MEMORY

ATKINSON-SHIFFRIN MULTI-STORE MODEL OF MEMORY

BRAIN REGIONS INVOLVED IN STORAGE OF LTM

EFFECTS OF BRAIN TRAUMA ON MEMORY

RELIABILITY OF MEMORY

ABILITY AND INABILITY TO REMEMBER

Memory
The processing, storage and retrieval of information acquired through learning.

3 Main Processes of Memory

  1. Encoding
    Conversion of information into a usable form so that it can be neurologically represented ('placed') and stored in memory.
  2. Storage
    Retention of the encoded information over time
  3. Retrieval
    Recovery of stored information and bringing it into conscious awareness for use when needed

Represents memory as consisting of three separate stores called sensory memory, short-term memory and long-term memory

Sensory Memory
Function: The entry point of memory where new information is stored for a very brief period.
Duration: Momentary, up to 10 seconds occasionally
Capacity: Vast, potentially unlimited

  • If the sensory info is attended to = transferred to STM
  • If the sensory info is not attended to = lost forever
  • Not consciously aware of info in sensory memory
  • Stores impressions long enough for each impression to slightly overlap the next, so our world is perceived as continuous, not disjointed

Iconic Memory
Used to describe visual sensory information. Retain visual images in their original sensory form in iconic memory for about 1/3 of a second.

Echoic Memory
Used to describe auditory sensory memory. Retain info in echoic memory for 3-4 seconds.

Short-Term (Working) Memory
Function: Information received into short-term memory is processed (encoded) and stored for a brief period, unless a conscious effort is made to keep it there longer. A conscious effort is continually rehearsing the information, called maintenance rehearsal.
Duration: 18-20 seconds
Capacity: 5-9 items (when STM is full new items can only enter through displacement - pushing one item out through displacement)

STM as Working Memory
As our working memory, STM enables us to actively work on and manipulate information while we undertake our everyday tasks. Information from sensory memory is processed in working memory and information is retrieved from LTM to be used and manipulated in working memory. Once the required task has been completed the info stored there is no longer required, and is either transferred to LTM or discarded.

Long-Term Memory
Function: Where knowledge and memory are held
Duration: Potentially unlimited
Capacity: Possibly permanent

Explicit Memory
Involves memory that occurs when information can be consciously or intentionally retrieved and stated. We are aware of these memories

Episodic Memory
The memory of personally experienced events

Semantic Memory
The memory of facts and knowledge about the world

Implicit Memory
Involves memory that does not require conscious or intentional retrieval. You are not aware you are remembering, nor are you necessarily trying to remember something you were trying to do.

Procedural Memory
The memory of motor skills and actions that have been learned previously

Classically Conditioned Memory
Conditioned responses to conditioned stimuli acquired through classical conditioning.

Amygdala
Involved in the formation of a wide range of emotional memories. Has a role in classically conditioned fear responses. Attaches emotional significance to LTMs through presence of noradrenaline. Consolidates implicit memories.

Cerebral Cortex
Stores long-term explicit semantic and episodic memories where they were first processed. When required, these separate parts are gathered together and reconstructed as a single, integrated memory for retrieval into our conscious awareness

Cerebellum
Encodes and temporarily stores implicit procedural memories. Crucial for motor learning and movement, but these memories are stored in the cerebral cortex. Stores implicit memories, especially classically conditioned simple reflexes and contributes to navigation and spatial learning.

Hippocampus
Turns short-term memories into long-term memories. Crucial in the consolidation of new semantic and episodic memories so they are neurologically stable and long-lasting. Temporarily stores memories during the consolidation process before storage in the cerebral cortex. Important for spatial memory. Believed to have a part in linking all components of memory together. Not directly involved in the formation of implicit memories.

Retrieval Methods

Recall
Involves reproducing information stored in memory

Serial Recall
Reproducing information in the order in which it was learned

Cued Recall
The use of specific prompts to aid retrieval and therefore reproduction of the information.

Free Recall
Reproducing as much information as possible in no particular order without a cue, in no specific order

Relearning
Involves learning information again that has been previously learned (and stored in LTM). If information is learned more quickly the second time, it is assumed that some info must have been saved in LTM the first time.

Recognition
Involved identifying (recognising), the original, learnt information. The presence of the correct information acts as a cue for its retrieval from memory.

Sensitivity of Retrieval Methods
A sensitive measure of retention is more likely to detect information that has been learned and stored in memory at some time in the past than a measure that is not very sensitive.
Recall = least sensitive measure of retention
Recognition = more sensitive than recall but less sensitive than relearning
Relearning = most sensitive measure of retention

Reconstruction
Generally involves combining stored information with other available information to form what is believed to be a more coherent, complete or accurate memory. Reconstructed memory can contain errors and distortions. When we form a LTM, we actively encode and organise the elements throughout different areas of the brain, which are linked together with neural networks or pathways. When we later access this memory, we do not retrieve the exact memory, but the encoded elements and we actively reconstruct the memory. When we do this, various factors lead to errors, or what we think we remember. With repeated retrieval, our memory undergoes further distortion, and can be hard to distinguish between initial and further encoding.

Loftus
Loftus found that eyewitness memory is not always accurate because witness reconstruct their memories, which can be manipulated by leading questions that contain misleading information. A leading question can influence memory as we integrate information from a leading question. Over time, information from 2 sources - their experience and false information - is integrated into one false memory
Leading Question
Has content or is phrased in a way as to suggest what answer is desired. They contain a presupposition - information that should or must be true for the question to make sense.

Anterograde Amnesia
Amnesia is used to refer to loss of memory that is inconsistent with ordinary forgetting. If brain trauma causes loss of memory for information after the trauma occurs, it is called anterograde amnesia. They have little difficulty retrieving long-term memories but cannot form new memories so nothing can move from short to long-term memory. Associated with damage to the hippocampus.

Brain Surgery - Damage or Removal of Parts of the Brain

Hippocampus
Disrupts ability to consolidate STM to LTM. Can cause anterograde amnesia. Does not seem to affect procedural memories but explicit memories are affected.

Amygdala
Emotional portion of memories are affected and conditioned fear responses are affected

Cerebral Cortex
Serious memory impairments to explicit memories

Cerebellum
Affects memories of classically conditioned fear responses

Neurodegenerative Diseases
A disorder characterised by the progressive decline in the structure, activity and function of brain tissue. Essentially neurons within the brain tissue become damaged or deteriorate and lose function.

Alzheimer's Disease
A type of dementia characterised by the gradual widespread degeneration of brain neurons, progressively causing memory decline, deterioration of cognitive and social skills and personality changes. Short term memory loss is the first to go, followed by long- memory. In the initial stage, deficits are evident in a number of areas but the person can function. Later they may forget, events, words, directions, knowledge and everyday skills. In a brain with Alzheimer's there is a high level of abnormal structures that interfere with neural communication within and between neurons, and therefore cognitive functioning. These abnormalities involve plaques and tangles.

Plaques
Fragments of the protein beta amyloid, and in a healthy brain that protein is broken down and eliminated. In a brain with Alzheimer's the fragments accumulate over time, and form insoluble clumps outside and around neurons, therefore inhibiting neural communication.

Tangles
Neurofibrillary tangles look like twisted fibres, and inhibit transport of essential substances through the neurons, this is thought to kill the neurons.

Forgetting - Retrieval Cues
Any stimulus that assists the process of locating and recovering information stored in memory. Acts as a clue or hint that guides the search and recovery of information. According to the retrieval failure theory, we sometimes forget because we lack or fail to use the right cues.

State Dependent Cues
Internal cues that are related to a specific experience, that are associated with an individual's internal physiological or psychological state at the time.

Context Dependent Cues
Environmental cues in the specific context (situation) where a memory was formed that act as retrieval cues.

Remembering - Rehearsal
Information can be kept in STM for longer than 18-20 seconds through rehearsal. Rehearsal is the process of consciously manipulating information to keep it in STM, to transfer it to LTM, or to aid storage and retrieval.

Maintenance Rehearsal
Involves repeating the information being remembered over and over again so that it can be retained (or maintained) in STM. Can be vocal or sub-vocal (in your head).

Elaborative Rehearsal
The process of linking new information in a meaningful way with other new info or info already stored in LTM to aid its storage and later retrieval from LTM

Serial Position Effect
Finding that free recall is better for items at the end and beginning of the list. Recall tends to be best for items at the end, than the beginning, and worst for items around the middle.
Primacy Effect
Describes superior recall of items at the beginning of a list
Recency Effect
Describes superior recall of items at the end of a list

Why The Serial Position Effect Occurs

  • If recall occurs immediately after the list is learned, the last few items are remembered best because they are still in STM
  • The first few items in a list are remembered well because they received more attention and rehearsal than other items and are therefore transferred into LTM
  • Items around the middle of a list are presented to late to be adequately rehearsed and transferred into LTM and too early to be held in STM without rehearsal, so they are more likely to beforgotten