PSY 200 1st Edition Lecture 14 Current Lecture Knowledge Knowledge Representation Based on meaning rather than true physical forms We can think of knowledge as a categorization system Categories are very important to our mental life We tend to categorize everything Categories help us understand our world allow us to make predictions allow us to more easily understand novel objects situations you always work with the same six people provide a great deal of information about an object situation Categories and Exemplars We classify the objects we encounter into categories A class of objects with common attributes features and are said to have a family resemblance The members of a category are called exemplars Some Exemplars are Better than Others The typicality effect Smith et al 1974 Measured by speed of sentence verification participants must verify if the sentence is true or not Theories of categorization must account for the typicality effect which is very strong and reliable Definitional Approach Objects that meet a particular set of criteria definition are placed in a category Way more difficult for most types of categories Also definitional approaches have difficulty accounting for data on the typicality effect Prototype Approach Store a prototype of the category an average of all the members of the category Assumes that people compare the exemplar to the prototype Naming Effect These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Objects that match the prototype usually named first Suggests a strong association between category and prototypical exemplars Priming Effect Faster with perceptual decisions that match prototype Problems Can t explain the variability within a category Must have information about all different types rather than just ONE example Exemplar Theory Within each store is an example you have encountered Categorize by comparing whatever example you have that comes easily to mind Explains typicality effect You are faster at classifying things that are more like exemplars you have Not as economical as prototype theory because you have to store so many exemplars Which Theory is Right Definitional Approach not much merit Prototype and Exemplar Approaches kay be right but used in different conditions