PSYA01 CH.9

9-1 What Is Memory?

  • Definition of Memory: Memory is the ability to retain knowledge.

  • Importance of Memory in Life: The case of patient Molaison highlights how memory is crucial to our daily functioning.

  • Adaptive Advantage: Memory allows organisms to respond quickly to challenges and adapt to their environment.

9-1a Memory Provides an Adaptive Advantage

  • Evolutionary Perspective:

    • Memory is seen as a "neural machine" that uses past information to coordinate behavior in the present (Klein, Cosmides, & Tooby, 2002, p. 308).

    • Memory aids survival by allowing past experiences to inform current behavior, reducing reaction time in life-threatening situations.

  • Energy Costs of Memory:

    • Memory formation requires energy, and for memory systems to persist in evolution, benefits must outweigh costs.

    • Example: In fruit flies (Drosophila), memory formation about classically conditioned associations (e.g., odors and shocks) leads to early mortality; flies that learned to avoid shocks died four hours sooner than those that did not (Mery & Kawecki, 2005).

    • Despite costs, memory is vital for almost all animals, showcasing its survival benefits.

9-1b Memory Metaphors

  • Uses of Metaphors: Metaphors help us understand complex phenomena like memory.

  • Historical Metaphors:

    • Plato and Aristotle compared memory to a wax tablet where impressions form and fade (Hamilton, 1961; Yates, 1966).

  • Modern Analogies:

    • The computer metaphor from the 1950s-60s describes cognitive processes as input, storage, and retrieval.

    • Main difference: Computers store exact data; brains reconstruct memories from bits, allowing for flexibility but also inaccuracies.

  • Memory Processing: Memory processes involve flowing information and can be influenced by both bottom-up (stimulus-driven) and top-down (expectation-driven) processes.

9-1c The Memory Process: Encoding, Storage, and Retrieval

  • Three Steps of Memory:

    1. Encoding: Acquiring information and transferring it into memory.

      • Involves translating sensory input into neural signals (e.g., action potentials).

    2. Storage: Retaining encoded information.

      • Duration can vary: sensory memories (fractions of a second), short-term (up to 30 seconds), long-term (indefinitely).

    3. Retrieval: Accessing stored information, which may fail due to stress or interference.

  • Common Issues: Encoding failure occurs when attention is lacking (e.g., daydreaming).

  • Differences in Human vs. Computer Memory:

    • Computers store exact data reliably; human memory is reconstructive, leading to potential errors.

9-2 The Multistore Model of Memory

  • Atkinson and Shiffrin Model: A fundamental model of memory processes categorizing memory into distinct stages.

    • Memory not transferred is lost.

9-2a Sensory Memory

  • Function: Sensory memory holds extensive data for very brief durations (1 second or less).

  • Types of Codes:

    • Iconic Memory: Visual codes for images.

    • Echoic Memory: Acoustic codes for sounds; they last longer than visual codes.

  • Demonstration: George Sperling's experiments showed iconic memory's brief duration through letter recall tests.

9-2b Short-Term Memory (STM)

  • Function: STM processes limited information from sensory memory with a maximum duration of about 30 seconds without rehearsal.

  • Capacity: According to Miller's theory (“the magical number 7 ± 2”), STM can hold 5-9 items but is reduced to about four items according to contemporary research.

9-2c Long-Term Memory

  • Definition: Infinite capacity for storage and potential for indefinite duration.

  • Rehearsal:

    • Maintenance Rehearsal: Simple repetition of information;

    • Elaborative Rehearsal: Linking new info to existing knowledge for more effective coding (levels of processing theory).

9-3 Types and Characteristics of Long-Term Memory

  • Two Major Types:

    • Declarative (Explicit) Memory:

    • Semantic Memory: General knowledge and facts.

    • Episodic Memory: Personal experiences and events, organized chronologically.

    • Nondeclarative (Implicit) Memory: Harder to verbalize; includes procedural memories (skills) and priming effects.

9-3a Declarative and Autobiographical Memories

  • Semantic Memory Details: General knowledge organized by category.

  • Episodic vs. Autobiographical Memory:

    • Combines semantic and personal dimensions, thus impacting subjective experiences.

9-3b Nondeclarative Memories

  • Procedural Memories: Skills and tasks that are often hard to verbalize but easy to carry out (e.g., riding a bike).

9-4 Connectionist Theories of Memory

  • Connectionism: Sees memory as a network model where concepts lead to others, activated by association (spreading activation model).

9-5 How Do We Retrieve Memories?

  • Importance of Retrieval Cues: Cues can help access stored information more efficiently.

  • Recall vs. Recognition:

    • Recall tasks are typically more challenging than recognition tasks.

9-5a Short-Term Memory Retrieval

  • Sternberg's Task: Demonstrated that retrieval from STM does not occur simultaneously but item by item, affecting reaction time.

9-5b Retrieval from Long-Term Memory

  • Cues: Effective cues enhance retrieval and personal relevance amplifies memory retention.

9-5c Emotional Memory Retrieval

  • Influence of Emotions: Emotional arousal enhances memory for significant events through mechanisms such as stress and hormones.

9-6 Why Do We Forget?

  • Definition of Forgetting: A decrease in the ability to remember previously formed memories, distinct from not having formed a memory at all.

9-6a Decay Theory

  • Decay: Memories fade over time without practice or retrieval.

9-6b Interference Theory

  • Interference: New and old memories compete, leading to forgetting.

    • Types:

    • Proactive Interference: Older memories impede new learning.

    • Retroactive Interference: New learning impacts older memories.

9-6c Motivation and Memory

  • Motivated Forgetting: To avoid unpleasant memories, individuals may fail to retrieve certain information.

9-7 The Biology of Memory

  • Neurological Basis: Memory involves synaptic consolidation and protein changes in neurons.

9-7a Synaptic Changes

  • Long-Term Potentiation (LTP): Increases synaptic efficiency underlies memory formation.

9-7b Memory and the Brain Regions

  • Hippocampus: Essential for forming new declarative memories; damage results in anterograde amnesia.

9-7c Memory Biochemistry

  • Neurotransmitters: Acetylcholine, glutamate, and GABA play roles in memory processes and functioning.

9-8 Improving Memory

  • Effective Strategies: Include distributed practice, self-testing, physical exercise, and using mnemonic devices.

    • Cramming is ineffective compared to distributed study strategies.

    • Recitation: Explaining material improves understanding and memory retention.

    • Method of Loci: Visual association assists in remembering ordered lists.