Memory and Information Processing

• Memory is the set of processes to record and retrieve experiences.

Memory as Information Processing

• Encoding translates information into a neural code.
• Storage retains information over time.
• Retrieval pulls information back out.

Three-Stage Model of Memory

• Memory components are separate but interacting.
• Components include: sensory memory, working (short-term) memory, and long-term memory.
• Temporary & long lasting.
• Works but doesn't correspond to specific brain structures.

Three-Stage Model

• Sensory input goes to sensory memory, then working/short term memory, then long-term memory.
• Sensory memory uses sensory registers.
• Working/short term memory uses encoding and rehearsal.
• Long term memory uses encoding and retrieval.
• Information moves through stages of memory as it gets encoded, stored, and retrieved.
• Unattended information is lost from sensory memory; unrehearsed information is lost from short-term memory, and some information may be lost from long-term memory over time.

Sensory Memory

• It briefly holds sensory information
• Iconic stores are for visual information and last fractions of a second.
• Echoic stores are for auditory information and last for about 2 seconds; a partial trace can last longer.
• Sensory registers are initial information processors.
• When a grid of letters flashes on screen for only 1/20th of a second, it is difficult to recall individual letters.
• If prompted to remember a particular row immediately after the grid appears, research participants will do so with high accuracy (Sperling, 1960).

Short Term / Working Memory

• It temporarily holds a limited amount of what we are conscious of
• Working memory codes and 'works on' information

Representation of Information in Short-Term Memory

• Mental representations/memory codes occurs in images(visual), sounds (phonological), meaning (semantic), action (motor)
• Doesn't correspond to the form of the original stimulus
• Errors are often phonetic
• Words or letter that sound alike are confused (e.g., B or V; man or mad).

Capacity and Duration of Short-Term Memory

• The magical number is 7 ± 2 (Miller, 1956).
• It has a capacity of 5-9 meaningful items.
• The digit span task tests this.

Increasing Short-Term Memory

• Chunking involves combining individual items into larger units of meaning.
• This is effective when the 'chunk' is meaningful.
• For example, MRC CHIR NSERC have meaning for grant researchers, and NHL CFL NBA may be meaningful for sports fans.

'Shelf-life' of Short Term/Working Memory

• There's a 'Shelf-life' of 20 seconds for information.
• Quickly lost unless one actively 'does something' with it.
• A 1959 experiment showed how quickly short-term memory fades without rehearsal.
• Research was highly accurate when tested a few seconds after exposure to each string of letters on a test for memory of three-letter strings.
• If the test had a delay of another 15 seconds, people barely recalled the strings at all (Peterson & Peterson, 1959).

Extending Duration of Shot-Term Memory

• Extend by maintenance rehearsal: Simple repetition
• Extend by elaborative rehearsal: Focus on meaning and is more effective

Short Term Memory at 'Work'

• It functions as a 'Mental workspace'
• Information is actively processed and supports problem solving and planning
• Used for solving problems such as adding 2 numbers or creating a visual 'map' of a route.

Short Term Memory Components

• Phonological loop: auditory storage
• Visual-spatial sketchpad: store of mental images and spatial information
• Central executive: directs attention, recall from LTM, integration of input
• Involves the prefrontal cortex

Long-Term Memory

• Described as a library of durable stored memories with unlimited storage capacity.
• Can endure for a lifetime.
• In contrast to both sensory and short-term memory, long-term memory has no known capacity limits.
• People can recall items even if they haven't thought of them for years.
• Researchers have found that even 50 years after graduation, people can accurately recognize about 90% of their high school classmates from yearbook photographs.

Serial Position Effect

• Serial position effect is the distinction between short-term and long-term memory
• Presented with unrelated words, then recall as many as you can
• Two components: primacy and recency effect.
• U-shaped pattern as a function of position in series.
• There is superior recall of early & most recent words.
• Primacy effect indicates information transferred to long-term memory.
• Primacy effect is diminished if words presented at a higher rate.
• Recency effect is when information is still in short-term memory.
• Recency effect is diminished if time delay before recall.
• Known as a “Double Dissociation".

Encoding

• Encoding is more effective into LTM = greater likelihood of retrieval
• Effortful Processing: Intentional and conscious (Studying)
• Automatic Processing: Unintentional and requiring minimal attention (Recalling what you did yesterday)

Maintenance & Elaborative Rehearsal

• Maintenance: Rote repetition of information that is not an optimal method
• Elaborative: Focuses on information's meaning, organizing, understanding, applying to one's life, relating to already learned concepts, and using imagery.

Encoding: Levels of Processing

• A depth of processing increases recall
• POTATO - is word in capitals (structural)
• Horse - does it rhyme with course? (phonological)
• TABLE - does it fit in sentence ‘The man peeled the __' (semantic)

Encoding: Organization & Imagery

• Organizing information in a meaningful way enhances memory.
• A scheme serves as a cue for retrieving information.

Hierarchies & Chunking

• Chunking involves combining items into larger units of meaning.
• Hierarchy means memory is enhanced by associations.
• Hierarchy enhances understanding of how elements are related.
• Organizing words into conceptual groups and relating them to one another—such as in a hierarchy—makes it easier to reconstruct the items from memory later (Bower et al., 1969).
• Keeping track of the 17 items in this example can be facilitated by remembering the hierarchical groupings they fall under.

Prior Knowledge Shapes Encoding

• Schemas: A 'mental framework', that is an organized pattern of thought.
• Create perceptual sets that help to organize and interpret information.
• Development of expert knowledge: Process of developing schemas
• E.g., chess players, coaches, musicians, & psychology students!
• Experts rely on perceiving 'meaning' in a pattern.

Memory as a Network

• Associative Networks: Network of associated ideas and concepts
• Each concept represented by 'node'
• Nodes tightly clustered for highly related concepts
• Activation of one concept activates other concepts = Priming
• Priming is to retrieve a specific memory from the web of associations, one must first activate one of the strands that leads to it.

Visual Imagery

• Dual coding theory: Memory enhanced if use both verbal and visual codes
• More difficult with some stimuli
• Easier with concrete objects than with abstract concepts

Method of loci

• Uses imaginary physical environment and placement of images to help information retrieval
• E.g., associating image with word 'jealousy'.

Types of Long Term Memory

• All call upon long-term information, but each is different
• Include: knowledge of your birthday, how to use the word 'justice' in a sentence, and demonstration of throwing a ball
• Some types are unique to you and others are general to all of us
• Some require physical movement.
• Can be declarative or procedural.

Declarative Memory

• It can be verbalized, with two subcategories: episodic and semantic.
• Includes personal experiences ('episodes' of your life).
• Also includes general factual knowledge.

Procedural Memory

• It is non-declarative memory that is reflected in skills & actions in addition to some classically conditioned responses. Explicit & Implicit Memory
• Explicit Memory: involves conscious or intentional memory retrieval
• Implicit Memory: Memory influences behavior, requires no conscious awareness and includes priming tasks.

Henry Molaison (“H.M.”)

• In 1953, the removal of H.M.'s hippocampus at age 27 ended his seizures and his ability to form new explicit memories.
• H.M. could learn new skills, procedures, locations of objects, and games, but had no memory of the lessons or the instructors.
• H.M. also retained memories from before the surgery.
• H.M. was unable to report that he has played this game after leaning and playing Tower of Hanoi.

Amnesia

• Retrograde Amnesia: Memory loss for events before amnesia
• Anterograde Amnesia: Memory loss for events after amnesia
• Alzheimer's Disease: Severe retrograde and anterograde amnesia

Infantile Amnesia

• Memory loss for early childhood experiences and typically for events before ages of 3-4.
• Caused by an immature brain and encoding failures.

Accuracy of Children's Memories

• A Critical issue = Suggestive Questioning
• It can distort children's memories
• Younger children more susceptible to misleading & suggestive questions
• Observers could not tell false from true reports by children
• Children are not intentionally lying and believe memory is accurate
• Non-suggestive interviewing is crucial

Forgetting

• Retrospective Memory is for past events
• Prospective Memory remembers to perform activity in future.
• Elderly have some difficulty with time-signaled tasks.

Misinformation

• It is distortion of memory by misleading post-event information.
• Can affect eyewitness testimony.
• Can occur because of source confusion.

Constructive Processes

• One cannot use rewind button to activate memories
• Memory is a constructive (or reconstructive) process
• Piece together bits of information in ways that intuitively “make sense"
• Often highly inaccurate
• Schemas can distort memories
• Confabulation

Biology of Memory

• The search for engram
• Engram is defined as the physical trace stored in brain when memory formed.
• Engram is thought to not exist.
• Memory is stored throughout brain.

Studying Memory in the Brain

• Three basic approaches: Human Lesion Studies, and Brain-Imaging Studies also Nonhuman Animal Lesion Studies
• Human Lesion Studies: Study memory loss due to brain damage
• Nonhuman Animal Lesion Studies: Deliberate damage to brain regions.

Function of the Hippocampus

• Encoding station and converts short-term memories to long-term.
• Binding process in the brain for: Where something happened, What the scene or people looked like, Sounds heard, Meaning of events

Cerebral cortex

• Encodes information from sensory registers and stores semantic information.
• Prefrontal cortex: Involved in functions of working memory.
• Deep processing increased brain activity in specific regions of left prefrontal cortex.
• Thalamus: Role is unclear, Damage results in extensive anterograde & retrograde amnesia
• Amygdala: Emotional aspects of memory
• Cerebellum: Procedural memory

Nervous system form memory?

• Synaptic Change using Kandel's work with Aplysia
• Structural changes resulted in greater synaptic transmission
• Long-Term Potentiation = enduring increase in synaptic strength and Synaptic connections activated more easily.
• Long-term potentiation (LTP): Process whereby communication across the synapse between neurons strengthens the connection, making further communication easier
• NMDA receptor: Receptor site on the hippocampus that influences the flow of information between neurons by controlling the initiation of LTP
• Glutamate and excitation Improving Memory
• Three broad strategies: External aids, General strategies, Mnemonic devices.

Improving Memory: General Strategies

• Elaborative rehearsal: Understand it
• Link to other information and make it meaningful
• Organize information: Use textbooks as organized with chapters and outlines, or build own scaffold of organization.

Additional Memory Help

• Overlearn: Continued rehearsal
• Distribute learning over time: Cramming the night before is not good!
• Minimize interference