Problem 2 - Memory Flashcards
Magical number 7 - miller’s article
- we can hold only a limited number of items/chunks of information in the STM (7±2)
- chunk: memory unit of several components that are strongly associated with one another.
- behaviorism: emphasis on observable external events.
STM capacity limits: brown/Peterson and Peterson technique
- task: presented with items they should remember, distracting task to prevent rehearsal and recall task.
- materials stored for less than 1 minute is frequently forgotten
STM capacity limits: serial position effect
- U shaped relationship between word’s position in a list and its probability of recall.
- recency effect: better recall for items at the end of the list.
- primacy effect: better recall for items at the beginning of the list.
STM capacity limits: semantic similarity
- experiment wiht digits and words
- pro-active interference (PI): trouble learning new material due to interference of old material. Release can be done via semantic change.
- retro-active interference (RI): past learning is forgotten and you can remember new knowledge easily.
- semantic factors influence number of items that can be stored.
- degree of semantic similarity is related to the amount of interference
Working memory: overview
- baddeley and hitch 1974
Components:
1. Central executive - attentional system
2. Phonological loop - speech processing
3. Visuospatial sketchpad - visual processing
4. Episodic buffer - temporary storage for integrated information
- all components have limited capacity and function independently
Assumptions:
1. Multitasking (duality): two tasks use the same component, they cannot be performed successfully
2. Multitasking (uni-model): two tasks use different components, can perform successfully.
Working memory: phonological loop
- passive: speech perception
- articulatory: speech production (rehearsal)
- phonological similarity effect: reduced immediate recall when words are similar, unsure if its because of acoustic similarity (sounds) or articulatory similarity (articulatory movements).
- word length effect: word span is greater for short words.
Working memory: visuospatial sketchpad
- visual processing: what and left hemisphere
- spatial processing: where and right hemisphere
- visual cache: visual form and color
- inner scribe: spatial and movement and involved in rehearsal.
Working memory: evaluation of visuospatial sketchpad
much remains unknown:
- seperatedness of the visual and spatial component
- interaction between visuospatial sketchpad and episodic buffer
- rehearsal processes within the visuospatial sketchpad.
Working memory: central executive
- attentional system, most important and versatile.
- involved in complex cognitive activities but does not store information.
- prefrontal cortex is most active
- 4 processes: focusing attention, dividing attention between stimulus streams, switching attention between tasks and interfacing with LTM.
Working memory: miyake et al’s executive functions (theoretical approach)
To identify the number and nature of executive processes. 3 executive processes: inhibition, shifting and updating.
1. Updating = common EF + updating specific abilities
2. Shifting = common EF + shifting specific abilities
3. Inhibition = common EF
the unity/diversity framework:
- each excutive function consists of whats common to all three + whats unique
- Common EF: one’s ability to actively maintain task goals and goal-related information and use this information to effectively bias lower-level processing.
- diversity evidence: each executive function had a specific brain area + a common brain area (left lateral pre-frontal cortex).
Working memory: dys-executive syndrome
- impaired central executive
- impaired response inhibition, rule deduction and generation, maintainance and shifting of sets etc.
- flawed model: each executive process is associated with a different region within the frontal cortex so the syndrome affects everyone differently.
Working memory: central executive evaluation
- based on both behavioral and neuro-imaging evidence
- dys-executive syndrome is misleading
- limitations: task-impurity problem (hard to identify the contribution made by any specific executive process), number and nature remains unclear.
Working memory: episodic buffer
- holds integrated information about episodes or events in a multi-dimensional code combining visual, auditory and other sources of information.
- buffer between other components of the memory system
- links WM to perception and LTM
- capacity is approximately 4 chunks
Working memory: episodic buffer evaluation
- storage facility
- passive structure
- limitations: separate inputs (unclear how information is combined), research on other sensory modality is lacking (smell and taste).
Working memory: overall evaluation
