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1. Baddeley's multi-component model a. Consists of 3 components b. Evidence comes from phonological similarity effect, word length effect etc
2. Individual differences in WM (role of WM in fluid intelligence) a. Kyllonen & Christal (1990) - WM tasks and reasoning tasks are highly correlated ?WM underlies the ability to act in an intelligent, goal-directed fashion. b. Conway et al (2002) - the differential contribution of STM and WM to 'g' ?structural equation model c. Duncan et al. (2012) - there might be a more general process than just manipulating information in WM: the construction of a mental program that requires segregating and assembling multiple parts and controlling rules
3. Neurobiology of WM - role of the PFC a. Evidence for the Standard Model Goldman-Rakic (1987) was the first to propose an explicit connection between components of Baddeley's model (Baddeley, 1986) and the sustained delay period activity of individual PFC neurons studied in monkeys (Fuster, 1973). Subsequent results from monkey electrophysiology, neuropsychology, and neuroimaging has led to the "standard model" of WM, which draws explicit connections between PFC areas mediating WM and projections from specific posterior processing areas.Monkey electrophysiology (oculomotor delayed response task)Neuropsychology (lesion patients were unable to remember location/ object for a short period of time)Neuroimaging ('what' vs. 'where' distinction extends into PFC) b. Despite the widespread influence of this WM model, there is controversy with respect to PFC's role: Some researchers specify a domain-general central executive in PFC "directing" (e.g., via mediation of interference and distracters) the "slave" systems in posterior cortical areas.Monkey neurophysiology: mixed sensitivity neurons rather than 'what' vs. 'where', adapting flexibly to task requirements Conflicting evidence: It might be the case that neurons have adapting coding properties, but some of them are more specialized for coding information about location / object properties.Neuroimaging spatial-and non-spatial information is retained in the same part of the PFC during WM task ? problem with fMRI dataThe majority of neurons were selective for the remembered location - PFC neurons are more important for attentional selection than WM per se.Monkey neuropsychology: Monkeys with inferior frontal cortex lesions failed with increased set size, T cortex - impaired in delay taskHuman neuropsychology: PFC impair WM only under conditions of distractionPFC regions activated during manipulation of information, while T/P were sensitive to load (storing) ? the idea of a central executive
4. Distributed neuronal architecture of WM The region holding the templates in WM activate when subject see the images, suggesting that the PFC sends signals to posterior cortical areas to hold representations.
5. WM as an 'emergent property' of the brain ? WM is not accommodated by one or two circuits, but is an emergent property of the brain.
- Coordinated activity of multiple processes
- Items can be encoded by attentional orienting to memorised locations and a motor code specifying the location relative to body.
1. Baddeley's multi-component model a)WM consists of 3 components:
1. Visuo-spatial sketchpad
2. Phonological loop
3. Central Executive a. The "working" component of WM b. Coordinates resources, attentional control, processing and manipulation of stored information b) EvidencePhonological similarity effect ? phonologically similar words (words that sound similar such as cat, fat, bat) are harder to remember than phonologically different words o one is coding these words in the same articulatory code and the capacity if the phonological buffer is limited, so there is a phonological bufferWord length effect- immediate memory span for short words is greater than long wordsArticulatory suppression effect - with visual presentation of words, irrelevant speech removes phonological similarity effect and word length effectPatients with STM deficit show none of the above effects ? when words are presented visually, any kind of residual memory of the presented words must be because they use another route to store the words (perhaps words can be stored visually if we need to do so)
2. Individual differences in WM: Role of WM in fluid intelligence Controversial paper: Reasoning ability is (little more than) WM capacity (Kyllonen & Christal, 1990) a) Kyllonen & Christal (1990) found that WM tasks and reasoning tasks are highly correlated, and concluded that WM underlies the ability to act in an intelligent, goal-directed fashion.
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