Extra Credit Opportunity On-line study: Print out and give Dr. Carrier copy of e- mail reply that you get from doing the study

Chambers & Reisberg (1985) people memorized figure similar to one below

procedure Next, from memory, people recall the image, and say what it is –People either say duck or rabbit Next, people asked to reinterpret image from memory –Predictions: analog theory  people should have no problem reinterpreting –Propositional theory  people shoud not be able to reinterpret

results None of the Ss able to reinterpret the image from memory Next, had Ss look at the figure –Then, Ss able to reinterpret ambiguous figure (figure that has two or more interpretations) Supports propositional approach

Brooks (1968) P. 201 in textbook First, Ss shown an outline figure (e.g., the letter F in textbook) Then, Ss mentally imagine going around the figure, visiting every corner, deciding whether it is an outside corner (Yes or No)

2 response conditions Manual response: point to a YES or a NO on a sheet of paper for each corner Verbal response: say out loud YES or NO If we have a true visual image, then expect manual response to interfere with doing the task (i.e., the Brooks task) –Further, expect manual responses to be slower than the verbal responses

Results Found manual response to interfere with the task  supports use of visual images (visual code) Supports analog theory

Shepard & Metzler (1971) Sometimes referred to as “mental rotation” experiment P. 197 in book 3-d block figures – 2 shown at a time, side by side As quickly as possible, S decides if two figures represent different views of the same object (speeded task) (yes-no)

more In book, p. 197 –Figure 7.10 (A) : same object so YES –(B): YES, same object –(C): NO, different objects Original hypothesis: that people use visual images to do task – mentally rotate one picture to see if it lines up with the other

results Prediction: if people use visual images and rotate one image to line it up with the other, then –The larger the difference in angle between two views of same object, then the longer it should take to respond YES Results: RTs supported the prediction, thus analog theory

summary Some experiments support analog theory; others support propositional theory

Organization of memories Categorization – forming or having categories of memories –Category = related set of memories/items –Members/exemplars/examples = actual items in category

Example category Category of Furniture Rosch & Mervis (1975): Ss asked to say typical items of furniture; then Es combined Ss response to see average categories (Table 8.5, p. 233) Furniture: 1. Chair; 2. Sofa; 3. Table; 4. Dresser; 5. Desk 16. Clock; 17. Picture; 18. Closet; 19. Vase; 20. Telephone

What constitutes typicality? Family resemblance: some members of a category look more like the rest of the examples than other members do An “attribute”: a feature of an item –E.g., attribute of a chair is that you sit on it –E.g., sofa has cushions Ss were asked to list all of the attributes of all of the members of the category

More from Rosch & Mervis Then, Es add up all of the attributes that each member shares with the other members of the category –E.g., how many attributes of a chair are shared with the other furniture category members? Higher numbers  high family resemblance; lower numbers  low family resemblance

Results & interpretation Results: family resemblance scores were significantly correlated with typicality ratings Interpretation = categories are organized based on the number of shared features amongst members (family resemblance)

Hierarchical organization of categories Rosch and colleagues “natural” categories: categories that occur in everyday life 3 levels: (Table 8.4, p. 230) –Superordinate (highest level) (e.g., furniture) –Basic (middle level) (e.g., chair) –Subordinate (lowest level) (e.g., easy chair) Typicality reflects family resemblance at all levels