Memory Research Overview

Early Research into Memory

• Early researchers focused on the role of the brain in memory formation, but the exact changes were not fully understood.
• The concept of a "memory trace" or "engram" was introduced to describe hypothetical brain alterations related to stored memories.
• Major questions arose about how memories are localized in the brain and how neurons change during the formation of memory.
• Ivan Pavlov's research into conditioned responses influenced early memory theories.
• Pavlov's theory, while valuable, had limitations in fully explaining the brain's mechanisms involved in memory.

Imperfect Memories & False Memories

• Several factors contribute to false memories:
  • Misinformation effect
  • Preexisting schemas
  • Source confusion
  • Imagination inflation
  • Blending fact and fiction
  • Suggestion

Amnesia and Memory Processing

• Studying amnesia helps scientists understand brain regions involved in memory.
• Retrograde amnesia disrupts memory consolidation, affecting past memories.
• Anterograde amnesia disrupts the formation of new memories.
• The case of H.M. (Henry Molaison) is a well-known example of anterograde amnesia.
• Brenda Milner and Suzanne Corkin's research on H.M. highlighted the distinct brain regions involved in explicit and implicit memories.

Key Researchers and Their Findings

• Karl S. Lashley concluded that memories are distributed throughout the brain rather than localized.
• Richard F. Thompson demonstrated that memory for simple conditioned reflexes is localized in the brain.
• Eric Kandel's research revealed that new memory formation leads to structural and functional changes in neurons.
• Long-term potentiation, a lasting increase in synaptic strength, is crucial in memory consolidation.

Dementia and Alzheimer's Disease

• Dementia is a progressive decline in cognitive functions, including memory and reasoning.
• Alzheimer's disease (AD), the most common cause of dementia, is characterized by plaques and tangles in the brain.

Brain Structures and Memory

• Several brain structures are involved in memory processes:
  • The hippocampus plays a key part in memory consolidation.
  • The cerebellum is involved in motor memory and procedural learning.
  • The amygdala processes emotional memories.
  • The frontal lobes, including the prefrontal cortex, are crucial for working memory and decision-making.
  • The medial temporal lobes are important for declarative memory.

Neuronal Changes in Response to Sound

• Studies using Aplysia (sea snails) demonstrate how neurons change in response to repeated stimuli, leading to learned behaviors (gill withdrawal response).
• These changes include an increase in the number of neuron branches and synapses.
• This process, known as long-term potentiation, strengthens synaptic connections.
• Similar changes occur in other species, suggesting a common biological basis for learning and memory.

Source Confusion

• Source confusion arises when the origin of a memory is forgotten or misattributed.
• It can contribute to the misinformation effect, where false information provided after an event gets mixed into the original memory.
• Research highlights the high confidence people can have in false memories, often equaling their confidence in accurate memories.

Schemas and Memory Distortions

• Schemas, pre-existing mental frameworks, can shape and distort memories.
• They can lead to the inclusion of schema-consistent details, even if they were not present in the original experience.

Reliability of Memory

• Memories are not simply recordings, but rather reconstructions influenced by existing knowledge and understanding of the world.
• This reconstructive process can lead to inaccuracies and distortions in memory.

False Memory Example

• Doctored images can influence memory, causing people to incorporate false details into their recollections of real events.

Factors Contributing to False Memories (Table 6.3)

• Misinformation effect: incorrect information provided after an event can distort memory.
• Schema distortion: filling in missing details with schema-consistent information can lead to error.
• Source confusion: forgetting the true source of a memory can lead to inaccurate attribution.
• Imagination inflation: vividly imagining an event can increase confidence that it happened, even if it didn't.
• False familiarity: repeated imagining of an event can increase feelings of familiarity, leading to a false belief that it occurred.
• Blending fact and fiction: using vivid details to support a false memory can make it seem more believable.
• Suggestion: highly suggestive techniques like hypnosis can create false memories.

Eyewitness Misidentification: Convicting the Innocent

• Ronald Cotton's story underscores the fallibility of eyewitness testimony and the potential for misidentification.
• The case illustrates that eyewitness confidence can be a poor indicator of memory accuracy.

Schemas and Memory Distortions: The Influence of Existing Knowledge on What is Remembered

• Pre-existing knowledge in the form of schemas can significantly influence our memories.
• A study by Brewer and Treyens demonstrated that participants falsely remembered schema-consistent objects in a psychology professor's office, highlighting how schemas can contribute to memory distortions.

Forming False Memories

• False memories of events that never happened can be created through various techniques.
• Research on false memories has demonstrated that imagination can play a significant role in their formation.

The Lost-in-the-Mall Experiment

• Loftus and Pickrell's classic study used the "Lost-in-the-Mall" technique to induce false memories in participants.
• The study showed that participants could be led to believe they had experienced an event that never happened, even with vivid details.

Imagination Inflation

• Imagination inflation is the phenomenon where vividly imagining an event increases confidence that it actually occurred.
• Repeatedly imagining an event can contribute to its perceived familiarity and create false memories.

Memory: Key Processes and Stages

• Memory is a complex process that involves encoding, storage, and retrieval.
• The Stage Model of Memory describes three distinct memory stages: sensory memory, short-term memory, and long-term memory.

Sensory Memory

• Briefly stores sensory information from the environment.
• Each sensory modality has its own sensory memory.
• Visual sensory memory lasts for about half a second.

Short-Term Memory (STM)

• Temporarily stores information from sensory memory and retrieved information from long-term memory.
• Capacity is limited, typically to a few units of information.
• Maintenance rehearsal keeps information active in STM.
• Without active rehearsal, information fades from STM within 20 seconds.

Working Memory

• The active manipulation of information in STM.
• It's thought to consist of three components: phonological loop, visuospatial sketchpad, and central executive.

Long-Term Memory (LTM)

• Stores information potentially indefinitely.
• Elaborative rehearsal, focusing on the meaning of information, helps encode it into LTM.
• Information in LTM is organized and associated with related groups for easier retrieval.
• The semantic network model portrays LTM as a complex network of associations.

Retrieval

• The process of accessing information stored in LTM.
• Retrieval cues are hints or prompts that trigger recall.
• Retrieval cue failure occurs when adequate or missing retrieval cues make recall difficult, exemplified by the "tip-of-the-tongue" phenomenon.
• Recall, cued recall, and recognition are strategies for testing retrieval.

Types of Long-Term Memory

• Explicit memory (declarative memory): memory with conscious recall
  • Episodic memory: memories of personal events.
  • Semantic memory : memories of facts and general knowledge.
• Implicit memory (nondeclarative memory): memory without conscious recall
  • Procedural memory: memory for skills and actions.

Forgetting

• The inability to recall previously available information.
• Factors contributing to forgetting:
  • Encoding failure: information not properly encoded into LTM.
  • Retrieval cue failure: lack of adequate or missing retrieval cues.
  • Decay theory: information fades over time if not used.
  • Retroactive interference: new information interferes with recall of old information.
  • Proactive interference: older information interferes with recall of new information.
  • Suppression: conscious effort to avoid recalling specific information.
  • Repression: unconscious effort to avoid recalling specific information.

Hermann Ebbinghaus

• Identified a basic pattern of forgetting: rapid initial loss of information followed by a more stable retention of remaining information.

Explore the early research into memory, including concepts like the memory trace and the effects of conditioning as introduced by Ivan Pavlov. Learn about the factors that contribute to false memories and the implications of amnesia on memory processing and brain functions.