cogni finals

Knowledge representation

• What you use to recall these celebrities is more generally called——

• the form for what you know in your mind about things, ideas, events, and so on, in the outside world.

• declarative knowledge

• procedural knowledge

two kinds of knowledge structures

Declarative knowledge

• refers to facts that can be stated.

• Ex. the date of your birth, the name of your best friend, or the way a rabbit looks

Procedural knowledge

• refers to knowledge of procedures that can be implemented.

• Ex. are the steps involved in tying your shoelaces, adding a column of numbers, or driving a car.

standard laboratory experiments and neuropsychological studies.

There are two main sources of empirical data on knowledge representation:

experimental work

• In —-, researchers indirectly study knowledge representation because they cannot look into people’s minds directly.

• Instead, they observe how people handle various cognitive tasks that require the manipulation of mentally represented knowledge.

neuropsychological studies

In —, researchers typically use one of two methods:

1.  they observe how the normal brain responds to various cognitive tasks involving knowledge representation

2. they observe the links between various deficits in knowledge representation and associated pathologies in the brain.

1. pictorial, analogous image

2. highly symbolic, like words

3. pure abstract “mentalese” that is neither verbal nor pictorial

Different Kinds of Mental Representations

Symbolic representation

— meaning that the relationship between the word and what it represents is simply arbitrary.

pictures

• aptly capture concrete and spatial information in a manner analogous to whatever they represent.

• They convey all features simultaneously

Words

• on the contrary, handily capture abstract and categorical information in a manner that is symbolic of whatever the — represent.

• Representations in — usually convey information sequentially.

• They do so according to arbitrary rules that have little to do with what the—represent.

Mental imagery

is the mental representation of things that are not currently seen or sensed by the sense organs.

people with Down syndrome

• In the case of——, the use of mental images in conjunction with hearing a story improved memory for the material as compared with just hearing the story

Extreme view of imagery

all images of everything we ever sense may be stored as exact copies of physical images.

Dual-code theory

• - we use both pictorial and verbal codes for representing information in our minds.

• These two codes organize information into knowledge that can be acted on, stored somehow, and later retrieved for subsequent use; suggest that knowledge is represented both in images and in symbols

Paivio

According to —, mental images are analog codes

Analog codes

• — resemble the objects they are representing.

• For example, trees and rivers might be represented by —

Symbolic code

— is a form of knowledge representation that has been chosen arbitrarily to stand for something that does not perceptually resemble what is being represented

Symbol

— may be anything that is arbitrarily designated to stand for something other than itself

Propositional Theory

• suggests that we do not store mental representations in the form of images or mere words.

• We may experience our mental representations as images, but these images are epiphenomena

• According to this theory our mental representations more closely resemble the abstract form of a proposition

“mentalese”

mental representations sometimes called —

Epiphenomena

—secondary and derivative phenomena that occur as a result of other more basic cognitive processes

Proposition

— is the meaning underlying a particular relationship among concept

Predicate calculus

— to express the underlying meaning of a relationship. This method attempts to strip away the various superficial differences in the ways we describe the deeper meaning of a proposition

Propositional view

– both images and verbal statements are mentally represented in terms of their deep meaning, and not as specific images or words.

Ambiguous figures

-- it can be interpreted in more than one way; often are used in studies of perception

Propositional codes

-- are less likely to influence imaginal ones when participants create their own mental images, rather than when participants are presented with a picture to be represented; it may influence imaginal ones.

Implicit reference frame hint

Participants first were shown another ambiguous figure involving realignment of the reference frame

Explicit reference frame hint

Participants were asked to modify the reference frame by considering either “the back of the head of the animal they had already seen as the front of the head of some other animal” or “the front of the thing you were seeing as the back of something else”

Attentional hint.

Participants were directed to attend to regions of the figure where realignments or reconstruals were to occur.

Construals from “good” parts

Participants were asked to construe an image from parts determined to be “good” rather than from parts determined to be “bad”

Functional equivalence

—refers to individuals using about the same operations to serve about the same purposes for their respective domains

Functional equivalence hypothesis

• according to —although visual imagery is not identical to visual perception, it is functionally equivalent to it. This view essentially suggests that we use images rather than propositions in knowledge representation for concrete objects that can be pictured in the mind

• we represent and use visual imagery in a way that is functionally equivalent (strongly analogous) to that for physical percepts

Functionally equivalent things

— are strongly analogous to each other—they can accomplish the same goals.

Functionally equivalent images

— are thus analogous to the physical percepts they represent

schizophrenia

• Many people who suffer from— experience auditory hallucinations.

• These patients have difficulty discriminating between many different types of self-produced and externally provided stimuli.

Auditory hallucinations

• are experiences of “hearing” that occur in the absence of actual auditory stimuli.

• This “hearing” is the result of internally generated material.

• occur at least in part because of malfunctions of the auditory imaging system and problematic perception processes

Mental rotation

— involves rotationally transforming an object’s visual mental image.

Degraded stimuli

- are stimuli that are blurry, incomplete, or otherwise less informative—than for intact stimuli.

Practice effects

—improvements in performance associated with increased practice

primary motor cortex

In mental rotation, the — is activated when participants imagine manually rotating a stimulus

Stephen Kosslyn

• used a map of an imaginary island with various landmarks to determine whether mental scanning across the image of a map was functionally equivalent to perceptual scanning of a perceived map

• asked participants to imagine either a rabbit and a fly (to observe zooming in to “see” details) or a rabbit and an elephant (to observe whether zooming in may lead to apparent overflow of the image space).

representational neglect

• Patients suffering from spatial neglect - suffer from a related impairment called —

• a person asked to imagine a scene and then describe it ignores half of the imagined scene.

Spatial neglect

—, a person ignores half of his or her visual field

Patients suffering from representational neglect

When the patients had to recall the array, they could not describe the left portion

• propositions

• images

• mental models

An alternative synthesis of the literature suggests that mental representations may take any of three forms:

Mental models

• —- are knowledge structures that individuals construct to understand and explain their experiences

• provide an additional means of representation in addition to propositions and visual images.

• provide a way of explaining empirical findings, such as haptic and auditory forms of imagery, which seem quite different from visual images

Haptic imagery

suggests alternative modalities for mental imagery.

the left hemisphere

appears to be more proficient in representing and manipulating verbal and other symbol-based knowledge

right hemisphere

appears to represent and manipulate visuospatial knowledge in a manner similar to perception

1. visual imagery

2. spatial imagery

Two Kinds of Images

spatial imagery

— refers to images that represent spatial features such as depth dimensions, distances, and orientations

visual imagery

— refers to the use of images that represent visual characteristics such as colors and shapes

Case of L.H

who had a head injury at age 18. The injury resulted in lesions in the right and the left temporo-occipital regions, the right temporal lobe, and the right inferior frontal lobe.

Spatial cognition

— deals with the acquisition, organization, and use of knowledge about objects and actions in 2-D and 3-D space

Cognitive maps

• — are internal representations of our physical environment, particularly centering on spatial relationships ;

• offer internal representations that simulate particular spatial features of our external environment

Edward Tolman

• became one of the earliest cognitive theorists.

• He argued for the importance of the mental representations that give rise to behavior.

Hippocampus

— is involved in the formation of cognitive maps in humans

1. landmark knowledge

2. route-road knowledge

3. survey knowledge

Humans seem to use three types of knowledge when forming and using cognitive maps:

Landmark knowledge

— is information about particular features at a location and which may be based on both imaginal and propositional representations

Route-road knowledge

— involves specific pathways for moving from one location to another It may be based on both procedural knowledge and declarative knowledge

Survey knowledge

involves estimated distances between landmarks, much as they might appear on survey maps It may be represented imaginary or propositionally

rules of thumb

• When we use landmark, route-road, and survey knowledge, we sometimes use — that influence our estimations of distance.

• These — are cognitive strategies termed heuristics.

Right-angle bias

People tend to think of intersections as forming 90-degree angles more often than the intersections really do

Symmetry heuristic

People tend to think of shapes (e.g., states or countries) as being more symmetrical than they really are

Rotation heuristic

When representing figures and boundaries that are slightly slanted (i.e., oblique), people tend to distort the images as being either more vertical or more horizontal than they really are.

Alignment heuristic

People tend to represent landmarks and boundaries that are slightly out of alignment by distorting their mental images to be better aligned than they really are

Relative-position heuristic

The relative positions of particular landmarks and boundaries is distorted in mental images in ways that more accurately reflect people’s conceptual knowledge about the contexts in which the landmarks and boundaries are located, rather than reflecting the actual spatial configurations

Tversky

• — wondered whether propositional information might play a stronger role in mental operations when we think about settings in which we are participants, as compared with settings in which we are observers

• — noted that her research involved having the readers envision themselves in an imaginal setting as participants, not as observers, in the scene.

Converging operations

Concept

• - An idea about something that provides a means of understanding the world;

• the fundamental unit of symbolic knowledge, knowledge of correspondence between symbols and their meaning.

Category

• is a hierarchy of concepts; concept with members;

• a group of items into which different objects or particular concepts can be placed that belong together because they share some common features, or because they are all similar to a certain prototype.

natural categories and artifact categories

Categories can be subdivided in various ways. One commonly used distinction is between —

Natural categories

are groupings that occur naturally in the world, like birds or trees

Artifact categories

are groupings that are designed or invented by humans to serve particular purposes or functions, like automobiles and kitchen appliances

Ad hoc categories

• Not all categories are stable, however Some categories are created to achieve goals in everyday life or for a specific purpose, for example, “my best friends,” “things one can write on,” or “things I need to purchase in the supermarket.”

• These categories are —

• They typically are described not in words but rather in phrases. Their content varies, depending on the context

Basic level

• — sometimes termed a natural level of specificity

• , a level within a hierarchy that is preferred to other levels;

• the one that most people and to be maximally distinctive.

feature

• is an essential element of the concept.

• the features uniquely define the concept

Game

• Some concepts do not readily lend themselves to featural analysis.

• — is one such concept

• is a concept whose category members share features, but without any particular feature being common to all members

Prototype theory

— takes a different approach: grouping things together not by their defining features but rather by their similarity to an averaged model of the category.

Prototype

• is an abstract average of all the objects in the category we previously have encountered;

• encompasses the characteristic features that tend to be typical of an example (a bird can fly) but that are not necessary for being considered an example (an ostrich).

Characteristic features

• - describe the prototype but are not necessary for it;

• commonly are present in typical examples of concepts, but they are not always present

Classical concepts

• are categories that can be readily defined through defining features, such as bachelor;

• tend to be inventions that experts have devised for arbitrarily labeling a class that has associated defining features

fuzzy concepts

— are categories that cannot be so easily defined, such as game or death; tend to evolve naturally; their borders are, as their name implies

core

- refers to the defining features something must have to be considered an example of a category

Theory-based view

• A departure from feature-based, prototype-based, and exemplar-based views of meaning is a —of meaning,

• also sometimes called an explanation-based view

• A — of meaning holds that people understand and categorize concepts in terms of implicit theories, or general ideas they have regarding those concepts

Essentialism

- this view holds that certain categories, such as those of “lion” or “female,” have an underlying reality that cannot be observed directly

Piaget’s theory of cognitive development

According to that theory, children in the age range from roughly 8 to 11 years old are “concrete” thinkers. They cannot abstract features that are formal in nature

Semantic-network models

— suggest that knowledge is represented in our minds in the form of concepts that are connected with each other in a web-like form

Collins and Quillian’s Network Model

An older model still in use today is that knowledge is represented in terms of a hierarchical semantic network

hierarchical semantic

related to meaning as expressed in language—i.e., in linguistic symbols

Semantic network

— is a web of elements of meaning (nodes) in which the elements are connected with each other through links

Hierarchical model

• provides a high degree of cognitive economy.

• The system allows for maximally efficient capacity use with a minimum of redundancy

Inheritance

implies that lower level items inherit the properties of higher level items.

Semantic network

— has a hierarchical structure. The concepts (represented through the nodes; in color) are connected by means of relationships (arrows) like “is” or “has.”

Schema

— is a mental framework for organizing knowledge. It creates a meaningful structure of related concept

boundary extension

• When presented with a scene, people may extend the boundaries of that scene in their minds and remember details they had not actually seen.

• This is called

script

• contains information about the particular order in which things occur;

• are much less flexible than schemas;

• include default values for the actors, the props, the setting, and the sequence of events expected to occur.

Bower, Black, and Turner

—research suggested that scripts seem to guide what people recall and recognize—ultimately, what people know.

Jargon

—specialized vocabulary commonly used within a group, such as a profession or a trade.