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Study Notes 2.docx

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Lawrence Murphy

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Ian Shaughnessy Cognitive Psychology Feb 7 2013 Chapter 5 Object Recognition – the process whereby we match an incoming stimulus with stored representations for the purpose of identification. (identifying and classifying what it is we have latched on to) Rosh (1976) Levels of Categorization – also known as gradations of specificity that can be used in describing everyday categories. 3 levels (ie animal, bird, black-winged chickadee) i) Super ordinate level of categorization – animal is the most general ii) The midpoint (Basic level of categorization) – bird iii) The subordinate level – black-winged chickadee. Is the most specific -Rosh says that the middle level dominates our cognitive processing Entry point for recognition – the default level of categorization that we use for familiar objects We use both bottom-up and top-down processing for recognizing objects -When an object is obstructed, we rely on our knowledge, expectations, and surrounding contexts to supplement the data (ie top-down) -Bottom-up is how we identify objects from past data and experiences Study by Palmer, Rosch, and Chase (1981) on the perspective effects of cognition -Participants were given a number of pictures of objects -One group had to rate how well each picture represented the object -The other group had to indentify the objects as fast as possible -Recognition turned out to be fasted for pictures rated higher by the first group Study by Biederman and Gerhardstein (1993) -Suggested that orientation might not matter at all that much in object recognition -Used a technique called priming: a gained benefit from an earlier exposure to a stimulus -Presented an image of a flashlight to participants in Phase 1 and identify it -Phase 2 had participants identify the same image either the same way or rotated or a similar image in the same way or rotated -Phase 1 was very slow but all examples of phase 2 were faster -This means that seeing the flashlight for phase 1 (or any object) primed identification of all flashlights. This is called Semantic Priming -Object rotation did not have a significant enough effect on object recognition Study of the effects of context in object recognition by Palmer (1975) -Most studies of objected recognition were in isolation that did not have meaningful context -Sketches of everyday scenes were presented and then sketches of single objects were presented for identification -The relationships varied between the scene and the objects -Some scenes were consistent with the object being presented (kitchen followed by loaf of bread) -Some scenes were inconsistent with the object (kitchen followed by a drum) -Some scenes were inconsistent and misleading (mailbox that has features similar to bread loaf) -Identification of objects were best when the scene was consistent with the object Study of the effects of context in object recognition by Davenport and Potter (2004) -Had participants look at a scene followed by a pattern made to erase the just-observed stimuli called a mask. -Participants were able to identify what was in the foreground better than the background -Participants were also able to identify even better if the foreground image was consistent with the background. (ie football player was identified better if he was in a field rather than a church) Theories of Visual Object Recognition 1. Parts-Based Approaches - Incoming patterns are parsed into component parts (ie bunny: little sphere, big sphere, long thin triangles) -We then compare these components to information in our memory and recognize that this basic set of components in this particular combination equals a rabbit 2. Image-Based Approaches -More holistic process -We take the whole image and compare it to corresponding representations in the memory until we find a match. Parts-Based Approach in More Detail -The orientation of the features of the object do not matter: Viewpoint-Invariant Recognition by Components (RBC) -A parts-based theory proposed by Biederman (1993) -The features which we identify from objects are three dimensional shapes called geons -There are 36 geons which serve as visual primitives- simple shapes that form into more complex shapes -The geons can be viewed the same way regardless of orientation -Stages of RBC object orientation 1. Edge extraction – looking for differences in features (colour, texture, luminance) 2. Search for non-accidental features – features that don’t appear to be an accident 3. Parsing the object in the simplest way possible 4. Geons determined; match with memory representations 5. Object identified Tarr and Pinker Study (1989) Arguing that sometimes perspective affects recognition - Presented participants with 3 abstract shapes - Presented in same orientation until memorized - Results showed that if rotated, participates had a harder time identifying objects - “Viewpoint dependence” Image-Based Approach (IB) - Objects are recognized by comparing the input with a stored replica -View-point dependent Template Matching -Exact match must be found -Fails to account for the flexibility of object recognition Chapter 6 Types of Long Term Memory Declarative Memory -Is a long term memory system responsible for retention of factual information about the world, as well as personally experienced episodes. -Tulving (1972, 1983) believes that declarative memory is divided into two kinds of memory 1. Episodic Memory – referring to one’s memory for personally experienced events that include contextual elements like the time and place of the event’s occurrence. -Example would be remembering when you won a baseball game 2. Semantic Memory -refers to knowledge or information about our world that does not include contextual elements like the time and place or place the information was learned. -Example would be when the declaration of independence was signed in 1776 Characteristic Episodic Semantic Likelihood of forgetting High Low Usefulness Low High Recollective Experience Present Not Present Sensory Component Present Not Present Presence of emotion Present Not Present Procedural Memory -Declarative Memory is “knowing that” and Procedural Memory is “knowing how” -Examples of procedural memory include skills (tying one’s shoe, swinging a golf club) and the formation of simple associations (like a classically conditioned taste aversion) -Harder to forget (never forget how to ride a bike) Descriptive Framework -Melton (1963) says that remembering can be characterized in three stages 1. Encoding – The processes involved in the acquisition of material 2. Storage – Formation of a memory representation 3. Retrieval – Processes involved in getting information out of memory (when you have a question and you say to yourself “I know this, but I can’t think of the answer right now” this is a retrieval failure) Implicit Memory Tests (direct memory tests) -Involve conscious recollection of some specific event from the past -Types: -Free recall -Cued recall -Recognition -Performance is measured by accuracy Implicit Memory Tests (indirect memory tests) -Recollection in the absence of conscious awareness -Types: -Word Stem Completion (Gar_ _ _) -Word Fragment Completion (G_a_l_c) -Performance is measured by priming or the benefit in performance from previous exposure to a word. -As an example, a research has two word lists (List A and List B) ½ of participants study the words from list A and the other half study list B. Then the researcher asks participants to complete word fragments containing words from both lists. People who studied list A will complete the word fragments from list A better than those who did not and vice versa. Retrospective Memory (RM) Tests -Remembering information from the past (e.g,, explicit and implicit memory tests.) Prospective Memory (PM) Tests -Remembering to perform and action in the future -The intention to act can be triggered in two ways -Event-Based: external event -Time-Based: the passage of time Encoding Processes in Explicit Long-Term Remembering Attention and Repetition Attention -Information must be actively processed in consciousness Repetition -Material that is presented more than once is easier to remember The Spacing Effect -Types of repetition Massed repetition: involves repeated presentations that occur closely together in time Spaced repetition: involves repeated presentations spread out over time Spacing effect: distributed is better than massed Explanations for the spacing effect -Deficient-Processing view -Locus of effect is at encoding -Missed repetition leads to deficient processing of the second presentation of the item -Result is only one fully encoded memory representation of the item -Encoding Variability view -Locus of effect is at retrieval -Massed repetition leads to little variability in the encoded memory representations -Results in representations that will be difficult to locate in a memory search Study by Bahrick (1979, 1984) on how we retain foreign language vocabulary -Participants learned Spanish in high school or college 1-50 years earlier -Had participants complete various tests to assess their Spanish knowledge -The results indicated that even after 25 or more years, people retained a fair amount of information -Retention depended on initial learning -More training = More retention Study by Bahrick and Hall (1991) on students’ retention of material from high school algebra -Assessed retention of material learned in high school algebra -Results showed that grades and SAT were related to overall performance, but unrelated to maintenance over time -Only predictor of maintenance over time was the interval of time over which the information was learned -The longer the interval = the longer the retention Conway, Cohen, and Stanhope (1991) -Assessed retention of material learned in a year-long cognitive psychology course -Results... -Retention of information about general research methods showed no decline over the retention interval The 2 factors in determining the effect of spaced r
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