Fundamental to all human cognition is the representation of knowledge. A great portion of cognitive psychology deals with how knowledge is represented in the mind. The essential issue of representational knowledge is how ideas, events and things are stored and schematized in the mind. Knowledge can be represented both in the forms of episodic and semantic forms.
In the present lesson we inquire into more complex aspects of knowledge. We investigate into more complex type of representation called prepositional representation. We shall see that propositions are remarkably versatile devices for representing Information. Some theorists argue that our knowledge is represented in two different ways. In particular they contend that our verbal knowledge is represented by propositions. Whereas our visual knowledge, the knowledge we use to construct images and to perceive scenes is not. Further some theorists have proposed that the human brain contains two separate processing systems. One specialized for processing language and the other specialized for processing spatial, non-prepositional representations. We will also examine visual imagery and the evidence concerning brain processes with an eye toward determining whether all of our knowledge is propositional.
REPRESENTATION OF KNOWLEDGE
Knowledge representation comprises the various ways in which our minds create and modify mental structures that stand for what we know about the world outside cf our minds
Representation of knowledge deals with how information derived from sensory experiences, is symbolized and combined with the things stored in the brain. One of the problem we have in communicating with each other is that the world is never identically represented. What one see, hear, smell, taste or feel is not the same as what others experience and represent in memory; In spite of these inherent dissimilarities between representations of knowledge~ most humans do experience and depict experiences in similar enough ways to get along well in the world. In this lesson we especially deal with internal representations of knowledge.
EPISODIC AND SEMANTIC KNOWLEDGE
Our cognitive activities are based upon both episodic and semantic knowledge. Episodic knowledge is autobiographical and includes memories of events and episodes that occurred at a particular time and place. For example, the memory of what was served at dinner last night is episodic in nature.
Semantic or world knowledge include factual, conceptual and linguistic information that is not tied to a particular context. Semantic knowledge includes, among other things, the definition of words and our knowledge of concepts such as animal and gravity.
The distinction between episodic and semantic information has stimulated research into everyday activities of reading, thinking and using conceptual knowledge to solve problems, yet the distinction is not a sharp one. Our world knowledge is based on and evolves out of our knowledge of episodes, and there is no discrete-"point at which -. ' information loses its ties with contextual information. Episodic and semantic knowledge differ mainly in the degree to which they include contextual information.
Some relatively simple model of semantic memory have been put forth to explain how people made simple inferences and verify sentences. Hierarchical network model spreading activation model and feature comparison models explain how the semantic knowledge is represented.
Many theorists believe that the simple models of semantic memory are too narrow in scope and too closely tied to the sentence verification paradigm. These theorists have devised broad, global models of cognition that are expressed in the form of a computer program and are designed to comprehend complex utterances, remember prose and so on.
In the present lesson we deal with more complex models of knowledge such as prepositional knowledge, human associative memory, spatial knowledge and imagery etc.,
PROPOSITIONAL KNOWLEDGE
A proposition is a symbolic representation that expresses a relationship between two or more concepts and that can be either true or false for example, "Sandeep is tall" is a proposition, where as just the words "tall" or "is tall" are not proposition. A proposition is an assertion that may be understood and evaluated. It is an abstract representation of the meaning conveyed by language, by all words, phrases, sentences, paragraphs, and whole speeches and documents.
One way to show that elements of a proposition are in a list format. The list begins with a relation followed by a set of arguments. For example, in the sentence "The car hit the truck", the proposition HIT (CAR, TRUCK) represents the meaning of the sentence and this sentence includes the concepts HIT, CAR and TRUCK. HIT is called the relational term of the proposition because it designates the relationship between CAR and TRUCK. By convention, the relational term is written as the first term of the proposition and is placed outside the parentheses, which enclose the two concepts (called arguments) that are related by the relational term. This type of layout is called a propositional format. One more example of propositional format is "the girl ate the salad" can be represented as EAT (GIRL, SALAD)
Propositions are capable of embodying the complex knowledge that is used to comprehend prose, carry on conversations, form images, and so on.
The propositional representation of knowledge is too simple to enable us to perform many everyday tasks.
In this section, We examine the evidence that people represent complex information in a prepositional format. Then we inquire into a global model of processing that uses propositional representations. We shall see that many investigators believe that prepositional representations can embody most if not all of our semantic and world knowledge.
Propositions And Paragraph Processing
It has been proved in several studies that people use propositional representations in processing sentences and stories.
Observations suggested that in reading paragraphs, the subjects had represented the meaning of the passage in a prepositional form.
Some theorists are now constructing large-scale or global models of comprehension and memory using the proposition as a basic unit of knowledge the nature of global models can be illustrated by examining HAM, one of the first and most influential of the global models.
Human Associative Memory (Ham)
Human associative memory model was constructed by Anderson and Bower. This model aims to specify the knowledge that people use in performing tasks ranging from reading to remembering to forming images. Unlike the simple models of semantic memory, the global models are concerned with the knowledge that underlies all of our cognitive activities, even the most complex ones. HAM model also aims to specify the mechanisms whereby people use their knowledge to perform everyday activities.
In the present lesson we inquire into more complex aspects of knowledge. We investigate into more complex type of representation called prepositional representation. We shall see that propositions are remarkably versatile devices for representing Information. Some theorists argue that our knowledge is represented in two different ways. In particular they contend that our verbal knowledge is represented by propositions. Whereas our visual knowledge, the knowledge we use to construct images and to perceive scenes is not. Further some theorists have proposed that the human brain contains two separate processing systems. One specialized for processing language and the other specialized for processing spatial, non-prepositional representations. We will also examine visual imagery and the evidence concerning brain processes with an eye toward determining whether all of our knowledge is propositional.
REPRESENTATION OF KNOWLEDGE
Knowledge representation comprises the various ways in which our minds create and modify mental structures that stand for what we know about the world outside cf our minds
Representation of knowledge deals with how information derived from sensory experiences, is symbolized and combined with the things stored in the brain. One of the problem we have in communicating with each other is that the world is never identically represented. What one see, hear, smell, taste or feel is not the same as what others experience and represent in memory; In spite of these inherent dissimilarities between representations of knowledge~ most humans do experience and depict experiences in similar enough ways to get along well in the world. In this lesson we especially deal with internal representations of knowledge.
EPISODIC AND SEMANTIC KNOWLEDGE
Our cognitive activities are based upon both episodic and semantic knowledge. Episodic knowledge is autobiographical and includes memories of events and episodes that occurred at a particular time and place. For example, the memory of what was served at dinner last night is episodic in nature.
Semantic or world knowledge include factual, conceptual and linguistic information that is not tied to a particular context. Semantic knowledge includes, among other things, the definition of words and our knowledge of concepts such as animal and gravity.
The distinction between episodic and semantic information has stimulated research into everyday activities of reading, thinking and using conceptual knowledge to solve problems, yet the distinction is not a sharp one. Our world knowledge is based on and evolves out of our knowledge of episodes, and there is no discrete-"point at which -. ' information loses its ties with contextual information. Episodic and semantic knowledge differ mainly in the degree to which they include contextual information.
Some relatively simple model of semantic memory have been put forth to explain how people made simple inferences and verify sentences. Hierarchical network model spreading activation model and feature comparison models explain how the semantic knowledge is represented.
Many theorists believe that the simple models of semantic memory are too narrow in scope and too closely tied to the sentence verification paradigm. These theorists have devised broad, global models of cognition that are expressed in the form of a computer program and are designed to comprehend complex utterances, remember prose and so on.
In the present lesson we deal with more complex models of knowledge such as prepositional knowledge, human associative memory, spatial knowledge and imagery etc.,
PROPOSITIONAL KNOWLEDGE
A proposition is a symbolic representation that expresses a relationship between two or more concepts and that can be either true or false for example, "Sandeep is tall" is a proposition, where as just the words "tall" or "is tall" are not proposition. A proposition is an assertion that may be understood and evaluated. It is an abstract representation of the meaning conveyed by language, by all words, phrases, sentences, paragraphs, and whole speeches and documents.
One way to show that elements of a proposition are in a list format. The list begins with a relation followed by a set of arguments. For example, in the sentence "The car hit the truck", the proposition HIT (CAR, TRUCK) represents the meaning of the sentence and this sentence includes the concepts HIT, CAR and TRUCK. HIT is called the relational term of the proposition because it designates the relationship between CAR and TRUCK. By convention, the relational term is written as the first term of the proposition and is placed outside the parentheses, which enclose the two concepts (called arguments) that are related by the relational term. This type of layout is called a propositional format. One more example of propositional format is "the girl ate the salad" can be represented as EAT (GIRL, SALAD)
Propositions are capable of embodying the complex knowledge that is used to comprehend prose, carry on conversations, form images, and so on.
The propositional representation of knowledge is too simple to enable us to perform many everyday tasks.
In this section, We examine the evidence that people represent complex information in a prepositional format. Then we inquire into a global model of processing that uses propositional representations. We shall see that many investigators believe that prepositional representations can embody most if not all of our semantic and world knowledge.
Propositions And Paragraph Processing
It has been proved in several studies that people use propositional representations in processing sentences and stories.
Observations suggested that in reading paragraphs, the subjects had represented the meaning of the passage in a prepositional form.
Some theorists are now constructing large-scale or global models of comprehension and memory using the proposition as a basic unit of knowledge the nature of global models can be illustrated by examining HAM, one of the first and most influential of the global models.
Human Associative Memory (Ham)
Human associative memory model was constructed by Anderson and Bower. This model aims to specify the knowledge that people use in performing tasks ranging from reading to remembering to forming images. Unlike the simple models of semantic memory, the global models are concerned with the knowledge that underlies all of our cognitive activities, even the most complex ones. HAM model also aims to specify the mechanisms whereby people use their knowledge to perform everyday activities.
The prepositional structure of the sentence 'At home, Venu read Gitanjali'.
The first association consists of a context and a fact. The fact indicates what happened and the context indicates the time and the place of the event.
The second association is between a location and time.
The third association consists of a subject and a predicate. The subject indicates the topic of the fact, and the predicate indicates a property of the subject or tells what happened to the subject.
The fourth association consists of a relation and an object.
The fifth association is between a concept and an instance of that concept.
These five associations combine to form a treelike structure.