Cognitive ScienceCognitive ScienceJose TabaresJose Tabares

Psych 202B Psych 202B

January 23, 2006January 23, 2006

Creating False Memories:Creating False Memories:Remembering Words Remembering Words Not Presented in Lists.Not Presented in Lists.

Henry L. Roediger IIIHenry L. Roediger IIIandand

Kathleen B. McDermottKathleen B. McDermottRice UniversityRice University

Journal of Experimental Psychology:Journal of Experimental Psychology:Learning, Memory, and CognitionLearning, Memory, and Cognition

1995, Vol 21, No.4, 803-8141995, Vol 21, No.4, 803-814

False MemoriesFalse Memories

Remembering events that never Remembering events that never happened. happened.

Or, remembering them quite differently Or, remembering them quite differently from the way they happened.from the way they happened.

Reconstructing MemoriesReconstructing Memories

Sir Frederic Bartlett, a prominent English Sir Frederic Bartlett, a prominent English psychologist.psychologist.

Had his subjects read “War of the Ghosts”Had his subjects read “War of the Ghosts” Subjects read the story twice and waited Subjects read the story twice and waited

15 minutes.15 minutes. Then they were asked to write down the Then they were asked to write down the

tale as best they could recall it. tale as best they could recall it.

War of the GhostsWar of the Ghosts

So what did Bartlett find?So what did Bartlett find? Subjects frequently changed the story.Subjects frequently changed the story. Bartlett concluded that the subjects Bartlett concluded that the subjects

reconstructed the story to fit with their reconstructed the story to fit with their established schemas.established schemas.

Reproductive memoryReproductive memory Reconstructive memoryReconstructive memory

Elizabeth LoftusElizabeth Loftus

Misinformation EffectMisinformation Effect

DefinitionsDefinitions

Hits (Hits (HitHit) – number of words from List A ) – number of words from List A recognized (out of 15) recognized (out of 15)

Correct Rejections (Correct Rejections (CRCR) – number of words ) – number of words not on List A that were correctly identified as not on List A that were correctly identified as not being on the list. not being on the list.

Misses (Misses (MissMiss) – number of words on the list ) – number of words on the list that were not recognized. that were not recognized.

False Alarms (False Alarms (FAFA) – number of words ) – number of words indicated as being on the list that were, in indicated as being on the list that were, in fact, not. fact, not.

Roediger and McDermottRoediger and McDermott

Two experiments Two experiments Modeled after J. Deese’s 1959 study.Modeled after J. Deese’s 1959 study. Sweet: sour, candy, sugar, bitter, good, Sweet: sour, candy, sugar, bitter, good,

taste, tooth, nice, honey, soda, chocolate, taste, tooth, nice, honey, soda, chocolate, heart, cake, tart, and pie.heart, cake, tart, and pie.

First recall test First recall test Then recognition test.Then recognition test.

SummarySummary

Studies of memory suggest that people Studies of memory suggest that people can have the subjective experience of can have the subjective experience of remembering an event that never actually remembering an event that never actually occurred. This happens either when occurred. This happens either when people mistakenly associate a memory people mistakenly associate a memory with the wrong source, or when they have with the wrong source, or when they have seen so many things consistent with the seen so many things consistent with the event that the event that did not happen is event that the event that did not happen is somehow represented as well. somehow represented as well.

Contextual Prerequisites for Contextual Prerequisites for Understanding:Understanding:

Some Investigation of Some Investigation of Comprehension and RecallComprehension and Recall

John D. Bransford and Marcia K. JohnsonJohn D. Bransford and Marcia K. Johnson

State University of New York, Stony BrookState University of New York, Stony Brook

Journal of Verbal Learning and Verbal Behavior, 11, 717-726.Journal of Verbal Learning and Verbal Behavior, 11, 717-726.

Tree structure of a sentenceTree structure of a sentence

Sentence

Noun phrase Verb phrase

Adjective Noun Modal Verb Noun phrase

Visiting Relatives can be

article noun

a nuisance

ComprehensionComprehension

Involves the recovery and interpretation of the Involves the recovery and interpretation of the abstract deep structural relations underlying abstract deep structural relations underlying sentences.sentences.

One type of error occurs because the act of One type of error occurs because the act of comprehending sentences often includes comprehending sentences often includes plausible inferences, and the results of these plausible inferences, and the results of these inferences may be indistinguishable in memory inferences may be indistinguishable in memory from information actually given (Bransford, from information actually given (Bransford, Barclay, and Frank, 1972).Barclay, and Frank, 1972).

ExampleExample

Three turtles rested on a floating log and a Three turtles rested on a floating log and a fish swam beneath it.fish swam beneath it.

Subjects create semantic products that are Subjects create semantic products that are a joint function of input information and a joint function of input information and prior knowledge. prior knowledge.

Experiment 1Experiment 1

““Would subjects who receive appropriate Would subjects who receive appropriate prerequisite knowledge be able to prerequisite knowledge be able to comprehend the passage quite easily, and comprehend the passage quite easily, and hence would subsequently be able to hence would subsequently be able to recall it relatively well.”recall it relatively well.”

Acquisition phase followed by two tasks—Acquisition phase followed by two tasks—

comprehension rating and recall.comprehension rating and recall.

MethodsMethods

Five groupsFive groups

-No Context-No Context

-No Context 2-No Context 2

-Context After-Context After

-Partial Context-Partial Context

-Context Before-Context Before

ResultsResults

Context Before Group had the best recall Context Before Group had the best recall and rated the passage easier to and rated the passage easier to comprehend than the other groups. comprehend than the other groups.

Experiments 2Experiments 2

Experiment 2 heard one a shorter version Experiment 2 heard one a shorter version of a passage on washing clothes.of a passage on washing clothes.

Three groupsThree groups

-No Topic-No Topic

-Topic Before-Topic Before

-Topic After -Topic After

Experiment 3Experiment 3

Experiment 3 heard a passage similar but Experiment 3 heard a passage similar but longer than the groups in Experiment 2. longer than the groups in Experiment 2.

Only two groupsOnly two groups

-Topic Before-Topic Before

-Topic After-Topic After

Experiment 4Experiment 4

The groups in Experiment 4 heard a The groups in Experiment 4 heard a passage on making a kitepassage on making a kite

Again, three groupsAgain, three groups

-No topic-No topic

-Topic before-Topic before

-Topic After-Topic After

ResultsResults

Both in Experiment 2 and 3, the Topic Both in Experiment 2 and 3, the Topic Before groups rated the passage easier to Before groups rated the passage easier to comprehend than the other group(s).comprehend than the other group(s).

Also, then showed better recall.Also, then showed better recall.

Similar results occurred in Experiment 4.Similar results occurred in Experiment 4.

DiscussionDiscussion

Prior knowledge for a situation does not Prior knowledge for a situation does not guarantee its usefulness for guarantee its usefulness for comprehension. comprehension.

For maximum benefit, the appropriate For maximum benefit, the appropriate information must be present during the information must be present during the ongoing process of comprehension. ongoing process of comprehension.