Types of Long-Term Memory

The multi-store model described long-term memory (LTM) as a single, unitary store. However, research has shown that there are in fact different types of LTM, each storing different kinds of information and relying on different brain structures. Tulving (1972) proposed that LTM consists of three distinct types: episodic, semantic, and procedural memory.

flowchart TD
    A[Long-Term Memory] --> B[Explicit / Declarative]
    A --> C[Implicit / Non-declarative]
    B --> D["Episodic<br/>personal events<br/>time-stamped"]
    B --> E["Semantic<br/>facts and knowledge<br/>not time-stamped"]
    C --> F["Procedural<br/>skills and how-to<br/>automatic"]
    D --> G["Hippocampus +<br/>prefrontal cortex"]
    E --> H[Temporal lobe]
    F --> I["Cerebellum +<br/>motor cortex"]

---

Episodic Memory

Episodic memory stores personal experiences and events — your "autobiography." These are memories of specific things that have happened to you, stamped with the time and place they occurred.

Characteristics of Episodic Memory

• Memories are time-stamped — you can usually remember when the event happened
• They include contextual details — where you were, who was there, how you felt
• They are personal and unique to the individual
• They must be consciously recalled (you have to deliberately think about them)
• They are complex, involving multiple elements (people, places, objects, emotions)

Examples

• Remembering your first day at secondary school
• Recalling what you had for breakfast yesterday
• Remembering a family holiday

---

Semantic Memory

Semantic memory stores our knowledge of the world — facts, concepts, and meanings that are not tied to any particular personal experience.

Characteristics of Semantic Memory

• Not time-stamped — you usually cannot remember when or where you learned the information
• Shared knowledge — not personal or unique
• Includes facts, word meanings, and general knowledge
• Must be consciously recalled
• Can start as episodic memories that lose their personal context over time

Examples

• Knowing that London is the capital of England
• Understanding what the word "democracy" means
• Knowing that 2 + 2 = 4

---

Procedural Memory

Procedural memory stores knowledge of how to do things — motor skills and actions that have been learned through practice.

Characteristics of Procedural Memory

• Implicit (unconscious) — you do not need to consciously think about the steps involved
• Difficult to explain to someone else in words
• Acquired through practice and repetition
• Very resistant to forgetting
• Often involve motor skills and automatic responses

Examples

• Riding a bicycle
• Typing on a keyboard
• Playing a musical instrument
• Tying your shoelaces

---

Comparing the Three Types of LTM

Feature	Episodic	Semantic	Procedural
What is stored	Personal events and experiences	Facts and general knowledge	Skills and how to do things
Time-stamped?	Yes	No	No
Conscious recall?	Yes (explicit)	Yes (explicit)	No (implicit/automatic)
Example	Remembering your last birthday	Knowing Paris is in France	Knowing how to ride a bike
Ease of forgetting	Can be forgotten	Fairly stable	Very resistant to forgetting

---

Evidence for Different Types of LTM

Case Study: Clive Wearing

Clive Wearing is a musician who suffered brain damage from a viral infection (herpes encephalitis) that severely affected his hippocampus. As a result:

• His episodic memory was severely impaired — he could not form new episodic memories and had lost most of his past personal memories
• His semantic memory was partially intact — he retained some general knowledge
• His procedural memory was intact — he could still play the piano and conduct a choir, even though he had no memory of having learned to do so

This case strongly supports the idea that episodic, semantic, and procedural memory are separate systems in the brain, because damage can affect one type while leaving others intact.

Brain Imaging Studies

Research using brain scans (such as PET scans and fMRI) has shown that different types of LTM are associated with different brain regions:

Type of LTM	Brain Region
Episodic	Hippocampus, prefrontal cortex
Semantic	Temporal lobe (especially the neocortex)
Procedural	Cerebellum, basal ganglia, motor cortex

This provides biological evidence that the three types of LTM are distinct from each other.

---

Evaluation

Strengths

• Supported by case studies (e.g. Clive Wearing, HM) showing that different types of LTM can be affected independently
• Supported by brain imaging research showing different brain regions are involved
• Has practical applications — understanding different types of LTM helps in treating memory disorders
• Provides a more detailed and accurate picture of LTM than the MSM, which treated it as a single store

Weaknesses

• The distinction between episodic and semantic memory is not always clear — some memories have elements of both
• Most evidence comes from case studies of brain-damaged patients, which are difficult to generalise
• Brain imaging studies show correlation but do not prove causation — activation of a brain area during a task does not prove that area is solely responsible

Exam Tip: If asked to describe the types of LTM, always give a clear definition AND an example for each type. If asked to evaluate, use Clive Wearing as evidence that the types are separate, but note the weakness that case studies cannot be generalised.

---

Key Points

• Tulving (1972) proposed three types of LTM: episodic, semantic, and procedural.
• Episodic memory = personal events (time-stamped, conscious recall).
• Semantic memory = facts and knowledge (no time stamp, conscious recall).
• Procedural memory = skills and how-to knowledge (unconscious, automatic).
• Evidence from brain-damaged patients (e.g. Clive Wearing) supports the distinction.
• Brain imaging shows different brain regions are involved in each type.

---

Study case: The Clive Wearing case study

Aim: To document and understand the pattern of memory impairment following severe damage to the hippocampus and surrounding structures, and what this reveals about the organisation of long-term memory. Clive Wearing, a British musician and conductor, contracted herpes simplex encephalitis in 1985, which attacked his temporal lobes and left him with one of the most severe cases of amnesia ever documented.