Memory: Encoding, Storage, and Retrieval

• Systematic exploration of memory started with Hermann Ebbinghaus in 1885
• Frederick Bartlett suggested memory is an active constructive process in 1932

Memory Definition

• The cognitive system stores and retrieves information
• Memory retains and recalls info over time based on the task
• It receives sensory info, puts it in usable form, organizes it, and retrieves it from storage

Stages of Memory

• Encoding: Info is converted into a form that can be entered into memory
  • The first stage refers to a process by which information is recorded and registered for the first time so that it becomes usable by the memory system
  • External stimuli generate neural impulses
  • Incoming information is received, meaning is derived, and then it is represented for processing
• Storage: Retains information in memory
  • Information encoded must be stored for later use
  • Stores information held over time
• Retrieval: Stored information is located
  • Information can be used when one can recover it from memory
  • It brings stored information to awareness for cognitive tasks like problem-solving or decision-making
• Memory failure can occur at the stage of encoding, storage or retrieval

Systems of Storing Information

• Sensory Memory: Retains sensory input for brief periods
  • It is a temporary storage for sensory information
  • It holds information briefly in sensory channels
  • Most information held is lost or decays
  • Attended information is passed to short-term memory (STM) for processing
  • Iconic/visual images are stored for less than a second
  • Auditory sensory register holds information for 4-5 seconds as echoic memory
• Short-Term Memory (STM): Retains a small amount of information briefly
  • Holds information for about 30 seconds or less
  • Information from sensory memory is attended to and recognized and is passed to STM for 20-30 seconds
  • Rehearsal i.e. selective attention processes information in STM
  • Selective attention is the ability to focus on some aspects while ignoring others
• Long-Term Memory (LTM): Retains large amounts of information over time
  • It can remember events from hours ago to many years
  • Factual information is stored, like the capital, the president, and book information
  • Information enters through maintenance rehearsal or elaborative rehearsal
    • Maintenance rehearsal is repetition
    • Elaborative rehearsal processes information that links it to existing memory
  • Long-term memory storage has no limit and the capacity is unlimited
  • Information is there for good and instead we have trouble retrieving what has been stored. In other words, the information is still there but we cannot get to it because it has not been stored in an organized manner or because we are not searching in an organized way.

Important Terms

• Iconic Image:
  • This is where information held briefly in sensory channels themselves exists
  • The storage function of sensory channels can be known as the sensory register
  • Visual sensory register holds information for about 1 second
  • Auditory register holds information longer (4-5 seconds)
  • Holds 11-16 items before decaying
  • Visual sensory storage seems to be in the form of a faint image. The visual input’s copy or likeness is the iconic image
  • An iconic image persists in the visual sensory register for a second before gradually decaying
• Free Recall:
  • A memory retrieval process where individuals are asked to remember information without any specific cues or prompts
  • Participants study a list of items per trial and then are prompted to recall the items in any order
  • Typically lasts a few minutes and can involve spoken or written recall
  • The standard test involves the recall period starting immediately after the final list item; immediate free recall (IFR)
  • In delayed free recall (DFR), there is a short distraction period between the final list item and the start of the recall period
• Serial Position Effects:
  • The role of serial position in free recall.
  • States that the greater accuracy of recall of words or other information early and late in a list of information, than of words or information in the middle of the list
• Primacy and Recency Effects:
  • The serial position effect has better recall at the beginning of the list
  • The better recall at the end of the list contributes to the serial position effect

Episodic Memory

• Memory for factual information at a specific time
• It holds the information acquired at a specific time and place
• It allows one to go back in time and remember specific thoughts or experiences in the past
• Common type of memory studied and researched
• Relates to episodes and events
• Consists of personal events or experiences with one’s life

Semantic Memory

• A memory that stores general, abstract knowledge about the world
• This includes information you cannot remember acquiring at a specific time and place
• It holds information of a more general nature
• Includes the meaning of words, the properties of objects, typical events in everyday life, and the countless facts we all learn during our school years
• Information is organized through concepts i.e. mental categories
• Concepts are similar to one another

Concepts in Semantic Memory

• Meaning reflects its links or associations with other, adjoining concepts in semantic networks
• Meaning derives from prototypes which are abstract, idealized representation
• Any concept represented in memory is not in terms of an overall average (prototype) but with exemplars which is an example of the category that the individual can readily bring to mind

Procedural Memory

• Retains information that cannot be readily expressed verbally
• It is also called implicit memory
• Stores the information for doing or performing things without any conscious awareness about particular experience or learning
• There is no need for conscious control or attention to perform if the actions blueprint is stored in procedural memory
• Priming effect may facilitate recognizing a stimulus on a later occasion
• The priming effect refers to the difference between remembering and knowing
• Knowing is the familiarity with a stimulus even when you can't remember it explicitly, remembering means being able to report an event.

Working Memory

• Holds information being processed at the moment
• It is formerly called short-term memory
• It is the workbench of consciousness
• Holds and processes information being used
• As a storage system, it can hold about seven discrete items
• Each "item" can contain pieces of information that are grouped together into meaningful units; they are described as chunks
• Through chunking, it can hold a large amount of information, even though it can retain only seven to nine separate items at once

Processing in Working Memory (Alan Baddeley's Theory)

• A phonological loop: Processes information relating to the sounds of words
• A visuospatial sketchpad: Processes visual and spatial information e.g. appearance of objects, color, shape, and location
• A central executive: Supervises and coordinates the other two components
  • The central executive act as an interpreter for both visual and auditory information in STM
• Episodic Buffer - acts as a backup store, and communicates with long-term memory

Processing Memory - Information Processing Approach: The Stage Model

• (Atkinson and Shiffrin, 1968)
• Memory has three stages/tasks i.e. encoding, storage, and retrieval

Systems of Memory

• Sensory Memory: Retains representations of sensory input briefly
• Short Term Memory: Retains small amount of information briefly
• Long Term Memory: Retains large amounts of information

Atkinson and Shiffrin Model

• Moving information from one system to another involves active control processes that determine which information is retained
• Information enters short-term memory from sensory memory when it becomes the focus of attention
• In contrast, information in short-term memory enters long-term storage through elaborative rehearsal - thinking about its meaning and relating it to other information in long-term memory
• The study of human memory is firmly linked to information processing

Parallel Distributed Processing (PDP) Model

• Parallel (more than one process at a time)
• Distributed Processing (Processing occurring in a number of different locations)
• Proponents: J.L. McClelland & Rumelhart
• It assumes information is placed by different activation patterns
• These activations propagate among units
• Positive connections increase activation, negative decrease

PDP Model Principles

• The representation of information is distributed (not local)
• Memory and knowledge for specific things are stored in the connections between units
• Learning can occur with gradual changes in connection strength by experience

Forgetting

• Apparent loss of information already encoded and stored in long-term memory
• It is not simply a function of how much time has elapsed but rather what happens during that period
• Trace Decay: States that STM can only hold information between 0-18 seconds unless rehearsed
  • Explanation of forgetting in short-term memory assumes that memories leave a physical trace in the brain
  • Forgetting occurs because of the automatic decay or fading of the memory trace which focuses on time and duration
• Interference: Forgetting things with the interference
  • Effects previous learnings that we retained with more recent memory can work both backward and forward
  • Negative inhibiting effect
• Proactive Interference: It occurs when past information interferes with learning new information.
  • Old learnings retained in memory disrupts what we acquire
• Retroactive Interference: It occurs when new stimuli learning interferes with previously formed memories.
  • New learnings work backward to impair the retention of the previously learned material.
• Retrieval Failure:
  • Information is in long-term memory but cannot be accessed because the retrieval cues are not present
  • Cues can be external (environment) or internal (state)
  • Information is more likely retrieved if appropriate cues are present
  • Information is readily retrieved if cues at encoding are present at retrieval
  • Information about surroundings and the physical or psychological state is stored simultaneously at the learning stage
  • Reinstating state or context makes recall easier while retrieval failure occurs when appropriate cues are absent.
• Amnesia:
  • Amnesia refers to loss of memory from illness, injury, drug abuse, or other causes.
  • Disturbs or loses memory than everyday forgetting or absent-mindedness
• Amnesia may result from:
  • Organic or neurological causes (damage to the brain through physical injury, neurological disease or the use of certain drugs)
  • Functional or psychogenic causes (psychological factors, such as mental disorder, post-traumatic stress or psychological defense mechanisms)
• Types of amnesia:
  • Anterograde amnesia: The patient cannot remember new information; data does not transfer successfully from the conscious short-term memory into permanent long-term memory
  • Retrograde amnesia: The patient cannot remember events that occurred before the trauma but remembers things that happened normally after it - Person's pre-existing memories are lost beyond forgetfulness

Dementia

• A chronic or persistent disorder of mental processes caused by brain disease or injury
• It is characterized by memory disorders, personality changes, and impaired reasoning
• Progressive deterioration of thinking ability and memory as the brain becomes damaged essentially
• Memory loss is so severe it interferes with daily functions

Some common symptoms of dementia:

• Loss of memory
• Communication and language problems
• Inability to focus and pay attention
• Incorrect reasoning and judgment
• Visual perception is hampered Alzheimer's Disease counts for 50-75% of dementia Vascular dementia accounting 20% by blood clot or hemorrhage cutting off the brain's blood supply by stoke. Other types of dementia includes Lewy body dementia, frontotemporal dementia, Huntington's and Creutzfeldt-Jakob.

Alzheimer's Disease is a progressive, degenerative, and ultimately fatal brain disease caused by the loss of cell-to-cell connections in the brain and is the most common form of dementia also. Also referred to as senile dementia.

Some symptoms include repetitive statements and questions, forgetting, misplacing, and getting lost The causes are amyloid plaques (abnormal deposits of protein) and imbalances in acetylcholine. Treatment includes medication, support provided by healthcare workers that provide quality-of-life care.

Improving Memory

• Attention concentrating energies improves memory, understanding leads to little forgetting and more storage.
• Mnemonics:
  • It aids information retention, relies on linking or association of remember material with well known images of words, E.g. VIBGYOR
  • Acronym: a word from the first letters or grouped letters in a name or phrase - VIBGYOR for rainbow colors
• The Acrostic Method:
  • Used to remember a word or procedure by creating a sentence from the first letter of the word - treble staff EGBDF = Every Good Boy Does Fine
• Chunking: Is simply breaking down what you’re memorizing into smaller, or “chunks” for easier, organizing and efficiency
• 5 is the magic number for digit numbers
• Imagery:
  • Relates a particular image with a word
• The Method of Loci:
  • Memory pegs are the parts of the image of a scene.
• Peg systems: Links a digit to an object that resembles it, it hangs on the mental pegs