Psy 211 Cognition SDSU exam 4

Mental Rotation Coglab: Why is it difficult to understand mental imagery using only introspection?

Peoples introspections widely vary

Mental Rotation Coglab: The mental rotation demonstration predicts that when comparing two shapes that are in fact the same, a participant's reaction time will have what type of relationship with the number of degrees the second shape is rotated from the first shape?

Exponential

Mental Rotation Coglab: If it takes you one second to mentally rotate an object thirty degrees how long will it take you to mentally rotate the object sixty degrees?

Answers: four seconds

Mental Rotation Coglab: A mental image could be useful for which of the following tasks?

Coming up with directions to your apartment.

Mental Rotation Coglab: While doing a mental rotation experiment like the one in the demonstration participants will often report ...

that they observe the two objects and eventually have a spontaneous insight into whether or not the two objects are the same.

concept

- an idea (ex: dog, freedom, space travel, walking)

- explicit memory consists of a set of concepts and links between them

- contains links to other concepts

- it also refers to a set of related "exemplars" (a fancy term for examples, also called instances)

- the instances of a concept form a category

Categories - the classical (definitional) view:

- the classical (definitional) view: a category is defined by a set of features that are "singly necessary and jointly sufficient" to constitute category membership (a group of related things in the world) (ex: Bachelor: unmarried, adult, male, human)

Categories - the prototype view:

- researchers have proposed that a category is defined by a small number of particularly good examples, which are called prototypes of the category.

- to determine whether or how well an item fits into a category, we determine how well it matches the prototypes

Categories - the instance-based (exemplar) view

- rather than abstracting and storing a single prototype, it is possible that people simply retain information about all of the individual exemplars

- to determine whether or how well an item fits into a category, we determine how well it matches the stored exemplars (instances) (a fancy term for examples)

Categories - the rule-based (theory-based) view

- when we have a rule (e.g., birds do not have fur), the rule may override the instances and prototypes (e.g., a bat cannot be a bird)

- rely on simple rules or criteria and do not require extensive approach

Which methods of categorization do we use?

What are different scenarios in which one might be better than another?

- prototype approach and exemplar approach

- Exemplar works better for small categories, and prototype works better for larger categories

What was done in the experiment done by Posner and Keele (1968)? What were the results of the experiment? What was done in the related Reed (1972) experiment?

- The experiment done by Posner and Keele showed that humans readily identify a prototype dot figure (a triangle) underlying a series of distorted patterns of dots (in Figure 17 to the left, numbers represent the level of distortion given in bits/dots). As a result, the more similar a novel pattern was to a category prototype, the easier it was to classify.

-Mike Posner and Steve Keele (1968) Instance Theory

Random sets of dots presented to subjects (4 categories)

Each category has 4 exemplars created relative to each category and each exemplar

Dots in exemplars create minor variations within each.

Subjects knew nothing of the dots previous to being tested, which eliminated biases from them.

Subjects were never shown the original prototype until tested as to which prototype fits into which category (predicated on their experience of the exemplars)

Test phase: original exemplars, new exemplars, and prototypes (originals)

Original Exemplars: 80% correct

New Exemplars: 50% correct

Prototypes: 68% correct

Average is created in mind of exemplars to compare to prototype

Subjects created mental representations of the average of each original exemplar (without seeing the original prototype) which increased recognition of prototypes (even if they've never been seen) with greater frequency than new exemplars.

What is family resemblance as it relates to categorization? How is it measured?

- Family resemblance: things in a category resemble each other in a number of ways

- led psychologists to propose that categorizations is based on how similar an object is to some standard representation of a category

- How it is measured: Rosch and Mervis asked subjects to list as many characteristics as they could about common objects. When an item's characteristics have a large amount of overlap with the characteristics of many other items in a category, the family resemblance is high, little overlap with other members of the category means family resemblance is low

→ strong relationship between family resemblance and prototypicality

What is the sentence verification technique?

- a technique in which the participant is asked to indicate whether a particular sentence is true or false

- subjects responded faster for objects that are high in prototypicality than objects with a low prototypicality → typicality effect

- Subjects presented with statements

- Yes if true, no if not true

- Measured how fast subjects responded if statement was true or false

- Prototypical category members are more affected by a priming stimulus

- Occurs when the presentation of one stimulus facilitates the response of another stimulus

- Name of a color used to prime a subject

- Subject presented with pairs of colors to be rated how close they were to the priming color "green"

- Pairs of colors most like the subjects personal prototype were reported being most "like their prototype."

What is priming? When does it occur?

- Priming is the implicit memory effect in which exposure to a stimulus influences response to a later stimulus.

- it occurs when the presentation of one stimulus(the priming stimulus) changes the way a person responds to another stimulus(test stimulus).

- Priming can occur following perceptual, semantic, or conceptual stimulus repetition

What is the semantic network model?

- Semantic Network model: Concepts are arranged in networks that represent the way concepts are organized in the mind

- Cognitive economy: shared properties are only stored at higher level nodes

What is spreading activation?

- Activation is the arousal level of a node

- When a node is activated, activity spreads out along all connected links

- Concepts that receive activation are primed and more easily accessed from memory

How did the Shepard (1967) study examining memory for pictures and memory for words work? What were the results of the study?

- Show individuals pictures and words

* tested by sampling 100 in recognition test

* which one did they see before

- visual memory for pictures was way better than memory for words

Shepard (1967): 612 pictures

Subjects saw each one for 6 seconds

Tested by sampling 100 of those images in a recognition test

100 pairs, say which of the two were studied

Which did you see before?

*did a same format study designed with words

Findings (Images): subjects were near 100% correct if tested immediately but dropped off sharply over a 4 month period to about 55% (from about 1 week).

Findings (words): about 100% correct immediately after but dropped to about 55% at 3 days post presentation.

Conclusion: Pictures persisted much longer than words in memory

What leads to good formation of visual memories?

- attention to details

- meaningfulness and relevance of details

- distinctive alternatives

What was Paivio's dual-code hypothesis? What predictions did it make?

- The dual coding theory proposed by Paivio attempts to give equal weight to verbal and nonverbal processing

- The theory assumes that there are two cognitive subsystems, one specialized for the representation and processing of nonverbal objects/events (i.e., imagery), and the other specialized for dealing with language

- Dual Coding theory identified three types of processing: (1) representational, the direct activation of verbal or nonverbal representations, (2) referential, the activation of the verbal system by the nonverbal system or vice-versa, and (3) associative processing, the activation of representations within the same verbal or nonverbal system

- Ss studies pairs of words, given one word and asked to recall paired word. Recall better for concrete word (house) rather than abstract noun (honor). Concrete words create images that other words can hang on to

EX,: given verbal code - "desk"

Given non verbal code - *picture of desk

when you see a picture you can form a code that is both verbal and non-verbal; can use both codes to simultaneously identify the object within it.

What did the Jonides and colleagues (1985) study demonstrate about conceptual knowledge?

- Reaction time of subjects tested when asked to identify points in a mental map, starting at a defined location.

- Points that were "further" away from the starting point had longer reaction times.

- Linear correlation between perceived distances and actual distances.

- Cognitive maps are pretty good at estimating distance, But heuristics can mislead knowledge

- familiar areas can be remembered as having much greater detail than less familiar areas, misleading the person recalling details that the familiar place is more vast.

What did mental scanning experiments find? (Kosslyn)

- when participants create mental images and then scan them in their minds

- what they found: Reaction time to identify details of drawing took longer when details were farther away from the focus of the boat they were asked to focus on (e.g. the flag)

How did Kosslyn interpret the results of his research on imagery?

- It takes longer to find parts, as distance from the start location increases

- Different parts of the image correspond to different locations in space, which is why it takes longer to scan farther in an image

- Ss imagine rabbit and elephant next to each other and rabbit and fly next to each other, asked if larger animal has whiskers- faster reaction time for larger animal. Imagery is similar to perception, images involve spatial representation

- Spatial Nature of Imagery. Island experiment- distance. Positive linear relationship between distance and reaction time. Visual imagery is spatial in nature

What is the pegword technique?

- a memory aid that involves linking words with numbers. It is utilized by creating mental associations between items to be remembered and items that are already associated with numbers. Involves imagery.

- Example is one-bun, two-shoe, three-tree, four-door

What are the similarities between IMAGERY and PERCEPTION? What are the differences?

Similarities: The mechanisms of perception and imagery overlap only partially

Differences:

- Perception occurs automatically, but imagery needs to be generated with effort

- perception is stable as one continues to observe, but imagery is unstable as it is lost w/o continued effort

- perceptual images are easier to recover than mental images

What did Behrmann and coworkers suggest about the double dissociation between perception and imagery?

- The mechanisms of perception and imagery overlap only partially, with the mechanism for perception being located at both lower and higher visual centers and the mechanism for imagery being located mainly in higher visual centers (Pg 289-290).

- Ex: Bottom up processing

How are neuropsychological findings related to imagery versus perception explained?

- Mental images are real. - They share many of the same properties as percepts, but also differ in important ways.

- Mental imagery relies on many of the same brain regions as perception. This overlap may explain why imagined events can have as powerful an emotional influence on people as perceived events.

- Neuropsychological evidence suggests that imagery of spatial information is supported by parietal structures, and imagery of objects and their visual properties is supported by temporal structures.

What were the results of the Ganis and coworker's fMRI study that measured brain activation for perception and imagery of objects?

- PET/fMRI studies show 70-90% of brain areas overlap between perception and imagery regions

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Where has it been proposed that the mechanism for imagery is located in the brain? Where has it been proposed that the mechanism for perception is located in the brain?

- Mechanism for imagery and perception overlap partially.

Mechanism for imagery is located mainly in higher visual center. Imagery involves top-down processing.

Mechanism for perception is located at both lower and higher visual centers. Perception involves bottom-up processing.

What are imagery neurons? What do they respond to?

- Imagery neurons: Neurons that not only fire for a physical stimulus, but a mental image of it too. In other words, these neurons respond to both perceiving an object and to imagining it

What is an epiphenomenon?

- something that accompanies the real mechanism but is not actually part of the mechanism. Mental images indicate that something is happening in the mind but don't tell us how it is happening