Cognitive Psychology PDF

serial bottlenecks: Psychologists have proposed that there are serial bottlenecks in human information processing, points at which it is no longer possible to continue processing everything in parallel. Example: Although most of us can perform separate actions simultaneously when the actions involve...

serial bottlenecks: Psychologists have proposed that there are serial bottlenecks in human information processing, points at which it is no longer possible to continue processing everything in parallel. Example: Although most of us can perform separate actions simultaneously when the actions involve different motor systems (such as walking and chewing gum), we have difficulty in getting one motor system to do two things at once. where the bottlenecks in information processing lie? Various theories about when they happen are referred to as early- selection theories or late-selection theories, depending on where they propose that bottlenecks take place. Wherever there is a bottleneck, our cognitive processes must select which pieces of information to attend to and which to ignore. Attention: attention is concerned with where these bottlenecks occur and how information is selected at these bottlenecks. Example: imagine ourselves at a Museum, looking at a painting. First, our eyes will catch the large, salient objects. This is an instance of stimulus-driven attention. Second step is that we have a goal and will direct our attention over the picture to find the object being described. Now imagine that we hear an alarm system starting to ring. A stimulus-driven factor has intervened, and our attention will be drawn away from the picture and switch to the adjacent room. Goal-directed attention versus stimulus-driven attention Neural imaging evidence suggests that the goal-directed attentional system is more left lateralized, whereas the stimulus-driven system is more right lateralized. The prefrontal regions of the brain (dorsolateral prefrontal cortex, anterior cingulate) are particularly important in executive control. MEMORY FOR MEANINGFUL INTERPRETATIONS OF EVENTS: If you show the Participants different pictures and ask them about their differences, they are more sensitive to meaning-significant changes in a picture and not for details in the picture. This is not because they are incapable of remembering such detail, but rather because this detail does not seem important and so is not attended. When people see a picture, they attend to and remember best those aspects that they consider meaningful. Multimodal Hypothesis vs. Amodal Hypothesis: Multimodal hypothesis: we have various representations tied to different perceptual and motor systems and that we have means of directly converting one representation to another. Example: the double-headed arrow going from the visual to the motor would be a system for converting a visual representation into a motor representation and a system for converting the representations in the opposite direction. Amodal Hypothesis: According to this hypothesis, we have systems for converting any type of perceptual or motor representation into an abstract representation and for converting any abstract representation into any type of perceptual or motor representation. So, to convert a representation of a picture into a representation of an action, one first converts the visual representation into an abstract representation of its significance and then converts that representation into a motor representation. About the previous example (differences of the photos), we can say that the amodal hypothesis holds that this information is retained in the central meaning system. The multimodal hypothesis holds that the person has converted the information from the modality of the presentation to some other modality. Categorization: Categorization simplifies perception and cognition related to the social world by detecting inherent similarity relationships or by imposing structure on it (or both). Research on categorization has focused both on how we form the categories in the first place and on how we use them to interpret experiences. It has also been concerned with notations for representing this categorical knowledge. For instance, if you tell someone, "I was licked by a dog;' your listener can predict the number of legs on the creature, its approximate size, and so on. The effects of such categorical perceptions are not always positive-for instance, they can lead to stereotyping. Semantic Networks: people store information about various categories such as canaries, robins, fish, and so on-in a network structure. we represent a hierarchy of categorical facts, such as that a canary is a bird and a bird is an animal, by linking nodes for the two categories with isa links. If our categorical knowledge were structured like Figure 5.10, we would expect sentences in level 1 to be verified more quickly than sentence in level 2, which would be verified more quickly than sentence 3. (Because we need to check the lower level of the information) The following statements about the organization of facts in semantic memory and their retrieval times seem to be valid conclusions from the research: I. If a fact about a concept is encountered frequently, it will be stored with that concept even if it could be inferred from a higher order concept. 2. The more frequently a fact about a concept is encountered, the more strongly that fact will be associated with the concept. The more strongly facts are associated with concepts, the more rapidly they are verified. 3. Inferring facts that are not directly stored with a concept takes a relatively long time. Schemas: Semantic networks, which just store properties with concepts, cannot capture the nature of our general knowledge about a house, such as its typical size or shape. Schemas represent categorical knowledge according to a slot structure, in which slots are attributes that members of a category possess, and each slot is filled with one or more values, or specific instances, of that attribute. Example: House Isa: building Parts: rooms Materials: wood, brick, stone In this representation, such terms as materials and shape are the attributes or slots, and such terms as wood, brick, and rectilinear are the values. Each pair of a slot and a value specifies a typical feature. Values like those listed above are called default values because they do not exclude other possibilities. For instance, the fact that houses are usually built of materials such as wood, brick, and stone does not mean that something built of cardboard could not be a house. If we know something is a house, we can use the schema to infer that it is probably made of wood, brick, or stone and that it has walls, windows, and ceilings. Schemas have another type of structure, called a part hierarchy. (Like the photo in the previous page) Psychological Reality of Schemas: Here we had an example that was about an experiment room, and 30 participants that were asked to recall the items in the room, after being 35 seconds in the room. 29 of the 30 participants recalled that the office had a chair, a desk, and walls. Their recall was strongly influenced by their schema of what an office contains. Only 8 participants, however, recalled that it had a bulletin board or a skull. On the other hand, 9 participants recalled that it had books, which it did not. (They falsely recalled items that are default values of the schema but were not in this office.) we see that a person's memory for the properties of a location is strongly influenced by that person's default assumptions about what is typically found in the location. A schema is a way of encoding those default assumptions. Degree of Category Membership: One of the important features of schemas is that they allow variation in the objects associated with a schema. Example: apples are seen as fruits more rapidly than are watermelons, and robins are seen as birds more rapidly than are chickens. Failing to have a default or typical value does not disqualify an object from being a member of the category, but people's judgments about nontypical objects tend to vary a great deal. although participants did agree on some items, they disagreed on many. For instance, whereas all 30 participants agreed that cancer was a disease and happiness was not, 16 thought stroke was a disease and 14 did not. In the following photo, it was asked from the participant of an experiment to give a rate(response to a fex photos of dishes and asked which one is a cup? Their answers depend on the depth of the cups. Results from this experiment demonstrating that the cup category does not appear to have clearcut boundaries. The percentage of participants who used the term cup versus the term bowl to describe the objects shown in the above figure is plotted as a function of the ratio of width to depth. The solid lines reflect the neutral context condition, the dashed lines the food-context condition.