Types of Long-Term Memory

• Key Features of Long-Term Memory (LTM):

  • LTM is theoretically unlimited in capacity and duration.
  • Different types of LTM rely on different brain regions.
  • Some LTM types require conscious effort (declarative), while others are automatic (non-declarative).
• Episodic Memory:

  • Episodic memory refers to memory for personal experiences and events that have occurred in an individual’s life.
  • These memories are time-stamped, meaning they include details about when and where the event happened.
  • Episodic memory is declarative, meaning it requires conscious effort to recall.
• Key Features:Episodic Memory

  • Time-stamped – Memories are associated with a specific time and place.
  • Personal – Based on an individual’s unique experiences.
  • Includes contextual details – E.g., emotions felt at the time.

  Eg:

  • Your last holiday
  • Your first day at school
  • A wedding you attended
• Episodic Memory:Neuroscientific Evidence

  • Episodic memory is heavily linked to the hippocampus and prefrontal cortex.

  Tulving (1989) – PET Scans:

  • Found that episodic memories activate the right prefrontal cortex during retrieval.
• Supporting Research:Episodic Memory

  Case Study: HM (Henry Molaison):

  • After undergoing surgery to remove his hippocampus, HM lost the ability to form new episodic memories but could still learn new skills.
  • This suggests that episodic memory is separate from procedural memory.
• Semantic Memory:

  • Semantic memory is memory for general knowledge and facts about the world.
  • Unlike episodic memory, it is not time-stamped, meaning we do not remember when we acquired the knowledge.
  • Semantic memory is declarative, requiring conscious recall.
• Key Features:Semantic Memory

  • Not time-stamped – Facts and concepts are stored independently of when they were learned.
  • General knowledge – Shared among individuals rather than being unique to each person.
  • Continuously expanding – New knowledge can be acquired over time.

  Eg:

  • Knowing that the earth orbits the sun
  • Understanding that dogs are mammals
  • Knowing that 2+2=4
• Semantic Memory:Neuroscientific Evidence

  • Semantic memory is linked to the left prefrontal cortex.

  Tulving (1989) – PET Scans:

  • Found that semantic memory retrieval activates the left prefrontal cortex.
• Supporting Research:Semantic Memory

  Case Study: Clive Wearing

  • Despite severe amnesia, Clive Wearing retained his semantic knowledge (e.g., understanding music theory) but lost his episodic memory.
  • This supports the idea that semantic and episodic memory are separate stores.
• Procedural Memory:

  • Procedural memory is the memory for motor skills and actions that have been learned through repetition and practice.
  • It is non-declarative, meaning it can be recalled without conscious effort.
• Key Features:Procedural Memory

  • Not time-stamped – We don’t remember when we first learned a skill.
  • Automatic recall – Accessed without deliberate effort.
  • Highly resistant to forgetting – Procedural skills are well-practiced and rarely fade.

  Eg:

  • Riding a bike.
  • Typing on a keyboard.
  • Driving a car.
• Procedural Memory:Neuroscientific Evidence

  • Procedural memory is linked to the cerebellum and basal ganglia, rather than the hippocampus.
• Supporting Memory:Procedural Memory

  Case Study: Clive Wearing

  • Despite severe amnesia, Clive Wearing could still play the piano perfectly but could not remember learning it.
  • This supports the distinction between procedural and declarative memory.
• Declarative Memory:

  Memory that requires conscious recall; includes episodic and semantic memory.
• Non-Declarative Memory:

  Memory that does not require conscious effort to recall; includes procedural memory.
• Time-Stamped:

  A characteristic of episodic memory, meaning memories are linked to specific times and contexts in a person’s life.
• Implicit Memory (Non-Declarative Memory):

  • A type of long-term memory that is unconscious and automatic, meaning it does not require deliberate effort to recall.
  • It includes skills, habits, and conditioned responses, such as riding a bike or tying shoelaces.
• Explicit Memory (Declarative Memory):

  • A type of long-term memory that requires conscious effort to recall.
  • It includes factual knowledge and personal experiences.
  • It is divided into episodic memory (events) and semantic memory (facts and concepts).