Lecture 13 – Psyco 350, B1 Winter, 2011 N. R. Brown, U of Alberta Lecture 13 – Psyco 350, B1 Winter, 2011 N. R. Brown Psyco 350 Lec #13– Slide 1 Psyco 350

Implicit Memory & Real-World Estimation Semantic Memory Outline N. R. Brown, U of Alberta Implicit Memory & Real-World Estimation Semantic Memory Network Models Priming Scripts & Schemata Psyco 350 Lec #13– Slide 2 Psyco 350

Brown & Siegler (1992): Method N. R. Brown, U of Alberta Materials: 100 countries Participants: 24 CMU undergrads Tasks: Rate knowledge Estimate population Psyco 350 Lec #13– Slide 3 Psyco 350

Brown & Siegler (1992): Results N. R. Brown, U of Alberta Brown & Siegler (1992): Results Mean Rank-Order Correlations True Pop NYT Index Est Estimated Population .41 .57 Rated Knowledge .37 .70 .58 Important results: As predicted, R(est w/ know) quite high (.58) [R(est w/know) = .58] >> [R(est/true) = .41] Interpretation: pop-estimates based in availability-base intuitions Psyco 350 Lec #13– Slide 4 Psyco 350

Availability & Population Estimation N. R. Brown, U of Alberta Interpretation: pop-estimates based in availability-base intuitions An Alterative Interpretation: People hold preexisting beliefs about the size of well-known countries. These beliefs are biased by media coverage. People infer that unknown countries are small. Psyco 350 Lec #13– Slide 5 Psyco 350

Availability & Population Estimation N. R. Brown, U of Alberta People can and do justify their estimates with reference to task relevant knowledge. Size categories are often mentioned. Comparisons w/ other countries also occur Key question: Are size categories retrieved or inferred? Psyco 350 Lec #13– Slide 6 Psyco 350

Phase 2 – estimate populations Brown, Cui, & Gordon (2002) N. R. Brown, U of Alberta Aim: Determine whether population estimation is sensitive to priming, as Availability account predicts. Method: Phase 1 – rate knowledge 52 countries (primed set) Phase 2 – estimate populations 52 primed countries & 52 unprimed countries* * primed & unprimed sets matched for estimated pop, rated kn, actual pop, actual area & region Psyco 350 Lec #13– Slide 7 Psyco 350

Availability Prediction: Primed > Unprimed Results: Brown et al. (2002): Results N. R. Brown, U of Alberta Availability Prediction: Primed > Unprimed Results: Primed: 23.3 million Unprimed: 21.2 million  2.1 million* %  10% Interpretation: knowledge ratings  availability/fluency in primed set Availability/fluency influenced estimation process Psyco 350 Lec #13– Slide 8 Psyco 350

Another Example: Fatality Estimates N. R. Brown, U of Alberta Task: How many Canadians died of CauseX last year? Results: reasonable correlation between estimated & true fatality rate. Availability Bias: holding true frequency constant, more vivid causes elicit  estimates Psyco 350 Lec #13– Slide 9 Psyco 350

Another Example: Fatality Estimates N. R. Brown, U of Alberta Task: How many Canadians died of CauseX last year? Results: reasonable correlation between estimated & true fatality rate. Availability Bias: holding true frequency constant, more vivid causes elicit  estimates Psyco 350 Lec #13– Slide 10 Psyco 350

Importance of Availability N. R. Brown, U of Alberta Importance of availability differs across tasks. ___________________________________________________________________________________________ Determinants: actual/perceived correlation between propx and memory quantity & credibility of competing information __________________________________________________________________________________________ Psyco 350 Lec #13– Slide 11 Psyco 350

Importance of Availability N. R. Brown, U of Alberta Judgment/estimation tasks that (sometimes) display an availability bias: recency (dates, recognition), truth, fatality rates, frequency, probability, corporate sales, wealth, population Judgment/estimation tasks that do not display an availability bias: age, distance, area, latitude, longitude Psyco 350 Lec #13– Slide 12 Psyco 350

Summary: Implicit Memory & Judgment N. R. Brown, U of Alberta Prior exposure (priming) facilitates subsequent processing (increased fluency). People are sensitive to differences in fluency. Fluency/availability (sometimes) treated as important cue to the value of target property. This happens when: prop x correlates w/ memory other task-relevant information sparse/non-predictive Psyco 350 Lec #13– Slide 13 Psyco 350

Summary: Implicit Memory & Judgment N. R. Brown, U of Alberta Use of fluency/availability in judgment often produces biased performance Reason: many factors impact availability. For example: cultural & physical distance, economic power, & group conflict affect rated knowledge, but do not necessarily correlated w/ actual population Psyco 350 Lec #13– Slide 14 Psyco 350

Semantic Memory: Original Definition N. R. Brown, U of Alberta “Semantic memory is the memory necessary for the use of language. It is a mental thesaurus, organized knowledge a person possesses about words and other verbal symbols, their meaning and referents, about relations among them, and about rules, formulas, and algorithms for the manipulation of these symbols, concepts and relations.” (Endel Tulving, 1972, p. 36) Psyco 350 Lec #13– Slide 15 Psyco 350

Contents of Semantic Memory N. R. Brown, U of Alberta We “know” many, many things: word meanings (< 20K), geography, history, sports, pop culture, genealogy, social relations, biological facts, etc, etc Most of this knowledge: easily & readily accessed decontextualized Psyco 350 Lec #13– Slide 16 Psyco 350

Semantic Memory: Important Issues N. R. Brown, U of Alberta How is complex information… acquired, revised, represented, organized, accessed, manipulated. Some basic elements are understood in a general way. semantic networks spreading activation schemata/scripts Potential building blocks for a more complete understanding of the psychology of complex knowledge. Psyco 350 Lec #13– Slide 17 Psyco 350

Semantic Networks I: Collins & Loftus (1975) N. R. Brown, U of Alberta Semantic memory is organized as a network of interrelated concepts Each concept is represented as a node Concepts are linked together by pathways “Length” of pathways reflects degree of semantic relatedness/ associative strength Concepts close in meaning / highly related (e.g., red, fire) stored close together. Unrelated concepts (red, street) are stored far away Psyco 350 Lec #13– Slide 18 Psyco 350

An Example of a Semantic Network N. R. Brown, U of Alberta An Example of a Semantic Network Psyco 350 Lec #13– Slide 19 Psyco 350

Spreading Activation & Semantic Networks N. R. Brown, U of Alberta Accessed node is a source of activation Activation spreads from source to related nodes. The amount of activation received by a given node is a function of path length. The more active a concept is, the more readily it will be retrieved. Implication: Retrieving a given concept should be easier when it is proceeded by a related concept than when it is not. Psyco 350 Lec #13– Slide 20 Psyco 350

An Example of a Semantic Network N. R. Brown, U of Alberta An Example of a Semantic Network Psyco 350 Lec #13– Slide 21 Psyco 350

Implication of spreading activation account: Semantic Priming N. R. Brown, U of Alberta Implication of spreading activation account: A given concept should be primed – responded to more rapidly/accurately – when it is preceded by a related concept than when it is not. Therefore, lexical decisions should be faster when target preceded by related word than when not. Psyco 350 Lec #13– Slide 22 Psyco 350

Semantic Priming: Meyer & Schvaneveldt (1972) N. R. Brown, U of Alberta An early demonstration of Semantic Priming Task: Lexical Decision -- with word pairs Both items are word  Yes One item is a non-word  No Both items are non-words  No Psyco 350 Lec #13– Slide 23 Psyco 350

Semantic Priming: Meyer & Schvaneveldt (1972) N. R. Brown, U of Alberta Stimuli: Associated word pairs: nurse-doctor Unrelated word pairs: bread-doctor word & non-word: bread-treb non-word & word: treb-bread non-word & non-word: treb-manty Psyco 350 Lec #13– Slide 24 Psyco 350

Meyer & Schvaneveldt (1972): Results N. R. Brown, U of Alberta Main Finding: word-word pairs: associated RT < unassociated RT Psyco 350 Lec #13– Slide 25 Psyco 350

Spreading Activation: N. R. Brown, U of Alberta Spreading activation assumed automatic. Do expectancies affect semantic access? Can activation be control? Psyco 350 Lec #13– Slide 26 Psyco 350

Basic Premises: 2 components to priming Automatic component: Neely (1977) N. R. Brown, U of Alberta Basic Premises: 2 components to priming Automatic component: fast, effortless, unaffected by intention/expectation Controlled component: Attentional, Slow, Effortful, Benefits (if correct) Costs (if incorrect) Psyco 350 Lec #13– Slide 27 Psyco 350

Goal: Contrast automatic & controlled priming Task: Neely (1977) N. R. Brown, U of Alberta Goal: Contrast automatic & controlled priming Task: Lexical Decision -- Timed Word/Non-word Decision Trial: Prime  Target  Response SOA RT SOA = Stimulus Onset Asynchrony Psyco 350 Lec #13– Slide 28 Psyco 350

Expectation X Relation X SOA . No Shift 250 msec Shift 400 msec Neely (1977): Design N. R. Brown, U of Alberta Prime-Target* Expectation X Relation X SOA . No Shift 250 msec Shift 400 msec 700 msec 2000 msec * see next slide Psyco 350 Lec #13– Slide 29 Psyco 350

No Shift Trials: See Bird as prime expect a bird name as target. N. R. Brown, U of Alberta No Shift Trials: See Bird as prime expect a bird name as target. 1. Neutral XXXX -- robin 2. No Shift BIRD -- robin 3. Shift (unexpected) BIRD -- arm Shift Trials: See Building as prime, expect a Body Part as target. 1. Neutral XXXXX -- window 2. No Shift BUILDING -- window 3. Shift (expected) BUILDING -- leg 4. Shift (unexpected) BUILDING -- robin Psyco 350 Lec #13– Slide 30 Psyco 350

No Shift Trials: See Bird as prime expect a bird name as target. N. R. Brown, U of Alberta No Shift Trials: See Bird as prime expect a bird name as target. 1. Neutral XXXX -- robin 2. No Shift BIRD -- robin 80% primed trials 3. Shift (unexpected) BIRD -- arm 20% primed trials Shift Trials: See Building as prime, expect a Body Part as target. 1. Neutral XXXXX -- window 2. No Shift BODY -- leg 10% primed trials 3. Shift (expected) BODY – window 80% primed trials 4. Shift (unexpected) BODY – robin 10% primed trials Psyco 350 Lec #13– Slide 31 Psyco 350

A Priming Effect: Neutral Trials - Primed Trials Neely (1977): Results N. R. Brown, U of Alberta A Priming Effect: Neutral Trials - Primed Trials Two Type of Priming Effects: Facilitation Effects -- Positive Priming Priming effect is positive -- Neutral > Primed Inhibition Effect -- Negative Priming Priming effect is negative -- Neutral < Primed Psyco 350 Lec #13– Slide 32 Psyco 350

Neely (1977) Results – NO Shift Expected N. R. Brown, U of Alberta No-shift, same-category pairs (Bird-robin): Substantial facilitation at all SOA. 2. Shift, different-category pairs (Bird-arm): Inhibition increases with SOA Psyco 350 Lec #13– Slide 33 Psyco 350

Neely (1977): Results – Shift Expected N. R. Brown, U of Alberta 1. Expected Shift (BODY –door): Facilitation increases with SOA 2. No-shift, same-category (BODY -- heart): Facilitation at smallest SOA Increasing inhibition at longer SOAs Psyco 350 Lec #13– Slide 34 Psyco 350

Neely (1977): Results – Shift Expected N. R. Brown, U of Alberta 1. Expected Shift (Building-leg): Facilitation increases with SOA 2. No-shift, same-category pairs (Building-window): Facilitation at smallest SOA Increasing inhibition at longer SOAs 3. Shift to unexpected category (BODY - robin) Inhibition at all SOAs Inhibition increases with SOA Psyco 350 Lec #13– Slide 35 Psyco 350

Neely (1977): An Explanation N. R. Brown, U of Alberta 1. Automatic Spreading Activation: Originates at prime, spreads to related concepts, decays rapidly. 2. Attention required to maintain activation over longer SOAs. Psyco 350 Lec #13– Slide 36 Psyco 350

Neely (1977): An Explanation N. R. Brown, U of Alberta 3. Focusing attention on one category: facilitates (primes) processing of category members interferes with the processing (reading/word recognition) of items from other categories Psyco 350 Lec #13– Slide 37 Psyco 350

Neely (1977): An Explanation N. R. Brown, U of Alberta 4. In the Shift-Expected condition, subjects shift attention to & maintain attention for cued category It takes time to shift attention to new category. Once attention is shifted, focus is on the new category. Psyco 350 Lec #13– Slide 38 Psyco 350

Neely (1977): An Explanation N. R. Brown, U of Alberta Shifting categories takes times. Maintaining focus on indicated category: facilities processing of focal category members reduces attentional resources required to read & decide whether letter string is a word. Psyco 350 Lec #13– Slide 39 Psyco 350

Semantic Networks & Priming N. R. Brown, U of Alberta Semantic Network general knowledge representation based on relatedness, meaning-based similarity Spreading Activation automatic consequence of processing a related information preparation for encountering the expected Activated concepts sometimes equated w/ consciousness & focal elements of WM (Cowan) Psyco 350 Lec #13– Slide 40 Psyco 350

Complex, stable knowledge structures Schemata & Scripts N. R. Brown, U of Alberta Schemata: Complex, stable knowledge structures occupations, geographical/architectural layouts, story structures, etc. Scripts: Schemata representing stereotypical event sequences Assumption – this knowledge is represented in semantic memory & used extensive in planning, comprehension, and recall (reconstruction) Psyco 350 Lec #13– Slide 41 Psyco 350

Bartlett 1st to recognize importance of schemata. N. R. Brown, U of Alberta Bartlett 1st to recognize importance of schemata. “War of the Ghosts” Study English undgrads read a North American Indian legend twice. Recalled the story once after 13 min and then over of the course of several month Psyco 350 Lec #13– Slide 42 Psyco 350

Bartlett – War of the Ghosts N. R. Brown, U of Alberta Main Findings: Reproduction distorted in ways that brought the story increasing in lines with European: narrative conventions beliefs re: physical & biological causality Interpretation: Participants combined fragmentary story memory with schematic knowledge to reconstruct a “sensible” story. Psyco 350 Lec #13– Slide 43 Psyco 350

Schemata: General Findings N. R. Brown, U of Alberta When present: Schema-consistent info, well remembered Schema-inconsistent info, less well remembered. When NOT present: Schema-consistent info often falsely remembered (schema-driven reconstruction) Schema-inconstant info generally not falsely remembered Psyco 350 Lec #13– Slide 44 Psyco 350

Recognizing Script-based Materials: Hannigan & Reinitz (2001) N. R. Brown, U of Alberta Schemata that capture general information about routine event sequences Eating in a restaurant, attending a movie, a visiting a doctor’s office, attending class, going to the beach Scripts identify central (& less central) actions & typical (& atypical) roles, & props. When not specified (or experienced) central actions & typical roles & props inferred/reconstructed Psyco 350 Lec #13– Slide 45 Psyco 350

Hannigan & Reinitz (2001): Method N. R. Brown, U of Alberta Materials: four 13-slide sequences a sequence represented one script-based activity (e.g. grocery shopping) including HIGH schema-relevant items (e.g. get shopping cart) LOW schema-relevant items (e.g., put food on belt) Presentation: 5.5 s/slide Psyco 350 Lec #13– Slide 46 Psyco 350

Hannigan & Reinitz (2001): Method N. R. Brown, U of Alberta Hannigan & Reinitz (2001): Method Psyco 350 Lec #13– Slide 47 Psyco 350

Hannigan & Reinitz (2001): Method N. R. Brown, U of Alberta Test Phase: 0-to-5 Recognition Confidence Judgment on each slide: 0 = certain slide not seen 5 = certain slide was seen Design: Item Type X Schema-relevance X Delay OLD high 13 min NEW low 48 hr Psyco 350 Lec #13– Slide 48 Psyco 350

Hannigan & Reinitz (2001): Results N. R. Brown, U of Alberta For OLD items: Reco very good high > low For NEW items @ 13 min delay: tendency to infer/reconstruct stronger for high-relevance items Psyco 350 Lec #13– Slide 49 Psyco 350

Hannigan & Reinitz (2001): Results N. R. Brown, U of Alberta Effect of Delay: OLD items: memory still very good False recognition  greatly for high-relevance items Psyco 350 Lec #13– Slide 50 Psyco 350

Semantic Memory: Main Points N. R. Brown, U of Alberta Semantic networks can represent simple facts and reflect conceptual similarity/relatedness Semantic priming is well established process serves to prime related information Schemata/scripts – complex, stable knowledge structures captures generalizations re: complex, but regular features of experience. facilitate/bias perception & memory Challenge: Develop detailed extensions of these notions to deal with full range of knowledge domains & modalities Psyco 350 Lec #13– Slide 51 Psyco 350