a theme that recurs throughout the chapter: that cognitive products are assembled in an atmosphere of constraints in a process resembling problem solving. We also discuss mental imagery in the section on visual perception and review evidence for at least two types of human imagery.
The second section of the chapter discusses language. We review the stages of language development in humans, then we examine the problem of language comprehension, which turns out to bear a fundamental resemblance to the problem of visual scene analysis. Motor activity, the focus of the third section, is not something most people associate with cognition. But it follows the same pattern as other cognitive activities. It is creative, it is based on schemata, it can be conscious or unconscious, it can be represented in imagination.
Finally, in the fourth section, we discuss thinking and problem solving. We review computer simulations of problem solving, from the general problem solver (GPS) to expert systems, to SOAR, a program that attempts to combine the earlier approaches.
Related topics in other chapters
Chapter 1 (Psychology and Science) describes the earliest work on mind and consciousness, as well as the cognitive revolution in the 1970s. Chapter 3 (States of Consciousness) begins with a discussion of conscious and unconscious processing, the concept of attention, and Neisser's proposal for two modes of consciousness. Chapter 4 (Senses and Perception) presents gestalt psychology, size constancy, and depth perception in the visual system. Chapter 6 (Memory) is entirely devoted to a subdivision of cognitive psychology. Chapter 8 (Animal Behavior and Cognition) includes research on cognitive processes of animals. Chapter 9 (Motivation and Emotion) includes a section on cognitive motives, Chapter 10 (Development) contains a section on cognitive development in children, and Chapter 15 (Social Psychology) features a section on Social Cognition.