Lecture 5 definitions Flashcards
Memory
Refers to the processes that allow us to record (encode), store, and later retrieve experiences and information. Memory is proposed to comprise three stages: encoding, consolidation (long-term storage) and retrieval.
It consists of 3 main components: sensory memory, short-term/working memory and long-term memory.
Sensory memory
Briefly holds incoming sensory information. It is composed of iconic storage (<1 sec, visual information) and echoic storage (several seconds, auditory information)
Short-term (working) memory
Holds a limited amount of information temporarily. It is critical for ongoing processing of events and thoughts. It may last for 12-30 seconds, but can be prolonged by rehearsal. Its capacity (number of items) is limited: around 2-7 meaningful items. They can also be chunked (combined into larger units of meaning, e.g., phone numbers). Short-term memory duration is short (a few seconds). Without rehearsal, information is forgotten rapidly.
The short-term/working memory model (WM model)
Consists of the central executive on top and the visuospatial sketchpad, episodic buffer and phonological loop below.
Phonological loop
WM model: stores mental representations of sounds. It maintains information via rehearsal. It refers to a loop in seconds rather than items. This explains why long words are harder to memorise than short words. It is a little voice/sound in our head that helps us remember and manipulate sounds or words.
Visuospatial sketchpad
Stores visual and spatial information
Episodic buffer
Integrates and manipulates information from the phonological loop and visuospatial sketchpad. Words are chunked into meaningful phrases.
Central executive
Directs overall action, controls the focus of attention, and integrates information in the episodic buffer
Long-term memory
Can persist for much longer periods, often for life. However, it must be consolidated to persist for this long.
Primacy effects
Reflects long-term memory: when asked to remember a list of items, the first few things in the list are often easily remembered
Recency effects
Reflects short-term memory: when asked to remember a list of items, the middle and last items in the list are easily forgotten
What types of long-term memory are there?
1) Declarative memory (factual information) which consists of the semantic memory (general knowledge, e.g, capital cities) and episodic memory (personal episodes, e.g., ‘We ate taco’s yesterday’)
2) Procedural memory (skills and habits, e.g., knowing how to ride a bike)
What types of memory encoding (formation) are there?
1) Structural encoding (shallow): general features of a stimulus, e.g., whether the word is written in capital letters or not
2) Phonological encoding (deeper): specific (linguistic) features of an object, e.g., whether the word rhymes with another word or not
3) Semantic encoding (deepest): remembering what the stimulus means
Maintenance rehearsal
Uses structural and phonological encoding. Refers to rote memorisation (habitual repetition) of information
Elaborative rehearsal
Refers to the expansion of a memory that allows one to create different connections with priorly available knowledge (e.g., professional actors do not simply memorise their lines, but imagine themselves being the person whose role they are playing).
What does LTM look like when modelled as an associative network?
Each concept (e.g., red, fire engine, truck, fire) is represented by a node. Lines represent associations between concepts. Shorter lines indicate stronger associations. Activation of one node/network leads to a spreading activation of related concepts. Neighbouring nodes are likely controlled by top-down modulation. Semantic memory can be represented as similar concepts (red + truck => fire engine), whilst episodic memory can be represented as sequences of events (key in ignition => start car => drive to Albert Heijn => buy hagelslag) Associative networks are consistently being updated in response to internal cognition and new experiences. This means that concepts/memories for specific events are not fixed.
Retrieval cue
A retrieval cue is a stimulus (internal or external) that activates information stored in long-term memory. Multiple cues enhance retrieval. Generating multiple associations involves deeper processing. The more cues, the more chances of successful retrieval. An example is a specific scent/smell (e.g., cookies, that remind you of the cookies your grandma used to bake).
Concepts and memories for specific events are not fixed. What can this lead to?
1) Misinformation effect: post-event experiences alter our episodic memory (personal episodes)
2) Source confusion: we recognise something without knowing where we encountered it (déjà vu)
3) False testimony/confessions: people can be convinced something is true based upon altered memory for it
In which 2 ways can retrieval be enhanced?
1) By a similar context to that where encoding occurred (scuba divers that learned words under water, recalled these words better under water than on land)
2) By a similar state/or mood to that where encoding occurred => when you’re angry about something, you’ll remember this event better as it has more adaptive value. Pontine brainstem regions and amygdala are important for this. This can make traumatic events difficult to extinguish.
Name 4 theories as to why we forget.
1) Encoding failure: much of what we sense is not processed deeply enough to commit to memory (lack of attention, deep processing)
2) Decay: physical memory traces (e.g., associative links) reduce with time
3): Motivated: We consciously or unconsciously repress memories. This is a controversial concept.
4) Interference: new memories can obscure/alter older ones. This can either be proactive (previous memories interfere with encoding/consolidation of new ones) or retroactive (new memories interfere with retrieval of older ones).
Amnesia
Refers to a loss of, or inability to form, long-term memories. Two types: retrograde amnesia (previously consolidated memories can no longer be retrieved) or anterograde amnesia (new memories cannot be formed or consolidated). Amnesia can be caused by trauma, disease, surgery or dementia, among other causes.
Post-traumatic stress disorder (PTSD)
A persistent, recurring memory for traumatic events, leading to chronic stress and anxiety.
Dementia
The - usually age-related - progressive decline in cognitive ability. Particularly in Alzheimer’s type dementia, this decline often begins with a loss in ability to retrieve long-term memory. Alzheimer’s pathology starts in the pontine brainstem, proceeds to hippocampus and gradually (over many years) to the rest of cortex.
