Cognitive Psychology.

Cognitive Psychology. I INTRODUCTION Cognitive Psychology, the scientific study of cognition. Cognition refers to the process of knowing, and cognitive psychology is the study of all mental activities related to acquiring, storing, and using knowledge. The domain of cognitive psychology spans the entire spectrum of conscious and unconscious mental activities: sensation and perception, learning and memory, thinking and reasoning, attention and consciousness, imagining and dreaming, decision making, and problem solving. Other topics that fascinate cognitive psychologists include creativity, intelligence, and how people learn, understand, and use language. Over the years, cognitive psychologists have discovered that mental activities that seem simple and natural are, in fact, extraordinarily complex. For example, most children have no trouble learning language from their parents. But how do young children decode the meanings of sounds and grasp the basic rules of grammar? Why do children learn language more easily and rapidly than adults? Explaining these puzzles has proven very difficult, and attempts to duplicate true language ability in machines have failed. Even the most advanced computers have trouble understanding the meaning of a simple story or conversation. Cognitive psychologists have found similar complexity in other mental processes. Cognitive psychology is one field within cognitive science, an interdisciplinary approach to the study of the human mind. Other fields in cognitive science include anthropology, linguistics, neuroscience (the study of the brain and nervous system), and artificial intelligence. Cognitive neuroscience, or neurocognition, combines cognitive psychology and neuroscience. Cognitive psychology is sometimes confused with cognitive therapy, a type of psychotherapy used to treat depression and other mental disorders. Cognitive therapy falls within the realm of clinical psychology, the branch of psychology devoted to the study and treatment of mental disorders. See Psychotherapy: Cognitive Therapies. II ORIGINS OF COGNITIVE PSYCHOLOGY Curiosity about the nature of knowledge and the mind dates back as far as the first recorded philosophers. The Greek philosopher Plato held that the seat of knowledge was in the brain, but his pupil Aristotle believed that knowledge was located in the heart. Many others since have wondered about how we come to know and understand our world, how we remember or represent information about the world, and how we arrive at decisions. A Early Studies of Cognition Although Renaissance philosophers and theologians actively debated the source of knowledge and the nature of sense perception (see Epistemology), the scientific study of cognition did not begin until the late 19th century. In 1879 German physiologist Wilhelm Wundt founded the first psychological laboratory, at the University of Leipzig in Leipzig, Germany. Reasoning that people are the best source of information about their own thoughts, Wundt set about studying consciousness through the method of introspection. This technique involved asking people to observe and report what occurred in their minds as they engaged in various mental tasks. In 1885 German psychologist Hermann Ebbinghaus conducted the first experiments on memory and forgetting. In the United States, psychologist William James used introspection to theorize about the structure of memory and consciousness, and in 1890 he defined psychology as "the science of mental life." In 1896 American psychologist Mary Whiton Calkins invented an important technique for studying memory retention. B The Shift to Behaviorism In the early 1900s, however, with psychology becoming more distinct from philosophy and physiology, attention shifted away from questions about mental life to questions about behavior. This shift occurred because many psychologists thought that it was impossible to study mental life using scientific methods. For example, critics of introspection labeled it subjective and speculative, and even its supporters found that people were unable to report on their own mental states in much detail. Behavior, on the other hand, could be observed, measured, and documented. American psychologist John B. Watson, considered the founder of behaviorism, contended that all human behavior could be explained without reference to a person's thoughts, feelings, or mental states. Another leading behaviorist, American psychologist B. F. Skinner, was adamant in his belief that even the most advanced forms of human learning, such as language acquisition, could be explained in terms of the basic principles of conditioning (see Learning). C Reemergence of Cognitive Psychology Landmark developments in the late 1940s and throughout the 1950s revived hope for the scientific study of mental life and fueled a "cognitive revolution" in psychology. In 1949 Canadian psychologist Donald O. Hebb published pioneering work, based in part on animal studies, that theorized about the biological basis of memory and other psychological phenomena. In 1956 American psychologist George Miller showed that there are limits to the amount of information that people can hold in short-term memory at any one time. In the late 1950s American linguist Noam Chomsky refuted Skinner's behaviorist explanation of language development as overly simplistic. Chomsky's theory, which proposed that children possess an innate ability to extract meaning from speech sounds, stimulated further interest in cognitive psychology. D Cognition as Information Processing The development of digital computers introduced new metaphors for thinking about human mental operations. Philosophers had offered such mechanical metaphors many times before, likening the mind to a blank slate (tabula rasa), a black box, and even a mechanical robot. But the computer metaphor was more powerful because it provided both a way for psychologists to conceptualize their observations and a common language for theorists to communicate their ideas. Computer terms such as input, output, processing, information storage, and information retrieval seemed to resemble the "real" mental activities of people. Thus, cognitive psychologists began describing humans as information processors. The information-processing model sees human cognition as a series of stages through which information passes sequentially. In this model, information gets into our brain (is encoded), is retained briefly or for longer periods of time (short-term or long-term storage), and is later reactivated (retrieved) for further processing or use. With the development of more-sophisticated computer systems in the 1980s and 1990s, cognitive psychologists extended the computer metaphor to new models of cognition. These models rejected the idea of information processing as linear and sequential and instead proposed that the brain is capable of parallel processing, in which multiple operations are carried out simultaneously. One such model, called the parallel distributed processing model of cognition, reflects findings in neuroscience that suggest linear processing cannot account for the recorded speed of human memory retrieval. Although the information-processing model is a powerful tool for guiding the study of cognitive processes, many psychologists argue that it falls short of capturing the full richness of people's cognitive experiences. Describing the act of remembering as a process of storage and retrieval, for example, neglects the subjective experience of remembering. Another criticism is that information-processing theory may not reflect how the brain actually works. Newer models, such as the parallel distributed processing model, try to address this criticism by drawing on studies of brain structure and function. Psychologists continue to debate the adequacy of the informationprocessing model, but its influence likely will last well into the 21st century. III METHODS OF RESEARCH Like other psychologists, cognitive psychologists use a wide variety of research methods. Methods particularly relevant to cognitive psychology can be organized into three general categories: (1) self-reports, or people's descriptions of their experiences; (2) reaction-time measurements; and (3) methods that measure biological factors such as brain activity. A Self-Reports One way of researching cognition is to conduct experiments in which the participants are asked to report their experiences. For example, an experiment on pattern recognition might present people with various visual stimuli and ask them to name what they see. An experiment on memory ability might require participants to view a list of words, then either say what they can remember (recall) or select the words they saw from a larger list (recognition). Self-report measures sometimes include people's descriptions of their own intuitions about how their minds work. For example, people might report on the mental imagery they experience as they listen to a story or to music. B Reaction-Time Measurements One common way that psychologists study thinking and other cognitive processes is to measure how fast people can make decisions, solve problems, and distinguish between different stimuli. In typical laboratory studies, people might be asked to name the colors in which words are printed, to scan for a special character in an array of letters, or to respond as quickly as possible about whether statements are true or false. For a demonstration of how reaction times can illustrate mental processes, look at the accompanying illustration, entitled "Stroop Test." First, look at the left side of the illustration and, beginning with the first column, name aloud each color as fast as you can. Next, look at the right side of the illustration and again name the colors in which the words are printed as fast as you can. Did you take longer to finish the second task? Almost all people find that the words interfere with their ability to name the colors. People do not need to read color names before naming the printed colors, but they seem unable to stop themselves. This test suggests that reading is an automatic process and that processing the word meanings interferes with the task of color naming. Computers allow psychologists to measure reaction time in very small units, typically in milliseconds (thousandths of a second). For example, experiments have shown that people can recognize some faces in about 300 milliseconds, or less than one-third of a second. Such precise measurements allow scientists to test hypotheses about how the brain processes, stores, and retrieves information. C Biological Methods Advances in medical technology have made possible some of the most exciting developments in the history of cognitive psychology. Prior to the 1970s, it was virtually impossible to measure the activity of the living human brain without cutting open the head. The invention of sophisticated brain imaging techniques means we can now view pictures of the brain "in action." These techniques include computed tomography (CT), positron emission tomography (PET), magnetic resonance imaging (MRI), and functional magnetic resonance imaging (functional MRI). By observing patterns of brain activity as a person engages in various mental activities, researchers have gained new insights into memory, perception, language, and other processes. For more information about brain imaging techniques, see Brain: Brain Imaging. Scientists use a number of other methods to measure brain and nervous system activity. Scalp electroencephalography (EEG) measures the general electrical activity of the brain by means of electrodes taped to the scalp. Researchers have found that certain EEG readings correlate with particular states of consciousness, such as arousal, relaxed wakefulness, sleep, and deep sleep. Another technique, electrooculography, measures the movements of the eyes and is often used in studies of sleep and dreaming. Studies of cognitive processes in animals may use invasive research methods, such as stimulating parts of the brain with a probe or removing part of the brain. For an overview of biological methods used in psychological research, see Biopsychology: Methods of Research. IV TOPICS OF STUDY One of the broadest branches of psychology, cognitive psychology encompasses dozens of topics of study. This article briefly describes some of the most important areas in the field: perception, learning and memory, thinking and reasoning, and language. A Perception Studies in perception try to understand how people interpret sensory information to make sense out of their world. The human sense organs receive information about the world in the form of physical energy--for example, light waves and sound waves. This energy is converted by our sensory system into electrical impulses that travel to the brain. Perception is the mental process that translates these impulses into things we can recognize and understand: people, objects, places, sounds, tastes, and smells. Perception is such a natural, effortless process that most people are not even aware of it. But to cognitive psychologists, perception is one of the great mysteries of the mind. They wonder about questions such as "How do we perceive the world in three dimensions even though the images projected into the eyes are two-dimensional?" "Why do we perceive melodies in music, rather than a series of disconnected notes?" "What causes visual illusions?" One area of study in perception is pattern recognition, the ability to recognize familiar forms in a sea of sensory information. For example, recognizing a friend's face in a crowd is a form of pattern recognition. Another area of interest in perception concerns the difference between perceiving and imagining. Some cognitive psychologists propose that perceiving and imagining are often quite similar, but others disagree with this point of view. See Perception; Illusion. B Learning and Memory Many people think of learning as something that occurs in a classroom. To psychologists, the word learning refers more generally to how we acquire knowledge, develop new behaviors, and adapt to life's challenges. Researchers have discovered many general principles that govern basic learning. For example, two common forms of learning are operant conditioning (the shaping of behavior through reward and punishment) and learning through observation. Cognitive psychologists are particularly interested in complex forms of learning, such as learning languages or advanced mathematics. Learning is tightly interwoven with memory, the process of storing and retrieving information in the brain. Memory plays a central role in nearly all mental activities. More than just a fact-retrieval system, memory allows us to make inferences, solve unfamiliar problems, and relate objects and events to prior knowledge. Memory is one of the most active areas of research in cognitive psychology. Researchers investigate questions such as, What is the capacity of memory? Why do people forget information? What parts of the brain are involved in memory? How is knowledge represented and organized in memory? What factors influence the accuracy of memories? Most psychologists distinguish at least three systems or components of memory. The first is sensory memory, in which information is held by the sensory system for only an instant. Working memory, also called short-term memory, holds information in consciousness temporarily for immediate manipulation and use. Long-term memory is what most people think of as memory. It stores immense volumes of information for long periods of time. See Learning; Memory. C Thinking and Reasoning Thinking involves the mental manipulation of information for the purpose of reasoning, solving problems, making decisions and judgments, or simply imagining. Although cognitive psychologists cannot see thinking processes, they can make inferences about these processes from behavior. Cognitive psychologists have noted that people use a number of strategies when reasoning about a problem or decision. Often people employ deductive reasoning or inductive reasoning, two forms of logic. In deductive reasoning, people draw conclusions about specific cases from general principles that are assumed to be true. In inductive reasoning, people infer a general rule from specific cases. When making judgments or solving problems, people also frequently rely on heuristics, rules of thumb that usually lead to the correct solution but are not guaranteed to work all of the time. Many philosophers have asserted that humans are rational thinkers who are careful and systematic in their evaluation of information. But when cognitive psychologists look carefully at the kinds of decisions people make and how they arrive at those decisions, they find that people are often less than rational. For example, imagine that you have a serious tropical disease and must decide whether to have surgery or take medication. The medication, while not particularly dangerous, is also not extremely effective. The surgery is very effective, but there is 30 percent chance that you will die within six months after the surgery. Given this hypothetical scenario, most people choose the medication. But when the risk is phrased another way--that 70 percent of those who select surgery are still alive six months later--people are more willing to choose the dangerous procedure. The term framing effects refers to the fact that people's decisions are heavily influenced by the way information is framed. One focus of research in decision making is how to help people avoid these effects when making difficult or life-threatening decisions. D Language Of all human abilities, language is perhaps the most impressive. In spoken, written, and gestured forms, language is the primary means of communication among people. Although other animal species have evolved sophisticated systems of communication, none of these systems approaches human language in complexity. With language, we can refer to events or ideas in the past or future, talk about abstract concepts such as morality, and record the stories of human civilization. Language is a central topic of study in cognitive psychology because it is closely connected with perception, memory, thinking, problem solving, and other mental processes. Of particular interest to psychologists is how children acquire language and why they have an easier time mastering language than adults who try to learn a second language. Many scientists believe the human brain is uniquely "wired" to learn language during a critical period in infancy and early childhood. Supporters of this idea note that children all over the world achieve specific language milestones at roughly the same age. However, scholars continue to debate how much of language capacity is inborn. Another widely debated question is whether animals other than humans have the capacity for language. Researchers have tried to answer this question by training chimpanzees and gorillas--the closest genetic relatives of the human species--to use sign language or to press symbols on a keyboard. This research has shown that apes can produce and understand simple phrases and sentences and even appreciate subtle differences in word order and sentence structure. One chimpanzee, Kanzi, has demonstrated the ability to understand spoken English sentences at the level of a 2y-year-old child. Although some scientists remain skeptical of these findings, most now agree that apes can attain a rudimentary form of language. Other areas of research include the structure of language, how language is organized and represented in the mind, how we process and understand language, the neurological basis of language, and language disorders. Another subject of investigation concerns the relationship between language and thought. For example, is thinking merely speech that is not vocalized, or are other processes involved? How does language influence the way we think? Psycholinguistics is the interdisciplinary study of the mental processes involved in language acquisition, production, and comprehension. Specialists in this field may come from one of various disciplines, including cognitive psychology, linguistics, neuroscience, and anthropology. See Language. Contributed By: Mary Ann Foley Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.