Working memory model

STM

Limited capacity – Limit to how much information can be held • Short duration – Items decay from STM as a function of time and have to be rehearsed to be maintained

Digit span task - number of items recalled immediately in correct order

working memory model

A system that is capable of temporarily holding and manipulating information...a mental work space.” (Baddeley et al., 2015, p42) – a mental workspace used for both storage and manipulation of information • Allows us to perform complex cognitive activities such as reasoning, learning, comprehension Other models see working memory differently: e.g., “Cognitive processes that retain information in an unusually accessible state” (Cowan, 1999 p62) – Temporary activation of a portion of long term memory

Working memory tasks

Backward digit span 7 3 9 2 6 1 8 • OSPAN (Turner & Engle, 1989) – Operation span with words – Retain words while performing calculations • IS (10 ÷ 10) - 1 = 2 ? CLASS • IS (7 ÷ 1) + 2 = 7 ? PAINT • etc

Parts of working memory

visual spatial sketchpad: Logie (1995) •Passive inner cache for storing visual and spatial items •active inner scribe for rehearsal

central executive: Limited attention, controls 2 slave systems, selecting and manipulating material in each

phonoloical loop:•Acoustic or speechbased items •Passive store of limited capacity•Active articulatoryrehearsal process to prevent decay

characteristics of phonological loop

Items in the store are stored in a phonological (acoustic) code. • The phonological store has a limited capacity• The articulatory rehearsal process: – Maintains items in the store – And can recode visually presented items into a phonological form

Evidence that Items in the store are stored in a phonological (acoustic) code.

Phonological similarity effect

Phonologically similar words less well recalled, even when presented visually.

• Phonological similarity effect – Conrad (1964): Similar-sounding letters => lower recall, e.g., BCPTV vs ABIFO –

Baddeley (1966): How about words? Listen…mad, man, mat, cap, cad, can cow, day, bar, few, hot, pen Similar sounding words => lower recall. Supports the proposal that items are stored in a phonological code.

Evidence that The articulatory rehearsal process recodes visually presented items into a phonological form.

Visual (formal) similarity does not have same effect (Baddeley, 1966). Different form, similar sound: bought, sort, taut, caught, wart (hard to recall) rough, cough, through, dough, bough (easier to recall despite similar form) • It is only the sound that matters – evidence for phonological code.

Evidence that The phonological store has a limited capacity.

Word length effect (Baddeley, Thomson & Buchanan, 1975)

You will be shown some words, one by one, for one second each. • Your task is to recall the words in the correct order, when you see this instruction:

Articulatory rehearsal maintains items in the phonological store.

How can we test this? • Use a task designed to prevent rehearsal. • Articulatory suppression: Saying (e.g.) “the” continuously while trying to encode a set of words.

Articulatory suppression: A technique for disrupting verbal rehearsal by requiring participants to continuously repeat a spoken item.Word length effect: A tendency for verbal memory span to decrease when longer words are used. 

Items in the phonological store need to be maintained by a process of subvocal rehearsal.Saying “the” repeatedly occupies the articulatory loop, displacing the studied items.

What effect does the articulary oppression have on our ability to retain the words?

Articulatory suppression occupies articulatory loop: – Leads to lower recall of spoken items, suggesting it disrupts maintenance of items in store. – Prevents recoding of visually presented items.

Saying “the” repeatedly occupies the articulatory loop, preventing visuallypresented items from entering the store.

Evidence that Auditory items have direct access to phonological store while visually presented verbal items (words, letters, digits) have to be recoded into a phonological form

Phonological similarity effect disappears for visually presented items but not for auditory presentation (Baddeley, Lewis, & Vallar, 1984). – These data suggest that auditory information has direct access to phonological store, while visual information needs to be recoded via the articulatory loop.

Auditory items have direct access to the phonological store => phonologically similarity effect. With articulatory suppression, no difference between recall of phonologically similar and dissimilar words when visually presented – equally difficult for these items to enter the store => very low recall for both.

The Phonological Loop and second language learning

PV had a digit span of just two items, but was otherwise unimpaired. She was completely unable to learn words in an unfamiliar language. She had astroke which caused this. She could remember word pairings of her native language Italian

Phonological Loop deficits and Specific Language Impairment (SLI)

SLI: unimpaired non-verbal cognitive skills with significant impairment(s) in language abilities Gathercole & Baddeley (1990): Are phonological loop deficits causally related to SLI? – 8-year-old children with language development of 6-year-olds (SLI) – 8-year-olds with normal language (chronological age match) – 6-year-olds matched for language with SLI group (language match) Nonword repetition test: repeat ‘nonwords’ ranging in length from 1 to 4 syllables

Gathercole and Baddeley 1990: results

Small sample: 6 children with SLI took part. However, the results were very striking; all children with SLI scored below all the typically developing children. Many studies have now replicated these findings. This study has been very influential in suggesting a possible causal explanation for SLI. The Children’s Non-Word Repetition test is now widely used and has been proposed as a behavioural marker of genetically transmitted SLI.

Phonological Loop and language learning in typically developing children

Correlation between nonword repetition performance and vocabulary development in 4- and 5-year-olds (Gathercole & Baddeley, 1989).

summary

Evidence for the phonological loop comes from: – Phonological similarity effect – Word length effect – Articulatory suppression tasks • Phonological loop seems to have a role in language learning.

According to the working memory model of Baddeley and Hitch, the phonological loop consists of:

A passive store of limited capacity, with an active rehearsal process.

The word length effect in short term serial recall

is the finding that people can remember more short words than long words. This is because they can remember as many words as they can say in about 2 seconds.

The word length effect is the finding that people can remember more items in a list composed of short words than a list composed of long words. Baddeley proposed that this was because long words take longer to say so are more likely to decay while waiting to be rehearsed in the articulatory loop. He said people could remember as many words as they could say in about 2 seconds.

What is meant by digit span?

The number of digits that can be recalled in the correct order immediately after hearing them. The typical digit span is longer in some languages than others.

Baddeley, Papagno and Vallar (1988) studied a patient, PV. Which of the following can be said of PV?

PV had a short digit span of around 2 digits,

PV had normal short term visual memory and normal intelligence

What effect does articulatory suppression have on the phonological similarity effect, according to Baddeley, Lewis, and Vallar, 1984?

Under conditions of articulatory suppression, when input is auditory, participants recall sequences of dissimilar words better than sequences of similar words. When input is visual, they recall sequences of similar and dissimilar words equally well.