Chapter 8

MEMORY

Overview of Memory

  • Memory encompasses several questions:

    • How do we process and store information?

    • Are there different types of memory?

    • How do we retrieve memories?

    • Why do we forget?

  • Photographs can evoke memories and revive past experiences. (Credit: modification of work by Cory Zanker)

HOW MEMORY FUNCTIONS

  • Memory functions as an information processing system akin to a computer, involving a series of processes for encoding, storing, and retrieving information across different times.

    1. Encoding: Input of information into the memory system.

    2. Storage: Retention of encoded information.

    3. Retrieval: Accessing and bringing information back into awareness.

ENCODING

  • Encoding occurs when the brain receives environmental information and involves:

    • Labeling/Coding: Identification of new information.

    • Organizing: Structuring it with similar information.

    • Connecting: Linking new concepts to existing knowledge.

Types of Processing

  1. Automatic Processing:

    • Involves encoding of time, space, frequency, and meaning of words.

    • Typically occurs without conscious awareness (e.g., remembering when you last studied).

  2. Effortful Processing:

    • Requires time and effort to encode information (e.g., learning new skills like driving).

    • Initial learning demands full concentration, but can become automatic over time.

TYPES OF ENCODING

  1. Semantic Encoding:

    • Encoding of words and meanings.

    • Most effective encoding form that facilitates recall by attaching meaning.

  2. Visual Encoding:

    • Encoding of images; concrete words create mental images easier to recall than abstract words.

  3. Acoustic Encoding:

    • Encoding of sounds.

    • Self-Reference Effect: Superior recall for information related to oneself compared to less personally relevant material.

STORAGE: BADDELEY & HITCH MODEL

  • Proposed by Baddeley and Hitch:

    • Short-term memory operates in various forms depending on the info type received.

    • Memory storage is likened to accessing different computer files:

    1. Visuospatial Sketchpad

    2. Episodic Buffer

    3. Phonological Loop

    • A central executive supervises information flow between the systems. (Credit: mercercognitivepsychology)

STORAGE: A-S MODEL

  • Atkinson-Shiffrin Model of Memory:

    • Information is processed in three distinct stages to reach long-term memory, modeling memory processing after computer information processing.

SENSORY MEMORY

  • Sensory Memory: Short-term storage of brief sensory events (e.g., sights, sounds, tastes).

    • Duration: Up to a few seconds.

    • First step in processing stimuli; discarded if unimportant, but can transition to short-term memory if valuable.

THE STROOP EFFECT

  • Stroop Effect: Difficulty in naming a color when mismatched with the word (e.g., "blue" printed in red). This phenomenon is rooted in sensory memory study.

SHORT-TERM MEMORY (STM)

  • Short-Term Memory/Working Memory: Temporary storage system for incoming sensory information.

    • Duration: Approximately 20 seconds.

    • Capacity: Generally around 7 items (±2), identified by George Miller.

  • Information in STM may be discarded or consolidated into long-term memory.

  • Memory Consolidation: Transition from STM to long-term memory, often aided by Rehearsal, the conscious repetition of information.

LONG-TERM MEMORY (LTM)

  • Long-Term Memory: Ongoing storage of information without known limits, resembling a computer's hard drive.

Components of Long-Term Memory

  1. Explicit Memory (Declarative)

    • Consciously recalled facts and events.

    • Semantic Memory: Knowledge about concepts and language (e.g., knowing who the president is).

    • Episodic Memory: Personal experiences, including specific event details (e.g., remembering a birthday).

    • Hyperthymesia: A condition where individuals like actress Marilu Henner have exceptional autobiographical memory.

  2. Implicit Memory

    • Unconscious memories formed through behaviors.

    • Procedural Memory: How-to knowledge on performing tasks (e.g., riding a bike).

    • Involves responses formed through emotional conditioning (e.g., fear of spiders without recalling why).

RETRIEVAL

  • Retrieval: The process of recovering information from memory storage back into conscious awareness, crucial for everyday tasks.

Methods of Retrieval

  1. Recall: Accessing information independently of cues; relevant for essay tests.

  2. Recognition: Identifying previously learned information upon encountering it again; used in multiple-choice tests.

  3. Relearning: Accelerated re-acquisition of knowledge previously learned (e.g., relearning Spanish after a long break).

DISCOVERING PARTS OF THE BRAIN INVOLVED IN MEMORY

  • Karl Lashley: Investigated the concept of an engram, a neuron group representing a memory, through brain lesion studies in animals.

    • Equipotentiality Hypothesis: If one brain region associated with memory is damaged, another can assume that function.

  • Eric Kandel: Examined synaptic processes controlling information flow through neural circuits for memory retention.

PARTS OF THE BRAIN INVOLVED IN MEMORY

  1. Amygdala:

    • Emotional information processing and memory encoding, particularly for fear-related memories, influenced by stress hormones.

  2. Hippocampus:

    • Related to explicit and spatial memory and has a vital role in memory consolidation.

    • Damage disrupts new declarative memory creation (e.g., Patient H.M.'s loss of new semantic and episodic memory).

  3. Cerebellum:

    • Responsible for procedural memory processing and classical conditioning responses.

  4. Prefrontal Cortex:

    • Activation during semantic tasks; encoding linked to left-sided prefrontal activity, retrieval linked to right-sided activity.

NEUROTRANSMITTERS IN MEMORY

  • Key role of neurotransmitter communication for new memory development.

  • Process: Repeated neuronal activity boosts neurotransmitter levels in synapses, enhancing connections.

Neurotransmitters involved in memory include:

  • Epinephrine

  • Dopamine

  • Serotonin

  • Glutamate

  • Acetylcholine

Arousal Theory

  • Strong emotions can forge stronger memories, while weaker emotions yield less impactful memories.

  • Illustrated by Flashbulb Memories: vivid recollections of significant emotional events.

FLASH BULB MEMORY

  • Flashbulb Memory: Retention of extraordinary events associated with intense emotion.

    • Examples include historical events like assassinations, moon landings, and significant national tragedies.

    • Formation influenced by cultural context and personal significance, with personal involvement heightening memorability.

AMNESIA

  • Amnesia: Loss of long-term memory stemming from disease, trauma, or psychological factors.

Types of Amnesia

  1. Anterograde Amnesia:

    • Inability to form new memories after a traumatic event; typically linked to hippocampus damage.

  2. Retrograde Amnesia:

    • Partial or total memory loss for events leading up to trauma.

MEMORY CONSTRUCTION & RECONSTRUCTION

  • Memory retrieval often alters and modifies memories, leading to erroneous recollections.

Suggestibility

  • Suggestibility can result in false memory creation, influenced by external misinformation, significantly affecting eyewitness accounts.

EYEWITNESS MISIDENTIFICATION

  • Research indicates misidentification can occur from leading police procedures, with wrongful convictions often traced to erroneous eyewitness memory.

THE MISINFORMATION EFFECT

  • Misinformation Effect Paradigm: Post-exposure to incorrect details may distort memories of the original event.

    • Study found that the wording of questions influenced speed estimates of car accidents.

REPRESSED & RECOVERED MEMORIES

  • Controversial subject regarding the repression of traumatic events and potential recall, such as via hypnosis or guided imagery.

    • False Memory Syndrome: Recall of inaccurate autobiographical memories.

  • Loftus challenges the validity of repressed memories, raising questions about memory accuracy.

FORGETTING

  • Forgetting: Loss of information from long-term memory.

Encoding Failure

  • Occurs when memory is not effectively stored due to inadequate attention or effort.

MEMORY ERRORS: SCHACTER’S 7 SINS OF MEMORY

Forgetting Types

  1. Transience: Memory accessibility decreases over time, leading to storage decay.

  2. Absentmindedness: Memory lapses due to inattention.

  3. Blocking: Temporary information access issues (e.g., tip-of-the-tongue experiences).

Distortion Types

  1. Misattribution: Confusion about the memory source.

  2. Suggestibility: Creation of false memories through external suggestions.

  3. Bias: Memories influenced by current beliefs.

Intrusion Types

  1. Persistence: Unwanted memories that are difficult to forget.

TRANSIENCE/STORAGE DECAY

  • Information fades over time when unused.

  • Ebbinghaus Forgetting Curve shows memory decay rates:

    • 50% retained after 20 minutes.

    • 30% retained after 24 hours.

BIAS

  • Memory can be distorted by emotions and viewpoints:

    • Stereotypical Bias: Associations made with racial and gender stereotypes.

    • Egocentric Bias: Enhancing memories of one’s past actions for self-advantage.

    • Hindsight Bias: The belief that one could have predicted an outcome after the fact.

PERSISTENCE

  • Many veterans voluntarily or involuntarily recall traumatic memories.

INTERFERENCE

  • Forgetting may stem from difficulty in retrieving information due to interference, which can be proactive or retroactive.

WAYS TO ENHANCE MEMORY

  • Utilizing specific techniques can improve memory retention:

    1. Rehearsal: Conscious repetition of information.

    2. Chunking: Organizing info into manageable units.

    3. Elaborative Rehearsal: Relating new info to existing knowledge.

    4. Mnemonic Devices: Memory aids for encoding, like acronyms or visual tricks.

MNEMONIC DEVICES

  • Knuckle mnemonic for remembering the number of days in each month:

    • Protruding knuckles represent months with 31 days; shorter months fit in between.

HOW TO STUDY EFFECTIVELY

  • Effective study strategies include:

    1. Use elaborative rehearsal.

    2. Apply self-reference effect.

    3. Practice to counteract storage decay.

    4. Regular rehearsal.

    5. Minimize distractions during study.

    6. Engage in regular aerobic exercise for brain health.

    7. Ensure sufficient sleep for memory consolidation.

    8. Incorporate mnemonic devices into study habits.

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