PSYC1002 Lecture Notes - Lecture 5: Daniel Schacter, False Memory, Implicit Memory
19 May 2018
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Ch 7 Weiten p291-7 AND
Forgetting is adaptive
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Needed to forget information no longer relevant
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Forgetting can reduce competition among memories that would otherwise cause
confusion
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Daniel Schacter 1999
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Use brain-imaging technology to track neural markers of cognitive effort in a series of
tasks in which participants memorised pairs of words
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Found forgetting word pairs deemed "irrelevant" made it easier to remember the
"relevant" word pairs and reduced the "demands" place on crucial neural circuits
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Found forgetting helped subjects remember the info they needed to remember
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Kuhl et al 2007
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Still unknown why people forget information they'd like to remember
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Forgetting can be caused by defects in encoding, storage, retrieval, or some combination of
these processes
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Nonsense syllables - consonant-vowel-consonant arrangements (e.g. BAF, XOF)
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Worked with meaningless materials which would be uncontaminated by his previous
learning
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Tested memory of lists after various time intervals
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Forgetting curve - graphs retention and forgetting over time
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Shows drop in retention during first few hours after memorisation of nonsense syllables
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Concluded most forgetting occurs very rapidly after learning something
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Screen clipping taken: 7/08/2017 10:53 PM
Worked with meaningless material
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Found when subjects memorise more meaningful material e.g. poetry, forgetting
curves not as steep
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Problems with study
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Ebbinghaus's Forgetting Curve (how quickly we forget)
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Retention = proportion of material retained
Measures of forgetting
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Forgetting
L5 - Implicit and false memory
Monday, 7 August 2017
10:19 PM
Cognitive Page 1
Retention = proportion of material retained
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Retention and forgetting measured together
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Retention interval = length of time between presentation of materials to be
remembered and measurement of forgetting
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Recall - reqs subjects to reproduce info on their own with no cues (e.g. write down
as many words as you can remember)
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Recognition - reqs subjects to select previously learned info from an array of
options (shown list of 100 and asked to choose the 25 words you memorised,
subjects have cues and answers, e.g. multiple choice)
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Relearning - reqs subject to memorise info a second time to determine how much
time or how many practice trials are saves by having learned it before (savings
scores provide an estimate of their retention
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3 measure methods (Lockhart 1992)
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Luh 1922
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Nonsense syllables with both recognition and recall test
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Recognition tests especially sensitive measures of retention OR easy
measures of retention
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Explanation of results
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Evidence shows recognition measures tend to yield higher scores than recall measures
of memory for the same info
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Info initially never inserted into memory
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Pseudoforgetting
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e.g. you thinking you know what a coin looks like
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Pseudoforgetting usually attributed to lack of attention
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Memory codes may be formed, but not effectively or appropriately
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Phenomic encoding - distracted while reading
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Semantic encoding (more effective)
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Ineffective coding
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Attributes forgetting to the impermanence of memory storage
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Decay theory - forgetting occurs because memory traces fade with time
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Assumes decay occurs in the physiological mechanisms responsible for memories
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Time -> forgetting
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Decay contributes to loss of information from the sensory and short term memory
stores
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NOT yet able to show that decay causes LTM forgetting
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Researchers found the time passage not as influential as what happens during the
time interval for LTM
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Forgetting depends on the amount, complexity and type of info which subjects
have had to assimilate during the retention interval not on the amount of time
passed
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Interference - negative impact of competing info on retention
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Decay
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Proposes people forget info because of competition from other material
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Demonstrations of decay in LTM still elusive
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Researchers control interference by varying similarity between original
material and material studies in intervening period
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Interference assumed to be greatest when intervening material is most
similar to test material
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Decreasing similarity -> reduced interference and less forgetting
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Subjects memorise test material of list of two-syllable adjectives
Varied similarity of intervening learning by having subjects then
memorise 1 of 5 lists
Lists contained synonyms of test words, antonyms, unrelated,
nonsense syllables, numbers
McGeoh and McDonald 1931
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Studies shown interference influences forgetting
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Interference
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Why we forget
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Cognitive Page 2
Document Summary
Forgetting can reduce competition among memories that would otherwise cause confusion. Use brain-imaging technology to track neural markers of cognitive effort in a series of tasks in which participants memorised pairs of words. Found forgetting word pairs deemed irrelevant made it easier to remember the. relevant word pairs and reduced the demands place on crucial neural circuits. Found forgetting helped subjects remember the info they needed to remember. Still unknown why people forget information they"d like to remember. Forgetting can be caused by defects in encoding, storage, retrieval, or some combination of these processes. Nonsense syllables - consonant-vowel-consonant arrangements (e. g. baf, xof) Worked with meaningless materials which would be uncontaminated by his previous learning. Tested memory of lists after various time intervals. Forgetting curve - graphs retention and forgetting over time. Shows drop in retention during first few hours after memorisation of nonsense syllables. Concluded most forgetting occurs very rapidly after learning something.
