Human Memory Flashcards
Multi-Store Model
Sensory and long-term memory (LTM) are actual stores
Working memory (WM) is not an actual store
- Subset of sensory and long-term stored information that becomes activated for conscious processing
- Also called “short-term memory” (STM) but Wm captures better that this a subset of memory activated “to work on”
- Perfectly fine to use “STM” when the emphasis is on the short-term nature of available information
Working Memory and Attention
- Working memory retains information for a brief period while performing mental operations on that information
- Attention is the process of focusing our awareness on a particular goal or information
a. A goal we have in mind, or stored information we think about
b. Information in the world, something we see or hear and focus on
What is working memory directly related to?
Attention
- Contains information selected by the current focus of attention
- Information brought to the foreground of our awareness
- Literally, bits of information “fired up” in the brain
- Can be triggered by perception, or by thought
Structure of Working Memory
- Central executive coordinates attention, makes decision, triggers action
- Phonological loop processes speech, language and sound
a. Inner voice that repeats speech input to keep longer in store
b. Also transforms visual language into phonological representation - Visuo-spatial sketchpad processes visual and spatial information
- Similarly, a visual representation for the “inner eye”
- Episodic buffer processes episodic information / experiences
Working Memory has limited capacity
- Working memory can only store a very small number of items
- Only 3 or 4 items if they are random - More, if they have some connection (words in a sentence / items that share features or are in some pattern)
- “the magical number of seven plus minus two”, Short-term memory of 5 and 9 digits/word
Chunking
- The limit is the number of items (“chunks”), not the amount of information
- A long word can be remembered more easily than a sequence of letters (if it is a familiar word)
- Chunking: combining information into chunks
- Smaller pieces of information can be combined and memorized in larger chunks (fewer items)
- For example phone numbers, as 4 chunks of double-digits
- FMLWTFBRB memorized as chunks FML WTF BRB
- Representation matters
- Same information can be encoded differently
- Some representations easier to remember than others, e.g. names/word instead of numeric codes
Working memory is volatile
- Information is only available for a brief period
- “Refresh” in the phonological loop and/or visual sketchpad requires unbroken attention
- Around 10 sec, up to 20-30s
- Information is easily lost from working memory
- Displaced when we shift attention from one (sub-) task to the next
- Depends on how many ‘memory slots’ the new task needs
- Distractions that break out concentration
- Forgetting what we wanted to do
- Mild wandering
Structure of Long-Term Memory
Encoding
Forming a mental representation of an experience
- Memory is formed from experience
- Can be encoded in different ways
Storing
Forming associations
- Reinforced by reactivation (learning, rehearsing)
- Features associated with an experience might not be reinforced in the same way (e.g. learning how to use a system operation, but not remembering through which menu it can be accessed)
Retrieval
‘fetching’ stored memory for processing in working memory
- Recognition: retrieval triggered by perception (seeing or hearing something similar to what is stored)
- Recall: retrieval by “memory search” based on mental cues
Storage: Semantic network
Retrieval: Activation of Memory
Activation: how easily a chunk of information can be retrieved from memory
Influenced by three factors:
1. Practice: how many times a chunk has been used in the past (More easily retrievable when used frequently)
2. Recency: how recently a chunk has been used (More easily retrievable when used recently)
3. Context: what is present in the person’s focus of attention (More easily retrievable when associated with information in working memory)
Recognition
- Recognition is easy
- Retrieval aided by external information
- Perception provided cues for matching against stored information
- For example, recognising faces in a fraction of a second
- Reactivation of a stored pattern of features
- Depends on context
Recall
- Recall is hard
- Memory search without external help
- Fewer cues: only what we can think of “search terms”
- Easier when stored information is associated with variety of cues through which it can be reached
Example: macOS Spotlight
- Combination of search and browsing
- Supports recall based on search terms
- Supports recognition by showing results with multiple cues
- Categories
- Icons
- Names
- Recognition also supported by preview of content
