BHS 499-07 Memory and Amnesia

1. BHS 499-07Memory and Amnesia Semantic Long-Term Memory

2. Semantic Memory • Semantic memory is general knowledge of the world. • Are dogs safe? • What happens in a restaurant? • Generalizations that can apply to a variety of situations – built from previous experiences.

3. Semantic Priming • Priming – thinking about one concept brings related memories closer to awareness. • People respond faster to a concept after it has been primed. • The prime comes first, then the target (associated item), and response times (RTs) are measured.

4. Memory Structure • Semantic memory is structured based on shared meaning, not prior associations. • Similar concepts in terms of meaning are stored closer to each other. • Semantic “closeness” is metaphoric, based on response times. • Activation spreads to related items. • A great deal of repeated use moves items from episodic to semantic memory.

5. Controlled Priming • In general, priming is automatic (does not require conscious effort). • Conscious expectations can change priming (Neely). • In the Category Shift Expected condition, the prime signaled the appearance of a different category which was then primed. • It took a while for the different expectation to develop so priming occurs after several trials.

7. Mediated Priming • How far does activation spread during priming? • Lion  Tiger  Stripes • Does activation spread to Stripes via Tiger? • This phenomenon is called mediated priming – smaller than regular priming. • The further you go from the original prime, the smaller the activation and less likely the priming.

8. Semantic Interconnectivity • No fan effect in semantic memory – more associations speed up, not slow down retrieval. • Direct and indirect connections provide more ways to retrieve info, making it more reliable. • As with episodic memory, inhibition occurs, but mostly during active retrieval, not when passively reading.

9. Semantic Memory is Embodied • In addition to capturing abstract relationships among words, storage reflects how we relate to the world. • Concrete nouns tend to activate the sensory cortex because they are things we see and feel – perceptual effort. • Verbs tend to activate the motor cortex because they are things we do.

10. Categorization • Similarity-based grouping in which two or more entities are treated as equivalent. • Concept – a mental construct that contains information associated with an idea (a dog). • Category – a class of concepts to which a set of assertions applies (a dog has four legs, may bite). • Categories are generalized from repeated instances of concepts.

11. Properties of Categories • Levels of categorization: • Basic, subordinate (detailed), superordinate. • We operate on the basic level most often – items on that level retrieved better & faster. • Central tendency – there is an averaged ideal or best member of the category. • Graded membership – some members are better than others (robin vs penguin)

13. Definition of the Category • Categories are defined in different ways: • Rules – things that are used at the beach, numbers divided by 2, kinship (bachelor). • Shared features or family resemblance – birds, furniture. • Categories defined by rules or specific features are called classical categories. • Classical theories don’t explain graded membership and typicality effects.

17. Prototype Theory • Categories based on similarity or shared features may arise inductively from unconscious mental statistics. • The typical member may be a statistical average of all category members, called a prototype. • This theory does not explain how categories change over time or how we know their extent. • Caricatures emphasizing distinctive features are better for comparing across categories.

19. Exemplar Theory • Rather than reasoning from a derived prototype, we use all category members to make decisions. • Explains sensitivity to context effects (priming of pony mane greater than lion’s mane). • Circularity is a problem • How can members define a category if the category is needed to identify the members?

20. Explanation-Based Theory • When a category is formed, people try to explain why its members go together. • Why do wings and feathers go together? Feathers help creatures to fly. • Ad hoc categories – explanations created for a group of objects (e.g., things that stink). • Psychological essentialism – the items grouped form natural kinds based on their nature, pragmatics, or causality (purpose).

21. Stereotypes & Prejudice • Stereotypes are categories for various groups of people. • When use of a stereotype causes someone to treat an individual inappropriately that is prejudice. • Use of stereotypes is natural and part of normal thinking, but we must monitor our use of them for fairness.

22. Ordered Relations • Semantic Distance Effect – the time it takes to make a judgment is proportionate to their distance. • Semantic Congruity Effect – items are easier to judge when they are similar with respect to some dimension. • Serial Position Effect – items at either end are easier to judge than the middle.

23. Schemas & Scripts • Commonly experienced aspects of life form schemas – these make it easier to understand new situations. • What happens at a birthday party? • What happens at a restaurant? • Scripts are schemas with a sequence of events that occur in a stereotyped fashion. • Organized in time, like a script for a play or TV show.

24. 5 Primary Schema Processes • Selection – which components are important and which are peripheral. • Knowing what schema to apply to a situation tells you what to pay attention to (Droodles). • Ambiguous passages are clarified by schemas (washing clothes). • Abstraction – the surface form is converted to an abstract meaning. • Drawings change in the direction of meaning.

26. Schema Processes (Cont.) • Interpretation – We infer missing info during reading or movies based on the schema (e.g., on/off airplane, infer flight) • Integration – When we receive info piecemeal, the schema lets us put it all together (e.g., mysteries). • Reconstruction – fill in gaps at recall from schema (War of the Ghosts).

27. Scripts • Temporally ordered schemas structured by the main components of the event. • Preference for going in the forward order. • It takes longer to read a script when the next step is further along in sequence. • People scan the steps in the script. • Even when parts are presented in random order they are remembered in proper order.

28. Limits on Schema Use • Schemas are not always used. • Causes may be inferred from schemas but not necessarily effects because a number of outcomes may be possible. • When a schema is discredited, people will ignore it. • Escaped convict/deer hunter schema changed when subjects were told the title was wrong – fewer schema-related intrusions.

30. Semantic Illusions • How many animals of each kind did Moses take on the ark? • 81% of UCSD students got this wrong. • What was the famous line uttered by Louis Armstrong on the moon? • 3 explanations: (1) general focus; (2) partial assessment; (3) similar language components giving illusion it is known.

32. Naïve Physics • A semantic illusion of nonverbal memory. • Mental models of how the world works do not conform to real life physics. • Similar to Medieval theories of motion. • Less likely to occur with moving models, more likely with static drawings. • People set thermostat higher so it will heat the house faster – temperature accelerator. • Vision involves emissions from eyes.