1 Components of memory Components of memory and implicit memory PS2011 & PS2016: Cognitive Psychology John Beech

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Components of memory

Components of memory and implicit memory

PS2011 & PS2016: Cognitive Psychology

John Beech

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Components of memory

Overview of the 3 memories

We process information very briefly in its raw form in “sensory memory”. Large capacity. Rapid decay.

Short-term store of limited capacity for period of 15-30 sec. Rehearsal maintains it. Forgetting slow.

Long-term memory has large capacity with very slow decay

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Components of memory: Atkinson & Shiffrin (1986)

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Components of memory: iconic memory

Sensory memory

Neisser (1967): “iconic memory” (E.g. cigarette or sparkler in dark) and “echoic memory” (e.g. saying “what?” and then knowing what was said).

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Components of memory: iconicSperling (1963) – 3-row matrix of letters:·Matrix shown for 100msec and S

recalled “whole report” of 4 letters on average

·Impression of seeing whole array·Matrix shown 100ms again, then tone

signalled top, middle or bottom of array to recall.

·If 67% of row recalled, he argued that 67% of whole array must therefore be available.

Varying probe length showed steep decline in memory to asymptote after only .25 sec.

K V JX P MR V C

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Properties of sensory memory

Large capacity.

Limited only by acuity of retina

Information is mainly unprocessed:

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Sperling (1960): 2 x 4 matrix of letters and digits. When probed for position got usual partial report superiority. But when probed for digits or letters, no partial report superiority. Therefore only the visual representation and its position is stored, not the identity of the items. It appears to be primarily a visual store.

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Components of memory: working memory

Listening to or reading and understanding text involves short-term memory to hold information temporarily while it is being processed. Remembering a phone number before writing it down involves this memory. Known as working memory and can be used visually, spatially, in mental arithmetic, in reasoning and problem solving as well. It is important for transferring information into long-term memory. It works as a temporary holding store during processing. WM is important for several reasons….

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Efficient use of WM probably enhances cognitive functioning

Kyllonen & Cristal (1990):Suggest people with high IQs have extra storage

capacity in working memory.WM appears to be linked to moodTeasdale et al. (1993):Suggested depressed person keeps generating

negative thoughts. In turn affects mood. This sequence is in WM. Should be able to kill cycle by occupying WM with other things.

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Necessary for reading comprehension

Perfetti (1985):

WM has an important role in skilled reading of text. It maintains information in memory during the processing of reading.

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Experiments often artificial when examining it.

Peterson & Peterson (1959):Consonant trigrams (e.g.TDK) followed by a

number (e.g. 765). Counts back in 3s (765, 762, 759…) and recalled trigram on signal Rapid decline to <10% after 18s.

Thus if rehearsal inhibited, decay is rapid…

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Components of memory: Peterson & Peterson (1959)

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Patients with hippocampal lesions (removal of their hippocampus) cannot transfer information to long-term memory. But they can remember information before their operation. The hippocampus appears important in transferring information from WM to LTM

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Evidence for STM-LTM distinction fromGlanzer & Cunitz (1966):Recalling list of words give U-shaped effectExpt 1: varied presentation rate. Improved recall on

start and middle bits, but not on the last part. Slowness helps LTM but not STM.

Expt 2: Immediate recall vs delayed interference (counting): affects only last part showing an effect on “recency”.

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E v id e n c e fo r o p e ra t io n o f in te r fe re n c e : S e r ia l p o s it io n c u rv e

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Recall accuracy

S e r ia l p o s it io n

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Effect of recall delay on the serial position curve

•Delay wipes out the recency effect, but not the primacy effect.

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Changing presentation rate (Expt 1) affects processing in LTM, but does not affect STM. By contrast, distraction that prevents rehearsal (Expt 2) affects STM but not LTM.

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Components of memory: working memory and its capacityMiller (1956) suggested memory is 7 plus or

minus 2 “chunks”. Chunks implies not necessarily discrete items.

Postman (1975): if letters organised into 3-letter syllables, can remember 21 letters.

Letters and digits accord with 7+/- 2, but fewer syllables, still fewer words and fewer sentences.

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Components of memory: working memory and its capacityChase and Ericsson (1978): tested a

person keen on track events. “4729” became 4 min 7.29 sec, as a finishing time. Initially he remembered about 7 finishing times, so could repeat 20-30 digits. After practice eventually he could recall string of 79 digits. After 6 months, switched to letters and back to 6-letter span.

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Components of memory: further work on the recency effect

‘Recency’ used to be considered synonymous with working memory. Last items still in WM and easy to recall. But can produce recency in other ways.

It is possible to get a recency effect after distractors are given: Bjork & Whitten (1974): participant given series of items and each and every one is followed by a 20 sec distractor. Would expect the recency effect to be wiped out, but it is not! Very tedious experiment.

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One can show effect of recency in long term memory

Crowder (1993): People asked to recall American presidents. There is a clear primacy effect and a strong recency effect for Ford, Carter, Reagan and Bush.

Effect also happens for lots of events in episodic memory: holidays, rugby players recalling their matches, recalling car parking. It’s a long-term recency effect.

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Could be explained by distinctiveness. Because of vast store in LTM, we remember better first and last items.

If this is the case, the recency effect may be affected by location in WM, but is also affected by something else. Possibly distinctiveness.

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Conceptualising WMBoxes used to present processes as schematic

presentationDoes one really have something like a desktop?

Transferring information into filing cabinets?This is too static. WM could be activation of long-term

storage areas.Analogy of an orchestra. Most silent but small section

playing. The sound analogous to WM. Overall orchestra represents LTM

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Summary so far of memory components

Sensory memory appears to have a large capacity but information decays very rapidly.

It is a visual process, as it is affected by darkness.

It is unprocessed as processing makes the iconic effect disappear

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Working memory (WM) is longer in duration and transfers information into long-term memory.

• It probably can serve to improve IQ, it can keep a depressed person depressed, it can help reading comprehension

• Evidence suggests it declines rapidly if one is distracted

• Patients with hippocampal damage do not seem to be able to transfer information to LTM

• WM and LTM can be independently manipulated experimentally (Glanzer & Cunitz)

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CriticismsThe recency effect can be shown to occur even after

the use of a distractor and also in LTM.Using boxes may distort our understanding. Some

memory processes may be more dynamic, as illustrated in using the orchestra analogy.

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The Baddeley & Hitch (1974) model

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The Baddeley & Hitch (1974) modelAt the time they thought that experimental work on

STM had not examined the interaction between thinking about something (processing) and memory. So they coined the term “working memory”.

Central part is a central executive that has conscious control over everything.

Has a number of slave systems. These are mundane as they store, but not much else. If anything mentally demanding, the slaves can’t do it, so hand over to the central executive.

Just like when we jot things down

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The Baddeley & Hitch (1974) modelTwo slave systems are the visual-spatial

scratch pad and the rehearsal loop.There is a rehearsal loop from the executive to

the phonological buffer and back.The inner voice (subvocalisation) can run

independently once initiated as speech can be automatic. The buffer is passive and information decays in it. This leaves executive free to process.

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Some WM findings

E.g. If had to say “the” repeatedly, the loop couldn’t operate. Performance falls markedly as inner articulation disrupted.

If repeating “the” and shown complex shapes, no effect.

Similarly, inner ear can be disrupted by noisy conditions. Span goes down with noise. Executive and phonological buffer have disrupted communication.

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Some WM findings

There is a word-length effect. Monosyllabic words have a greater span than 3-syllable words. Obviously, it takes longer to pronounce 3-syllable words.

Those with anarthria have partial or complete loss of articulate speech. Tongue paralysed. They also show word length effect. Actual muscle movements not needed for subvocalisation. Areas involved in planning movement of speech musculature perhaps involved.

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Summary and evaluation of WMIt is of course a theory. We can only infer the

existence of an inner ear or voice. Various types of findings support the theory. For

instance, we can use concurrent articulation, the word-length effect. Findings from neuropsychology.

Good example of a theory in which data could have gone against it. No line of enquiry has been decisive. But has built up an overall picture.

Working memory is a very important system and has a key role in many cognitive aspects and even in mood.

However, the concept of an executive is problematic.

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Long term memory

This is a store with unlimited capacity that holds information for a long period. All that can be remembered is held for virtually a life time, or at least while the brain is capable of retrieval.

It is believed that LTM is organised into components which contain different types of information.

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Long term memory: its parts

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Long term memory: its parts

Declarative vs. procedural memory (Squire 1987). Procedural memory (or implicit memory) is not available for reporting. It has the effects of learning skills and behavioural responses and is unconscious. Declarative memory (or explicit memory) has facts, information, ideas, images, etc. We can retrieve this information and are conscious of it.

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Evidence for the declarative vs procedural distinction

Amnesiacs who have lost much declarative memory (people, places, events) still retain skills – can swim, can play golf, etc.

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Semantic vs. episodic memory (Tulving, 1972, 1983)

Semantic memory is about facts, concepts and ideas; whereas episodic memory is about personal experiences and is temporally dated.

Evidence: Lefrancois (2000) KC plays chess and knows that he can, but cannot remember playing a game.

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Explicit vs implicit memory (or declarative vs procedural memory)

Definition

Explicit memory is basically when conscious memory is used. Implicit memory applies when conscious memory is absent.

Explicit memory: direct memory tests e.g. recall and recognition.

Implicit: priming – indirect testing.

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Implicit and explicit memoryTulving, Schacter & Stark (1982)Ss learned rare words (e.g. “honeycomb”)1hr or 1wk later gave (_o_ey_o_b). ½ were from

learned list and ½ new. Accuracy good over time. Fragment completion task (an indirect test) indicates implicit memory persists quite well.

Recognition memory (testing explicit memory) of the learned list good after 1hr (60%) but poor after 1wk (20%).

Implicit memory persists quite well over time, but recognition memory, testing explicit memory, declines over time.

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Data driven vs conceptually driven

Roediger’s (1990) theory“Data-driven” means evoked by external

stimuli while “conceptually driven” means produced by the person.

Data driven processes are not consciously evoked, so often test implicit memory. Conceptually driven ones test explicit memory.

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Implicit vs. explicit memory

Jacoby (1983): Phase 1: Ss shown word sequence.

XXXX, DARK No context: shown each word without context. They had to read aloud dark.

HOT, COLD Context: shown each (cold in this case) with antonym.

LOW, ???? Generate: Saw only the antonym and had to say aloud high.

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Jacoby (1983): Phase 2

During Phase2 one test involved recognition memory (testing explicit memory) and the other involved perceptual identification (implicit memory).

The perceptual task involved brief presentation of the 1st phase words or new words. Words previously seen (in the no context and context conditions) had been “primed”, so they were identified more easily. As the words were not seen in the generate condition, we would expect poorer performance in the generate condition.

Explicit memory was best in the generate condition, while implicit memory was best in the no context condition.

XXXX, DARK

No context: shown each word without context. They had to read aloud dark.

HOT, COLD

Context: shown each with antonym.

LOW, ????

Generate: Saw only the antonym and had to say aloud high.

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Thus explicit memory, requiring conscious (and active) processes, was best in the “generate” condition, needing the most conceptualisation. But conceptualisation is actually detrimental to implicit memory, which works best in the absence of conscious memory.

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Aspect Implicit Explicit

Conscious memory

Absent Present

Persistence Good Poor

Roediger Data-driven Conceptually driven

Generation task Poor Good

Priming task (no context)

Good Poor

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Implicit vs. explicit memory: evaluation

The data-driven vs conceptually driven distinction is probably an important one.

The distinction involves an element of judgement. Some would argue that most tasks could involve a mixture of the two.

There could be different types of implicit memory. Priming performance on perceptual identification and in fragment-completion was found to be unrelated by Witherspoon & Moscovitch (1989), even though they are both testing implicit memory.

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Implicit vs. explicit memory: a summary

Implicit memory is used when one does not use conscious processes.

We can understand the implicit vs. explicit memory distinction in terms of data-driven and conceptually driven processes. Data-driven processes are “driven” by encountered stimuli not consciously processed.

There are likely to be different sorts of implicit memory.

Documents

1 Components of memory Components of memory and implicit memory PS2011 & PS2016: Cognitive Psychology John Beech