PSY 368 Human Memory Recognition cont Experiment 2

PSY 368 Human Memory Recognition cont.

Experiment 2 • Signal Detection (Download details from BB) • Like last time, find 3 participants • You’ll need index cards for the words (write one word per card) • Read instructions to participants, the IV is manipulated with different instructions for each condition, so make sure that you read the correct instructions. You’ll need to print out 3 copies of the “memory test” (1 for each participant) • Fill out the datasheet and bring it to class on Monday (March 5 th, date in assignment is old Fall date). I will compile data for whole class and bring it on Wednesday March 7 th • Reports will be due the Wednesday after Spring Break (March 21 st),

Experiment 1 results • Overall (N = 18) • General report comments • Immediate 7. 6 items • Delayed 6. 0 • Distraction 3. 5 • Don’t identify your participants • Stick to APA style as much as you can • Include your datasheet Primacy effect in Recency effect all three conditions strongest in immediate condition

How does Recognition work? • Two classes of theories • Single process theories - retrieval is one process regardless of task • Tagging Model (Yntema & Trask, 1963) • Strength Theory (Wickelgren & Norman, 1966) • Dual process theories - two processes needed for retrieval - can be task dependent • Generate-recognize model (G-R) • e. g. , Anderson & Bower (1972)’s HAM • Remember/Know processes model (R/K)

Dual-process theories Generate-recognize model (G-R) • Recall is made up of two processes • First, generate a set of plausible candidates for recall (Generation stage) • Second, confirm whether each word is worthy of being recalled (Recognition stage – not the same as the recognition test) • Recognition is made up of only one process • Because the experimenter provides a candidate, recognition does not need the generation stage

Dual-process theories Remember versus Know Process Model (Tulving, 1985; Gardiner, 1988) Relatively recent change in recognition methodology When you recognize something, do you: Specifically remember (linked to Episodic memory) Conscious recollection of the information’s occurrence at study Just somehow know (linked to Semantic memory) Knowing that it was on the list, but not having the conscious recollection, just a “feeling of knowing”

Dual-process theories Remember versus Know Process Model Tulving (1985) Present subjects with 27 category-member pairs (FRUIT– pear) Prob(remember Recall tests: ) Free recall test 0. 88 Cued recall test (category) FRUIT 0. 75 Cued recall test (category + first letter of target) FRUIT- p 0. 48 Results The proportion of remember judgments decreased over the three kinds of tests

Dual-process theories Remember versus Know Process Model Gardiner et al (1990, 1991, 1993) • Remember/Know processes • Make R/K judgment for “Old” items • Remember = consciously recollect details of the item’s presentation • Know = sure an item was presented, but can’t recall any of the details of presentation • R/K differ by: Picture superiority effect • R: P > W • K: W > P Word frequency effect • R: L > H • K: H = L Generation effect • R: G > R • K: R = G

Remember Versus Know Remember versus Know Process Model Gardiner et al (1990, 1991, 1993) gives an explanation: Remember judgments are influenced by conceptual and attentional factors Know judgments are based on a procedural memory system This is similar to a distinction between explicit and implicit memory (more on this next week)

Techniques used to distinguish dual processes • Signal Detection Theory • A technique for separating discrimination (“true” detection) from response bias • Process Dissociation (next week) • A technique for separating intentional (effortful) retrieval processes from incidental (automatic) retrieval processes • May want to go back and review pages 111 -114

Signal Detection Theory • A model for explaining recognition memory • Based on auditory perception experiments: • Typical Task: • Ask participants to detect a faint tone (signal) presented against a background of noise • The tone’s loudness against the background noise is manipulated Volume • Signal Detection Theory: Background Noise Hard-to-Detect Signal Easy-to-Detect Signal

Signal Detection Theory • Brief History • In World War II radar waves were used to detect enemy aircraft. • The soldiers had to determine if the little spots of light are enemies, or simple noise (I. e. birds). • There was no clearly defined criteria for making these kinds of decisions. SIGNAL: Are the spots on the screen enemies? yes no • Consequences: • If an enemy went undetected, people could be killed. • If noise was interpreted as an enemy, time and money would be lost and people would be put in harm’s way DECISION: Should you scramble the jets? yes Hit False alarm no Miss Correct reject

Signal Detection Theory • Response bias is based on a participant’s preference for a particular outcome. • Preferences are based on costs & rewards • For example, • People will die because I failed to detect enemy, that is a very high cost. • If congress yells at me for spending money, that is not a very high cost. SIGNAL: Are the spots on the screen enemies? yes no DECISION: Should you scramble the jets? yes Hit False alarm no Miss Correct reject

Signal Detection Theory • Criterion level (C or β) is set based on outcome preferences. • Criterion level: The intensity at which a signal will be reported as being present (Not the intensity at which it is SIGNAL: Are the spots perceived). • High Criterion: less hits but also less false alarms • Low criterion: more hits but also more false alarms on the screen enemies? yes no DECISION: Should you scramble the jets? yes Hit False alarm no Miss Correct reject

Signal Detection Theory • Criterion level (C or β) is set based on outcome preferences. • Criterion level: The intensity at which a signal will be reported as being present (Not the intensity at which it is No - Criterion + Call for perceived). alert jets probability • High Criterion: less hits but also less false alarms • Low criterion: more hits but also more false alarms Signal (enemy) Noise stimulus intensity

Signal Detection Theory • d’ (“Dee-prime”) = Discriminability Low d’ • If d’ is low, then this means there is low discriminability. • The noise and stimulus are highly overlapping. • d’ = 0: pure chance probability • The difference between the means Signal (enemy) Noise stimulus intensity • If d’ is high, then this means there is high discriminability. • d’ = 1: moderate performance • d’ = 4. 65: “optimal” (corresponds to hit rate=0. 99, false alarm rate=0. 01) probability high d’ Signal (enemy) Noise stimulus intensity

Signal Detection Theory • Recognition accuracy depends on: • Whether a signal (noise/target memory) was actually presented • The participant’s response INCORRECT • Thus, there are four possible outcomes: • Hits • Correctly reporting the presence of the signal • Correct Rejections • Correctly reporting the absence of the signal • False Alarms • Incorrectly reporting presence of the signal when it did not occur • Misses • Failing to report the presence of the signal when it occurred

Signal Detection Theory • Assumptions: • Memory traces have strength values (i. e. activation levels) • Activation levels dictate how “familiar” a stimulus feels • Traces vary in terms of their familiarity, based on: • Attention paid to the stimulus during encoding • The number of repetitions • Familiarity values for “old” and “new” items are each normally distributed • On average, “new” items are less familiar than “old” items • However, some distractors are quite familiar because they appear often in other contexts or are similar to “old” items • Thus, there can be overlap between the distributions • Items that surpass a threshold (i. e. response criterion) of familiarity are judged “old” 18

Signal Detection Theory • Everything more familiar than (to the right of) the response criterion (beta or β) will be judged “old” • • Correct rejections (in green) • A centrally placed β is unbiased • Everything less familiar (i. e. to the left of β) will be judged “new. ” • Hits (in green) • Misses (in red) Above, the same distribution with the focus on the lure distribution to highlight: • False alarms (in red) • D prime (d’) represents: • The distance between the distributions • The participant’s ability to discriminate the 19 two distributions

Signal Detection Theory • A more liberal guesser will: • Have a response criterion shifted to the left • Accept more targets as “old” (i. e. hits) • Accept more lures as “old” (i. e. false alarms) • A more conservative guesser will: • Shift β to the right • Have fewer hits • Have fewer false alarms • Thus, the overlap in the distribution leads to: 20 • Trade offs between hits and false alarms • Depends on the placement of the response criterion

Signal Detection Theory • Calculating d’ and C (or β) • Discriminability (d’): • Step 1) Look up the z-score for the average Hit and False Alarm rates. • Step 2) Apply the formula d’ = z. HIT – z. FA, where z. FA is the z-score for FAs and z. HIT is the z-score for Hits. • Criteria C (or β): • Take the negative of the average of z. HIT and z. FA. This is the criterion value C. • Remember that positive C values indicate a conservative response bias, while negative C values indicate a liberal response bias. • We will go over this in class again next week when we have our data for Experiment 2 http: //memory. psych. mun. ca/models/dprime/ 21

Face Recognition • Special recognition ability

Face Recognition • Evidence for special ability: (1) Prosopagnosia • The inability to recognize previously seen faces, with relative sparing of other perceptual, cognitive and memory functions. • Intact ability to identify people using nonfacial features (voice) • Due to brain injury (typically to the right temporal lobe) • Broad Subtypes: 1. Apperceptive - failure to generate a sufficiently accurate percept to allow a successful match to stores of previously seen faces. 2. Associative - accurate percept, but failure to match because of loss of facial memory stores or disconnection from them.

Face Recognition • Evidence for special ability: (2) Newborn preferences • Studies done by Fantz (1961, 1963) - had kids look at three kinds of figures • Morton and Johnson (1991) report that new-born babies will preferentially view faces

Face Recognition • Evidence for special ability: (3) Face inversion effect • Yin (1969) found that whilst people are generally better at recognising upright faces than they are other objects. They are worse for inverted faces than they are for other inverted objects. • This suggests that the processing underlying normal face recognition is different from those underlying object recognition.

The ‘Thatcher Illusion’ (Thomson, 1980) 26

The ‘Thatcher Illusion’ (Thomson, 1980) 27

Why does the ‘Thatcher illusion’ occur? • Bartlett and Searcy (1993) conducted experiments to measure face ‘grotesqueness’. • Their results supported the “configural processing hypothesis” • i. e. We have a difficulty in understanding the configuration of features when faces are inverted. • We aren’t aware of the odd configuration of elements within the inverted Thatcher image. 28

Face Recognition • Evidence for special ability: (4) Pop-out effect for faces (Herschler & Hochstein, 2005) Find the human face in the display as fast as you can. Ready?

Face Recognition Find the human face in the display as fast as you can. Ready?

Face Recognition • Evidence for special ability: (4) Pop-out effect for faces (Herschler & Hochstein, 2005) Now find the animal face. Ready?

Face Recognition

Summary (1) Recognition is an explicit memory test. (2) Single- and dual-process theories of recognition (3) Single-process can’t account for differences across recall and recognition (4) G-R theory can’t account for items that are recalled, but not recognized (5) Face recognition seems to be a special ability

The Mirror Effect • Observed when “The type of stimulus that is accurately recognized as old when old is also accurately recognized as new when new. The type that is poorly recognized as old when old is also poorly recognized as new when new. ” (Glanzer & Adams, 1985, p. 8) • Pervasive in recognition tests • High/low word frequency and hit/false alarm rates, presentation rate, age of subject, . . .

The Mirror Effect - Example The Mirror Effect and the Word Frequency Effect Word Frequency High Low Hits 27. 84 31. 00 False Alarms 10. 20 7. 63 Source: Human Memory, p. 214

The Mirror Effect • Significance: It eliminates all theories of recognition based on a unidimensional conception of strength or familiarity (single process models) • May be able to be explained by dual process models • Explanations for the mirror effect are still being formed

Dual-process theories Dissociating Recollection and Familiarity • Process Dissociation Procedure (Jacoby, 1991) • Task: • Participants study two sets of items in different contexts • Two different recognition tests follow: • Inclusion Condition: • Say “yes” if they recognize an item from either context • Correct recognition = Recollection + Familiarity • Exclusion Condition: • Say “yes” only if they recognize an item from one of the two contexts • Familiarity = False alarms in exclusion condition • Recollection = Inclusion’s correct recognition minus Familiarity