Knowledge Representation Knowledge Representation and Retrievaland Retrieval
PSY 421 – Fall, 2004PSY 421 – Fall, 2004
OverviewOverview
How is information organized in How is information organized in memory?memory?
Retrieving information – propositional Retrieving information – propositional networksnetworks
Retrieving everyday information Retrieving everyday information Tip of the Tongue PhenomenonTip of the Tongue Phenomenon
What we have discussed about What we have discussed about memory…memory…
Structure of MemoryStructure of Memory• SM -> STM -> LTMSM -> STM -> LTM• Working MemoryWorking Memory• No distinctionsNo distinctions
Memory ProcessesMemory Processes• EncodingEncoding• RetrievalRetrieval• Match between encoding and retrievalMatch between encoding and retrieval• ForgettingForgetting• Evidence for memory distortionsEvidence for memory distortions
Knowledge Representation in MemoryKnowledge Representation in Memory• How can I get the once bit of information out of How can I get the once bit of information out of
memory that I need?memory that I need?
How is information represented in memory?How is information represented in memory? Episodic vs. semantic memoryEpisodic vs. semantic memory
• Who taught you how to draw a map?Who taught you how to draw a map?• Who taught you how to use the internet?Who taught you how to use the internet?• Who taught you how to tie your shoes?Who taught you how to tie your shoes?• Who taught you the words to “Take me out to the Who taught you the words to “Take me out to the
ballgame”?ballgame”?• When did you learn how to divide using fractions?When did you learn how to divide using fractions?
Models of representing and retrieving Models of representing and retrieving categorical knowledgecategorical knowledge• Hierarchical Network ModelHierarchical Network Model• Feature Comparison ModelFeature Comparison Model• Spreading Activation ModelSpreading Activation Model
Common Aspects of these ModelsCommon Aspects of these Models Category verification taskCategory verification task
Feature verification taskFeature verification task
Metaphors for how information is Metaphors for how information is representedrepresented
Spreading activation – activation of Spreading activation – activation of one node spreads to other related one node spreads to other related nodesnodes
Primary measure of performance is Primary measure of performance is speed, not accuracyspeed, not accuracy
Network ModelsNetwork Models
Associative Associative network with network with concepts concepts represented as represented as nodesnodes
Nodes can be Nodes can be “close by”“close by”
Try NOT to think of Try NOT to think of this as a neural this as a neural model where the model where the nodes are neuronsnodes are neurons
hops
meowsLongtail
Pointed ears
Climbstrees
cat
Hierarchical Network ModelHierarchical Network Model Collins and Quillian (1969; 1970)Collins and Quillian (1969; 1970) Specific nodes are nested deeper within the Specific nodes are nested deeper within the
modelmodel Concept nodes and feature nodesConcept nodes and feature nodes Higher in the hierarchy, the faster you are to Higher in the hierarchy, the faster you are to
access that informationaccess that information Problems with the model are numerousProblems with the model are numerous
Cat
Physical features sounds movement
Long tailPointed
earspurrs meows jumps hops
Feature Comparison ModelFeature Comparison Model Smith, Shoben, and Rips (1974)Smith, Shoben, and Rips (1974) Knowledge consists of a set of Knowledge consists of a set of
descriptions of featuresdescriptions of features• Defining features = those that are Defining features = those that are
essential for the meaning of the conceptessential for the meaning of the concept• Characteristic features = those that are Characteristic features = those that are
not essential; perhaps accidentalnot essential; perhaps accidental ProblemsProblems
Spreading Activation ModelSpreading Activation Model
Collins and Loftus (1975)Collins and Loftus (1975) Concept nodes are organized in an Concept nodes are organized in an
associative networkassociative network• Associations are not hierarchicalAssociations are not hierarchical• Activations vary on strengthActivations vary on strength
EvidenceEvidence• Semantic primingSemantic priming
Propositional NetworksPropositional Networks Proposition = smallest unit of Proposition = smallest unit of
knowledge that can stand alone and knowledge that can stand alone and be declared true or falsebe declared true or false
Abstract representations underlying Abstract representations underlying what we think and say (McNamara, what we think and say (McNamara, 1994)1994)
Networks are constructed from facts Networks are constructed from facts and relationships we learn and and relationships we learn and experienceexperience
Foundation for the study of languageFoundation for the study of language
Evidence for Propositional Evidence for Propositional NetworksNetworks
Mediated priming = amount of priming of Mediated priming = amount of priming of one node to another depends on degree of one node to another depends on degree of separation within the network (measure = separation within the network (measure = speed)speed)
Fan Effect = as more and more facts are Fan Effect = as more and more facts are learned about a concept, the ability to learned about a concept, the ability to quickly and easily retrieve any one of the quickly and easily retrieve any one of the facts decreases (response competition/ facts decreases (response competition/ interference)interference)
Everyday KnowledgeEveryday Knowledge Foreign Language Knowledge – long term Foreign Language Knowledge – long term
retention is dependent on initial learningretention is dependent on initial learning Permastore – permanent memory for Permastore – permanent memory for
information that is overlearnedinformation that is overlearned Math – if math is learned over a long Math – if math is learned over a long
period of time (many years in school) it is period of time (many years in school) it is retained longer than if learned quicklyretained longer than if learned quickly
Cognitive Psychology – some forgetting Cognitive Psychology – some forgetting but some facts remembered long term but some facts remembered long term (Research Methods, however, was retained (Research Methods, however, was retained for a long time)for a long time)
Applications for EducationApplications for Education
More everyday knowledgeMore everyday knowledge
People’s NamesPeople’s Names• Interaction of face recognition, Interaction of face recognition,
biographical information, and namesbiographical information, and names SongsSongs
• Repetition within the songRepetition within the song• Sharing words with the titleSharing words with the title• Occurrence early in the songOccurrence early in the song• Association with melody is importantAssociation with melody is important
Tip of the Tongue PhenomenonTip of the Tongue Phenomenon
We know we know some piece of We know we know some piece of information but when asked, we information but when asked, we cannot come up with itcannot come up with it
Available but not accessibleAvailable but not accessible How often – a few times a week?How often – a few times a week? Alternatives are not randomAlternatives are not random More alternatives will actually More alternatives will actually
interference with retrieving the right interference with retrieving the right one (especially phonologically similar one (especially phonologically similar alternatives)alternatives)
Feeling of KnowingFeeling of Knowing
Song LyricsSong Lyrics Somewhere over the rainbow Somewhere over the rainbow Somewhere over the rainbowSomewhere over the rainbow
Way up high,Way up high,There's a land that I heard ofThere's a land that I heard ofOnce in a lullaby.Once in a lullaby. Somewhere over the rainbowSomewhere over the rainbowSkies are blue,Skies are blue,And the dreams that you dare to dreamAnd the dreams that you dare to dreamReally do come true.Really do come true.
Someday I'll wish upon a starSomeday I'll wish upon a starAnd wake up where the clouds are farAnd wake up where the clouds are farBehind me.Behind me.Where troubles melt like lemon dropsWhere troubles melt like lemon dropsAway above the chimney topsAway above the chimney topsThat's where you'll find meThat's where you'll find me
Somewhere over the rainbowSomewhere over the rainbowBluebirds fly.Bluebirds fly.Birds fly over the rainbow.Birds fly over the rainbow.Why then, oh why can't I?Why then, oh why can't I?
If happy little bluebirds flyIf happy little bluebirds flyBeyond the rainbowBeyond the rainbowWhy, oh why can't I?Why, oh why can't I?
WHAT A WONDERFUL WORLDWHAT A WONDERFUL WORLD I see trees of green, red roses too I see them bloom for me and you And I think to I see trees of green, red roses too I see them bloom for me and you And I think to
myself, what a wonderful world I see skies of blue and clouds of white The bright myself, what a wonderful world I see skies of blue and clouds of white The bright blessed day, the dark sacred night And I think to myself, what a wonderful world The blessed day, the dark sacred night And I think to myself, what a wonderful world The colours of the rainbow, so pretty in the sky Are also on the faces of people going by I colours of the rainbow, so pretty in the sky Are also on the faces of people going by I see friends shakin' hands, sayin' "How do you do?" They're really saying "I love you" I see friends shakin' hands, sayin' "How do you do?" They're really saying "I love you" I hear babies cryin', I watch them grow They'll learn much more than I'll ever know And I hear babies cryin', I watch them grow They'll learn much more than I'll ever know And I think to myself, what a wonderful world Yes, I think to myself, what a wonderful world think to myself, what a wonderful world Yes, I think to myself, what a wonderful world Oh yeahOh yeah
