Chapter 8:
STM duration
STM duration lasts for approx. 12-30 seconds providing there is no interference. Interference= when new information enters the STM and pushes out information to replace it
LTM - Integration
Cooking a spaghetti Bolognese can involve different types of LTM. Procedural memory is involved in knowing how to brown the meat. Remembering the recipe involves semantic memory. Your memory of time and place of previous cooking disaster with the same dish involves episodic memory.
Alternative Models for explaining human memory
Baddeley & Hitch's Working memory (STM)
Models for explaining human memory: Organisation of long-term memory
LTM is the relatively permanent memory system that holds vast amounts of information for a long period of time. Despite the vast amount of information stored in LTM, it is organised to enable efficient retrieval of information. Using cues (prompts), retrieval may be intentional/unintentional **only the specific information relevant to the cue is retrieved, not the entire contents of LTM. Difficulty in retrieval of information may be due to poor organisation of information during encoding & storage, or failure to use an appropriate retrieval cue. Forgetting occurs when information in LTM cannot be retrieve for some reason, not that the memory has disappeared. LTM primarily stores information semantically, in terms of its meaning.
The Atkinson - Shiffrin multi-store model
Long-term memory store (LTM) holds information relatively permanently in a highly organised way. unlimited capacity information stored for a lifetime and does not decay retrieval of information may be disrupted by inefficient search methods (retrieval cues) or interference
Long-term memory types
PROCEDURAL (implicit) MEMORY: Learned actions & skills memory of actions and skills that have been learned previously, i.e. memory for knowing 'how to do something'. Procedural memories cannot always be consciously activated and communicated.
Memory:
Storage and retrieval of an image, concept or knowledge, when the original stimulus no longer exists in consciousness
Storage: Retaining information
Storage is organising and retaining information in the brain over time so we can use it later. Duration and capacity in the human memory system vary. The process of storing information is a selective process. Our memory systems would be overloaded if they had to retain information about every moment in our lives.
Levels of processing
The more complex the processing within each level, the stronger the memory. The more effort we put into remembering something the stronger the recall (Tyler et al 1979) Eg. Easy anagrams vs complex anagrams Relating words to items of personal relevance (things we know and care about) leads to stronger recall (Rogers et al 1977) Eg. "Does this word relate to you/ your mother?" produces better recall than "What does this word mean?"
Models for explaining human memory
Craik and Lockhart - Levels of processing
Types of LTM
DECLARATIVE (explicit) MEMORY: Memory of specific facts or events that can be brought consciously to mind and usually communicated. i.e. memory of 'knowing that'. The two types may interact (distinction not clear-cut) Two types of declarative memory: EPISODIC MEMORY: Time & place Declarative memory system that stores information about specific or autobiographical events. i.e. personal life experiences - providing information about the where and when of particular events we have experienced in the past. Retrospective memory: remembering past events Prospective memory: remembering things to do in the future SEMANTIC MEMORY: Facts Declarative memory system that involves general information about the world, including our specialised knowledge in areas of expertise.
Encoding: Getting information in
Encoding is the process of converting information into a useable form or 'code' so that it can enter and be stored in memory. Information is received, converted from its raw sensory state to a form that the brain can use or process, and stored in memory. Improving the quality and depth of encoding can improve memory
Sensory Memory (Atkinson - Shiffrin)
First stage of memory. Information in our environment is received. Relates to memory in our sense organs: we have a sensory store (sensory register) for each of our five senses Unlimited storage Information held in sensory memory has not yet entered our awareness. Unique, interesting, relevant information attracts attention from our senses If we don't pay attention to the information, it is NOT processed. Information is briefly stored then fades and decays - gone forever. Each sensory store varies in duration (millisecond to several seconds) -Rapid Decay- long enough for us to attend to and select important information to transfer to STM (Short Term Memory) (eg. Long enough to begin encoding); This stops us being overwhelmed by huge amounts of sensory input and allows us to move on to new incoming information.
Sensory Memory - Iconic Memory
Iconic Memory refers to visual sensory memory. Last for about 0.3 seconds. Images are retained just long enough to recognise and process the sensory information. Films: 64 frames per second.
1. Phonological Loop - Verbal working memory (Baddeley & Hitch) { refer to images for other step 2 & 3 }
Auditory Working Memory Used when you read, listen, speak or repeat words Storage of what we hear (articulatory rehearsal loop) Retains words from beginning of sentence until we have heard the end - so we can understand Stored in a sound-based or phonological form Sub-vocal maintenance rehearsal - repeating it internally on loop Without rehearsal, duration of 2 seconds Eg. Try to remember list but say something else Eg. Word length effect - longer words can be harder to remember, longer to rehearse
CRITICISMS & STRENGTHS Craik and Lockhart's levels of processing framework
Criticisms The concept of level, or depth, has proved difficult to quantify and measure. There are no generally accepted ways of measuring different levels of processing in valid and reliable ways. Strengths of Framework The concept of deep processing leading to more effective encoding and better memory for new information is widely accepted and has many practical applications. Practical application for studying: understand new information by restating it in your own words; actively question new information think about potential application and implications of material; relate new material to what you already know; generate your own examples of a concept - all use elaborate rehearsal!
Criticisms of the Atkinson Shiffrin Multi-Store Model
Doesn't adequately explain the interaction between the different memory stores. Eg. LTM must actually interact with STM because chunking is most successful when meaning is given to material that is chunked Eg. LTM may help us determine which info to pay attention to in Sensory memory The model doesn't show why coding of information changes between the different memory stores. It sees clear distinctions between STM and LTM where other models view memory on a continuum.
Framework of Craik and Lockhart theory { refer to image }
During learning, the level or depth at which information is processed determines how well it is stored in LTM. deep processing result in more effective encoding and better memory for new information has many practical applications memories are best encoded, organised and stored in LTM by meaning. There is a continuum of levels of processing from shallow to deep. Shallow processing - focus at the basic level, the information's physical or sensory attributes Intermediate processing - the stimulus primarily encoded according to its acoustic/phonetic qualities Deep processing - encoding that links new information with information already stored in LTM, in interrelated networks of categories & subcategories The concept of level is difficult to quantify and there are no generally accepted means of measuring different depths of processing in valid and reliable ways.
STM - Chunking (increase capacity)
Getting around the limited capacity of STM Miller (1956) demonstrated that STM has capacity 7+/-2 items, but could be increased through chunking; thus storing 7+/-2 groups of items grouping separate bits of information into larger units that can be remembered as single units making large amounts of information more manageable. capacity of STM is about seven bits/chunks of information increasing the amount of information in each chunk can increase this amount. **chunking is even more effective when the chunk has greater meaning or importance, eg. 2014 - the year you finish high school or the year you were born.
Sensory Memory - Echoic Memory
Have you ever asked someone to repeat their question but then realised that you DID hear it after all? Brief memory of what you just heard processes auditory sensory information providing a smooth, integrated and continuous experience of auditory information. stores sounds in their original sensory form for up to 3 ─ 4 seconds to allow for understanding of speech. If echoic memory storage were as short as iconic memory storage, speech might sound like a series of separate, distinct sounds instead of words or phases.
Semantic Network Theory
LTM contains thousands of concepts, each with very many connections - an effective storage, or 'filing', system that enables efficient and effective retrieval of information. Semantic network theory proposes that information in LTM is organised systematically in the form of overlapping networks of concepts and units of information that are interconnected and interrelated by meaningful links. A semantic network consists of nodes representing concepts, joined together by pathways that link related concepts - organised in a hierarchy according to particular concepts. Nodes Represent the concepts. Each node is linked with a number of other nodes. As we retrieve information, the activator of one node causes other related nodes to be activated. Links (pathways) Lines connecting the nodes are pathways; pathways (can be labelled) show how the concepts are related to one another. The length of each pathway represents the degree of association between two concepts. Shorter pathways imply stronger associations and therefore quicker retrieval times. Example: Qantas Map - cities are the nodes - arrows between the cities are the flight pathways Retrieval of information from LTM starts with searching a particular region of memory and tracing associations for links in that region rather than randomly searching the whole LTM (like using Google as a search engine)
Evidence to support the Atkinson-Shiffrin Multi-Store Model: Patients with Brain Damage
Patients with anterograde amnesia have provided evidence for a difference between Short and Long - term memory. Damage to hippocampus Can only remember up to the time of the head injury Can perform activities learnt prior to the injury Can form new procedural memories (simple skills) Unable to form new declarative memories (facts or events). Shown in free recall tests where they have good recency effects but poor primacy effects.
STM - Maintenance Rehearsal (increase duration)
Maintenance rehearsal involves simple, rote repetition of information, to retain that information in STM Verbal (saying words out loud) Sub-vocal (thinking words silently to oneself) Visualising (keeping pictoral image in mind) Muscular (imaging how ii feels to perform action) It does not add meaning to the information or link it with other information in LTM. Once maintenance rehearsal stops information will be lost within 12-30 seconds. However, if we repeat something often enough it may be transferred to LTM. Provided maintenance rehearsal is not interrupted, information can be retained indefinitely in STM.
Craik and Lockhart
Memory is a continuous dimension in which memories are encoded and related to the ease with which they can be retrieved. Levels of processing refers to: the number and type of associations made between new knowledge and previous knowledge. Craik and Lockhart's levels of processing framework proposes that the level, or depth, at which we process information during learning determines how well it is stored in LTM. The deeper the processing (encoding) of information, the greater the chance of it being understood and remembered later (retrieved).
The Atkinson - Shiffrin multi-store model
Memory is described as a system of multiple memory levels that operate independently and simultaneously, and interact in many ways. Sensory memory, STM and LTM are separate but interrelated systems. The flow of information moves in stages through each component: each component represents a place where information is held and processed each component stores, encodes and processes information in different ways but they operate simultaneously and interact
Key functions of memory:
Memory performs three key functions - the conversion, or encoding, of information into a useable form; - its retention, or storage, after being encoded; - and its recovery, or retrieval, when needed.
Retrieval: Getting information back out
Retrieval is the process of locating and recovering stored information from memory. Cues (prompts) are often relied on, to retrieve memories that have been stored in the brain.
Baddeley & Hitch's Working memory (STM)
STM = working memory, as we are consciously working with information, not just storing. This model describes the structure and function of working memory in terms of four components the phonological loop - specialised for verbal information the visuo-spatial sketchpad - specialised for visual and spatial information the central executive - manages the activities in the other two sub-systems and controls the whole system Episodic buffer - helps associate LTM info with working memory
Organisation of information in LTM
Semantic network theory suggests that Retrieval of information involves searching a particular 'region' of memory and then tracing associations for links, among memories (concepts) in that region, rather than a random search for information. A specific retrieval cue activates relevant stored memories which, in turn, activate other related memories to which they are linked. (Spreading Activation) Heirarchical structure - several nodes on the lowest level form part of one node at the next level up etc. The shorter the link, the stronger the association between nodes and the less time it takes to retrieve. Longer links between concepts indicate a weaker association and take longer to activate/retrieve. The more nodes that are activated, the quicker the information retrieval from LTM.
The Atkinson - Shiffrin multi-store model
Short-Term Memory Store (temporary working memory) manipulates information needed to perform everyday functions. holds all information that we are consciously aware of at any point in time receives information input from the sensory register and information retrieved for use from the long-term store limited capacity (∼ 7 items) and duration only for ∼ 30 seconds (unless rehearsed) Information that is not attended to or encoded is lost from memory permanently from sensory register and short-term store.
Time delay longer than duration of STM -
The serial position effect exists when testing recall immediately after learning When recall is delayed for 30 seconds, participants tend to forget the latter items and usually no recency effect is evident.
Long term memory Evidence to support the Multi-Store Model of Memory.
There are two types of evidence to support Atkinson and Shiffrin's proposal that information moves between the different memory stores: Free Recall studies: such as the serial position effect Studies of patients with brain damage.
Atkinson -Shiffrin multi-store model
Three stores of memory Sensory memory Short-term memory Long-term memory Information passes through 3 levels of memory as it is encoded, stored and retrieved Sensory - Short Term - Long Term
Atkinson - Shiffrin Encoding & Storage: Elaborative Rehearsal
To have the best chance of encoding information into LTM it is best to use a form of 'Elaborative Rehearsal'. The active process of linking new information in a meaningful way with information already stored in LTM, or with other new information, to aid in its storage and retrieval from LTM. The more elaborate/meaningful the various features of the concept with linkage to personal experience (self-referencing), the better the information is encoded and remembered for longer periods.
Sensory Memory - Iconic Memory George Sperling's Iconic Memory Studies
To test whether all letters were actually retained in iconic memory he conducted an additional study in which he sounded a tone just after a pattern of letters was flashed on the screen. On hearing: High tone - report letters from top row Medium tone - report letters from middle row Low tone - report letters from bottom row. Under this condition, participants had to select a line from the visual image they held in iconic memory, resulting in 75% accuracy after seeing a pattern of letters flashed on the screen. Results suggest that an image of all the letters (whole pattern) had been momentarily stored in iconic memory after the pattern left the screen. By delaying the tone for longer and longer intervals, Sperling was able to determine how quickly images in iconic memory fade.
Sensory Memory - Iconic Memory George Sperling's Iconic Memory Studies
Used a tachistoscope, to briefly present participants with set of 12 letters arranged in a pattern. Sperling projected the sets of letters on a screen for 1/20th of a second. Participants had to verbally report as many of the letters as they could recall. Most could only recall 4-5 letters in each set. Sperling believed that all letters in each set were seen because they had been initially registered in some way and should therefore all be available for a brief time. But because the image disappeared so quickly, only a few letters could be named before they were lost from iconic memory.
4. Working Memory: Episodic buffer
a sub-system that enables the different components of working memory to interact with LTM. Helps retrieve information from LTM to associate with information in working memory, and to select and encode information into LTM limited - capacity, temporary storage system, holding ∼4 chunks of information capable of holding information in any form (auditory phonological loop or visual-spatial) under control of central executive directly linked to but separate from LTM with own storage system able to pull together information from working memory and LTM to combine into episodes provides temporary working space where information can be processed and reordered in an organised and meaningful way
