Topic 7 lecture slides- memory

Human Memory

• Quote by Beth Loftus: "Many people believe that memory works like a recording device. Memory works a little bit more like a Wikipedia page: You can go in there and change it but so can other people."

Understanding Memory

• Memory is the process of encoding, storing, and retrieving information.

• Memory is not static; it can change over time.

• We often fill in gaps in our memories, making us prone to error.

• Our brains actively process information to make sense of the world.

Foundations of Memory

Three Core Processes

• Encoding: Initial recording of information.

• Storage: Information saved for future use.

• Retrieval: Recovery of stored information.

Three-Stage Model of Memory

• There are three different types of memory with varying spans and durations:

  • Sensory Memory

  • Short-Term Memory (STM)

  • Long-Term Memory (LTM)

• Information must pass through all stages to be remembered.

Sensory Memory

• Brief storage of sensory events (sights, sounds, tastes).

• Each sensory modality has distinct memory storage:

  • Iconic Memory: Visual system; lasts < 1 sec.

  • Echoic Memory: Auditory; lasts 2-3 secs.

• High precision but transitory; unless transferred, info is lost.

Short-Term Memory (STM)

• Limited capacity: retains information for about 30 seconds.

• Typical capacity is 7 ± 2 items (magic number 7).

• information in STM is either discarded or stored in LTM.

Extending STM Capacity

• Chunking: Organizing large bodies of information into smaller, meaningful groups to extend STM span.

Rehearsal: STM to LTM

• Rehearsal: Repeating information enhances memory consolidation.

  • Maintenance Rehearsal: Repeating stimuli in the same form.

  • Elaborative Rehearsal: Organizing and linking information meaningfully, more effective for memory retention.

Working Memory

• Active, temporary storage for manipulating and rehearsing information.

• Contains a central executive processor for reasoning and decision-making.

Long-Term Memory (LTM)

• Continuous storage with no limit; may last decades or a lifetime.

• Distinction between anterograde and retrograde amnesia.

Recall and Recognition in Memory

• Primacy Effect: Recall of first stimuli in a list.

• Recency Effect: Recall of last stimuli in a list.

• Unique stimuli can enhance recall independent of their position.

Case Study: Henry Molaison (HM)

• Following his hippocampus removal for seizure treatment, he could not form new explicit memories.

• Improved in mirror tracing tasks despite lack of explicit memory.

• Demonstrates the distinction between explicit and implicit memory.

Long-Term Memory Types

• Declarative Memory: Involves conscious recollection.

  • Semantic Memory: General knowledge (e.g., knowing the prime minister).

  • Episodic Memory: Personal experiences (e.g., first kiss).

• Non-Declarative Memory: Memory affecting behavior without conscious recollection.

  • Procedural Memory: Skills and actions (e.g., riding a bike).

  • Priming: Activation of existing knowledge to facilitate new information recall.

Neuroscience of Memory

Key Structures

• Hippocampus: Critical for memory consolidation and encoding.

• Amygdala: Important for emotional memories.

Long-Term Potentiation

• Neural pathways become easier to activate as responses are learned: "neurons that fire together, wire together."

Why Do We Forget?

Encoding Failures

• Events may not be encoded if not attended to.

• Next-in-line Effect: Lack of recall for events directly preceding one's turn.

• Self-Reference Effect: Better memory for information related to oneself.

Factors Leading to Forgetting

• Retrieval Failure: Decay and interference.

• Retroactive Interference: New information disrupts previously learned information.

• Proactive Interference: Older information interferes with learning new information.

Amnesia Types

1. Anterograde Amnesia: Inability to remember new information after trauma.

2. Retrograde Amnesia: Loss of memory for events before trauma.

Memory Retrieval Processes

Types of Retrieval

1. Recall: Accessing information without prompts.

2. Recognition: Identifying learned information upon encountering it.

Tip-of-the-Tongue Phenomenon

• Occurs when retrieval fails despite feeling certain of knowing the information. Can sometimes be aided by related cues.

Levels of Processing Theory

• Depth of analysis when exposed to information affects memory retention.

  • Shallow Processing: Basic sensory aspects (e.g., memorizing terms).

  • Deep Processing: Meaning-based analysis related to prior knowledge.

Encoding Specificity

• Better recall if retrieval conditions match encoding conditions.

  • Context-Dependent Learning: Performance improved in familiar environments.

  • State-Dependent Learning: Memory performance affected by emotional state (e.g., sobriety).

Flashbulb Memory

• Vivid memories of significant emotional events, easier to recall but not always accurate.

  • Examples include historical events (e.g., 9/11).

Memory is Reconstructive

• Over time, we forget and reconstruct memories influenced by cognitive frameworks (schemas) and post-event information.

• Important implications for legal settings, particularly eyewitness testimony.

Schemas & Scripts

• Schemas: Mental structures that organize knowledge and help fill memory gaps.

• Memory can be distorted to conform to schemas, affecting recall accuracy (e.g., robbery script study).

Memories are Suggestible

• Suggestibility can create false memories due to external misinformation.

• Important in contexts like eyewitness testimony, impacting legal outcomes.

The Misinformation Effect

• Post-event information can distort or alter original memories (e.g., Loftus experiments).

False Memories Studies

• Experimentation demonstrates how individuals can be led to recall non-existent events.

  • E.g., Loftus study where a significant portion of subjects accepted implanted memories.

Mandela Effect

• Collective misremembering of specific facts or events (e.g., brands like 'Fruit Loops').

Laboratory Induction of False Memories

• Studies have successfully implanted various false childhood memories, demonstrating memory's malleability.

Memory Hacker Study

• Controversial study asserting that a high percentage of participants had false crime memories implanted.

Eyewitness Misidentification

• Leading cause of wrongful convictions; significant focus in DNA exoneration cases, where eyewitness misidentifications were prevalent.

Line-up Procedures

• Witnesses are asked to identify suspects from line-ups containing distractors.