Psyc 1002 Dr Caleb Owens

Cognitive Processes

Lecture 4 :

The structure of long term memory

Fig. 7-26, p. 288From Weiten, 2007

Explicit Memory: Episodic memory

• Your memory of your life history– Important occasions: birthdays, weddings,

tragedies, achievements– Specific memories of learning new things– Memory of what happened each day, each

month, each year

• Some people have an intact memory for the explicit meaning of concepts, but amnesia for the source of the meaning

Explicit memory: Semantic Memory

• Explicit knowledge of the meanings of words, facts, ideas

• A sense of ‘knowing’ rather than remembering

Hierarchical network models Collins & Quillian (1969); Collins & Loftus (1972)

• Logical hierarchical structure with interconnected “nodes” – eg. canary, bird, animal– and ‘properties’ eg is yellow, has wings, breathes

• Cognitive economy– each concept/ property only stored once => no redundancy

• Properties stored at highest level of network • Spreading activation retrieves meanings

– presenting a concept leads to “activation” of the appropriate node and to a spread of activation to related nodes

Diagram from: http://falcon.jmu.edu/~westrf/cognitive/semantic_memory.html

Evaluation of hierarchical model• Sentence Verification task: Measure time to verify sentences

– “Is this true?” • A robin is a bird• A robin can breathe• A robin can swim

• If two concepts are related, spreading activation from two concepts will “intersect”

• Time to verify sentence depends on distance between concepts (plus time to evaluate intersection)

• Sentence verification time a function of distance between concepts in hierarchical network (Collins & Loftus, 1972)

Diagram from: http://falcon.jmu.edu/~westrf/cognitive/semantic_memory.html

Evaluation of hierarchical model• Collin’s & Loftus (1972) also proposed that as well as the

semantic distance between nodes, time to verify was affected by:– the strength of the initial activation,

– the amount of time since the initial activation

• Which sentence would be verified fastest?• A kookaburra is a kookaburra• A kookaburra is a bird• A kookaburra laughs• A kookaburra can fly

• BUT Typicality effects– A penguin is a bird > A robin is a bird– ie. people take longer to make decisions about less typical examples

• AND Category size effects– A dog is a mammal > A dog is an animal

• These findings are inconsistent with the assumptions of a hierarchical organisation of knowledge

Associational network models Propositional network models

Sources

Phobia: ttp://www.mtsu.edu/~sschmidt/Cognitive/semantic/phobia.jpg Susan: http://www1.harenet.ne.jp/~waring/papers/i1.JPG

From Gray, 2003; see Weiten, 2007 p.272

Fig. 7-12, p. 270From Weiten, 2007

The structure of memory: Schemas & Scripts

• Schema: generalized mental representations, or concepts, describing a class of objects, people, scenes or events

Schema & stereotype examples

• Psytrek Exercise 6b

• Stereotypes examples: burglar, terrorist, Aussie, gender stereotypes

• Marketing to ‘Tweens’– Includes excerpt from “Consuming Kids”

(30:00 to 35:00, full video is available on webCT)

• Racial stereotypes

Associational network models

How do we develop them ?

-experience

-the media

From Gray, 2003; see Weiten, 2007 p.272

The structure of memory: Schemas & Scripts

• Schema: generalized mental representations, or concepts, describing a class of objects, scenes or events

• Individuals’ schemas can be tapped implicitly with Implicit Association Tasks (IAT), word association tasks, priming tasks etc. Refer to PSYC 1001 Prejudice tutorial

The structure of memory: Schemas & Scripts• Scripts: generalized

mental representations of events in time

• Birthday party scripts, Wedding Scripts, Dining Scripts

• Bartlett’s (1932) “The war of the ghosts”

War of the GhostsOne night two young men from Egulac went down to the river to hunt seals and while

they were there it became foggy and calm. Then they heard war-cries, and they thought: "Maybe this is a war-party". They escaped to the shore, and hid behind a log. Now canoes came up, and they heard the noise of paddles, and saw one canoe coming up to them. There were five men in the canoe, and they said:

"What do you think? We wish to take you along. We are going up the river to make war on the people."

One of the young men said,"I have no arrows." "Arrows are in the canoe," they said. "I will not go along. I might be killed. My relatives do not know where I have gone. But

you," he said, turning to the other, "may go with them." So one of the young men went, but the other returned home. And the warriors went on up the river to a town on the other side of Kalama. The people

came down to the water and they began to fight, and many were killed. But presently the young man heard one of the warriors say, "Quick, let us go home: that Indian has been hit." Now he thought: "Oh, they are ghosts." He did not feel sick, but they said he had been shot.

So the canoes went back to Egulac and the young man went ashore to his house and made a fire. And he told everybody and said: "Behold I accompanied the ghosts, and we went to fight. Many of our fellows were killed, and many of those who attacked us were killed. They said I was hit, and I did not feel sick."

He told it all, and then he became quiet. When the sun rose he fell down. Something black came out of his mouth. His face became contorted. The people jumped up and cried.

He was dead.

Bartlett (1932)

• Transformations people made

– 'Something black came from his mouth' tended to become 'he frothed at the mouth', 'he vomited' or 'breath escaped from his mouth'.

– 'Hunting seals' tended to become 'fishing'.

– 'Canoe' tended to become 'boat' and 'paddles' to become 'oars'.

– The wounded Indian tended to become the hero, whose wounds were sometimes even 'bathed' at the end.

– The reference by the Indian who stayed to the possibility of getting killed tended to be downplayed or dropped, whilst the reference to the probable anxiety of his relatives was usually given greater emphasis (the reference to having no arrows was often omitted).

– The role of 'the ghosts' (for some, they become a clan called the Ghosts; for others they were simply imagined by the Indian when wounded).

Bartlett (1932)

• Hard to interpret items were omitted, including: – hiding behind the log;

– the connection between the Indian's injury and the termination of the battle.

Bartlett (1932)