Topic 2.3 Notes – Introduction to Memory

What Memory Is

Memory means learning that lasts over time. Psychologists usually break it into three processes:

• Encoding means getting information into memory in a usable form.
• Storage means keeping that information over time.
• Retrieval means bringing it back into awareness, or letting it affect what you do.

A common test trap is thinking failed retrieval means the memory was never there. It might have been stored but you couldn’t access it at that moment.

Memory is also an information-processing system, not a video camera. It selects, organizes, and reconstructs information.

The main frameworks here answer different questions:

• Types of memory ask what kind of memory is this?
• Multi-store model asks where does information go?
• Working memory model asks what does active memory do?
• Levels of processing asks why do some encodings last better?
• Long-term potentiation asks what brain change helps memory last?

Types of Memory

Explicit memory

Explicit memory is conscious, declarative memory. You can describe it to someone else.

It has two forms that students mix up a lot:

• Episodic memory
  Memory for personal events. It includes what happened, and often where and when.
  Example: remembering your last birthday party.

• Semantic memory
  Memory for facts, meanings, and general knowledge.
  Example: knowing what a diploma is or that water freezes at 0°C.

The key distinction is this. If you remember learning the fact, that is episodic. If you just know the fact, that is semantic.

Implicit memory

Implicit memory affects behavior without conscious recall. You often show it through performance.

• Procedural memory is memory for skills and habits.
  Examples: typing, riding a bike, playing a practiced song pattern.

Prospective memory

Prospective memory is memory for future intentions.

• remembering to take medicine later
• remembering to turn in an assignment tomorrow

This is different from episodic memory because it points forward, not backward.

One situation can use several memory types at once. Playing piano from habit uses procedural memory, knowing note names uses semantic memory, and remembering to perform tomorrow uses prospective memory.

The Multi-Store Model

The multi-store model describes memory as three interacting systems.

This basic flow diagram matches the model you'll see in many psych classes.

Multi-store model of memory

• Sensory memory holds incoming sensory info very briefly.
  • Iconic memory = visual sensory memory
  • Echoic memory = auditory sensory memory
    Echoic lasts a bit longer, which helps you make sense of speech.
• Short-term memory briefly holds limited information in active awareness. Without continued processing, much is lost quickly.
• Long-term memory stores knowledge, experiences, and skills more durably. It includes both explicit and implicit memories.

How information moves in the diagram:

• Attention moves info from sensory memory to short-term memory.
• Maintenance rehearsal keeps information active in short-term memory.
• Transfer moves it into long-term memory.
• Retrieval brings long-term memory back into active awareness.

Automatic and effortful processing

• Automatic processing happens with little conscious effort.
• Effortful processing requires attention, rehearsal, and mental work.

Effortful processing usually gives stronger encoding into long-term memory.

How Working Memory Works

Working memory is active, limited-capacity memory. It doesn’t just hold information. It works with it.

Baddeley and Hitch’s model breaks working memory into parts that handle different kinds of information and a control system that manages them.

Baddeley and Hitch working memory model

• Central executive directs attention, switches focus, and coordinates the system.
• Phonological loop temporarily holds and rehearses verbal or auditory information, like repeating a phone number.
• Visuospatial sketchpad temporarily holds and manipulates visual or spatial information, like picturing a route.

Important distinction. The phonological loop and visuospatial sketchpad are parts of working memory. They are not sensory memory, and they are not long-term memory.

Why Some Memories Last

Levels of processing

The levels of processing model says memory depends on how deeply you encode information.

Think of it as a shift from shallow processing of what something looks or sounds like to deeper processing of what it means.

• Structural processing focuses on appearance
  Example: uppercase letters or word length
• Phonemic processing focuses on sound
  Example: pronunciation or rhyming
• Semantic processing focuses on meaning and connections
  Example: using a word in a sentence

Semantic processing usually leads to the best retention. The reason is meaningful encoding, not just more time spent.

Long-term potentiation

Long-term potentiation (LTP) is a long-lasting strengthening of synaptic connections after repeated activation.

• often summed up as “neurons that fire together wire together”
• strongly linked to memory pathways like the hippocampus
• helps explain how experience creates lasting neural change

LTP supports memory. It is not the memory itself.