8.1 The Organization of Knowledge A concept: is the mental representation of an object, event or idea Psychologists use the terms categories to refer to these clusters of interrelated concepts. Categorization is difficult to define in that it involves elements of perception The earliest approach to the study of categories is referred to as classical categotization: this theory claims that objects or events are categorized according to a certain set of rules or by a specific set of features Classical categorization does not tell us the full story of how categorization works. However, we use a variety of cognitive processes in determining which object fit which category One of the most major problems we confront in classical catgegorization is graded membership Graded membership: the observation that some concepts appear to make better category members than others Sentenceverification technique: in which volunteers wait for a sentence to appear in front of them on a computer screen and respond as fast as they can with a yes or no answer. Prototypes: Categorization by comparison Prototypes: are mental representation of an average category member. (what comes to mind in your head when you think of a bird) Prototpes allow for classification by resemblance. The main advantage of prototypes is that they help explain why some category member make better example than others. Networks and Hierarchies Semantic network: an interconnected set of nodes (or concpets) and the links that join them to form a category In these networks, similar items have more and stronger connections than unrelated items. These connections explain why it is easier to identify one member of a category Nodes: are circles that represent concepts and links connect them together to represent the structure of a category as well as the relationships among different categories. Hierarchies are important in organization because different levels for the category are useful in different situations. Basic Level Categories: The terms used most often in conversation They are the easiest to pronounce They are the level at which prototypes exist They are the level at which most thinking occurs Working the Scientific Literacy Model Domain specific hypothesis: researchers proposed that evolutionary pressures lef to the development of specilaized circuts in the brain for a small group of categories that were important for our surivival. One weakness of this view is that it doesnt take into account peoples different experiences with each category.