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Percept al Learning &Perceptual Learning & MemoryLearning & MemoryArlo Clark-Foos, Ph.D.

• Perceptual Skill Learningability to detect and classify particular sensory stimuli

Definitions

Detecting hanging Chads

• Perceptual Memoryunconscious encoding of specific stimuli and unconscious changes in performance of tasks involving those stimuli

• Discrimination between stimuli

• Improvement

Becoming Experts

• Music/Language• Food/Beer• Your expertise• Much more!

Facilitates processing• Learning to detect stimuli• Distinguishing between similar stimuli

Perceptual L & M

Distinguishing between similar stimuli

Does NOT change response to stimulus!• Non-associative (c.f., habituation)

Becoming Experts“Saison Dupont puts itself firmly in the funky category. The nose is like cut grass, and definitely has that funk. Good amount of aroma hops, clean snappy finish. Lingering bitterness and a bit of the musty funk I’ve come to know as Brett Lotsfunk I ve come to know as Brett. Lots of lemons here, but like lemon-grass and not the fruit itself. My initial impression uncorking the bottle was exactly like a freshly cut lawn in the rain, but in a good way.”

Take Home Message: “It is yummy”* Perceptual L&M changes your processing and identification, not your response to stimuli.

1. Attentional Weighting• focus

2. Feature Imprinting• template

Mechanisms of Perceptual Skill Learning(Goldstone, 1998)

template3. Differentiation

• categories4. Unitization

• holistic

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1. Attentional Weighting2. Feature Imprinting3. Differentiation4 Unitization

Mechanisms of Perceptual Skill Learning(Goldstone, 1998)

4. Unitization

Male Greebles

Female Greebles

Male or Female?

Perceptual Skill Learning: Identifying Stimuli

Deemphasize formerly salient features and emphasize features that reliably predict new categories

Categorical Perception“One of these things is not like the others”

Categorical Perception

Category Boundaries

Speech PerceptionIdentifying speech sounds • Eimas & Corbitt (1973)

• Presented range of computer-generated phonemes, /da/ or /ta/, and asked Ps to identify which

Speech Perception(Eimas & Corbit, 1973)

We perceive in categories!

phoneme they heard

• McGurk Effect (McGurk & MacDonald, 1976)

• Foreign Language (ü or ß)

Are perceptual categories learned or innate?

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Categorizing Faces (Beale & Keil, 1995)

Sharpness of categorization judgment is a function of familiarity

• Detecting the undetectable

• Hyperacuity

Stimulus Detection

• Vernier Acuity

There are limits!

• Which of these chicks is (fe)male?Are you a chick expert?

• Experts can do this 98% of the time at 1,000 chicks/hour!• Once the critical feature was identified (shape

of the cloacal), anyone could do it.

• Judging parallel lines to 45 degree ref. (Shiltz et al., 1999)

• 10-30% improvement over 1000s of trials

Neurological Basis

• Early stages of sensory processing

1. Specificity of learning2. Role of attention

• If told to ignore, you will not learn3 Speed of learning

Properties of Perceptual Skill Learning (Karni, 1996)

3. Speed of learning• It takes time to make a change

4. Role of sleep

Remember: Most sensory cortices have topographic representations

1 Determine “tuned” frequency for cells in

What happens in the brain?

1. Determine tuned frequency for cells in auditory cortex

2. Associate non-tuned frequency with foot shock over multiple trials.

3. Observe changes in optimal (i.e., tuned) frequency for cells in auditory cortex.

(Weinberger et al., 1993)

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More Guinea Pigs

Shifting the topographic map

How about monkeys?

• Amnesics and vernier acuity• Cohen & Squire (1980)

Can it be unconscious? Distinct Representations

Perceptual Memory

• Very specific

• Dèjá vu• Did this already happen?

Perceptual Memories

Did this already happen?• Familiarity without

recollection

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facilitation of processing of specific materials to which we have been recently exposed

• Word Stem Completion

Repetition Priming

MOT____

• Lexical Decision Task (LDT)WORD/NONWORD Judgment

1. COLD2. hot-COLD3. hot-?

Generation and Fan Effects(Jacoby, 1983)

Generation Effect Fan Effect

Statistically independent/unrelated (Tulving et al., 1982).• Recognition of 96 words drops steeply from a 1 to a 7

day test but priming (word completion) is unchanged

Different brain structures (Perceptual ≠ Cognitive Memory)

• H M and the Gollins partial pictures task

Other Distinctions Between Recognition (Explicit) and Priming

• H.M. and the Gollins partial pictures task

• Perceptual Priming• repetition-produced facilitation of processing

for the sensory qualities of a stimulus.• Associative Priming

More on Priming

• facilitation of item processing following a single exposure to a combination of information.

• Conceptual Priming• priming of entire categories of words

• Associative Priming• Both amnesics and controls improve on Stroop

More on Priming• Probably early in processing

• Alzheimer’s: Perceptual Conceptual

Hyperspecificity of Repetition Priming

p• Occipital Damage: Perceptual

Conceptual

• Less activation in posterior cortex for repeated words/objects presented visually (Schacter & Buckner, 1998)

(Gabrielli et al., 1995)

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• Perceptual Learning ≠ Perceptual Memory

• Categorical Perception & Stimulus Detection

Summary

Detection

• Perceptual Priming