Memory systems What kinds of things do we know? Is all memory the same? Types of memory systems Semantic and episodic memory.

Types of things we know

Is there just one memory system? Are all of these types of memory the same? How do you learn a new skill? –How long does it take? –How do you study? –How long does the memory last –Are you conscious of retrieving the skill? How about learning a new fact? How about learning about an event you experience?

Maybe there isn’t just one LTM We will discuss many kinds of memory systems –Procedural vs. declarative memory –Episodic vs. semantic memory –Implicit vs. explicit memory These distinctions overlap somewhat

Questions to answer What kind of information is stored in that memory? How do you get information into the system? –How long does it take? How do you get memory out of the system? Are you conscious of the experience of retrieval? What brain regions are involved in that system?

Semantic and episodic memory One of the earliest distinctions to be made Semantic memory –Memory for facts, categories, and types of events Who is the President of the United States? What type of furniture do you sit on? What is this person doing?

Episodic memory Memory for things that happened to you. –What happened at a birthday party? –What did you eat for breakfast? –What did you see at the football game?

Structure of semantic memory Semantic memory is organized around content –The hierarchical model (Collins & Quillian)

Structure of semantic memory Semantic memory is organized around content –The hierarchical model (Collins & Quillian) Nodes

Structure of semantic memory Semantic memory is organized around content –The hierarchical model (Collins & Quillian) Nodes Links

Structure of semantic memory Semantic memory is organized around content –The hierarchical model (Collins & Quillian) Nodes Links Nodes and Links have Labels

Why does this makes sense? Why should we think semantic memory looks like this? Allows efficient storage of properties –Do rhinos have horns? –Do rhinos breathe? –Are rhinos made of molecules? We would not want to store every property with every concept. It would be useful to be able to derive some information.

Lexical Decision tasks Seeing one word prepares us to see related words.

Episodic Memory Some things are not facts. A chair The time the dog sat in the chair

Episodic Memory Some things are not facts. A chair The time the dog sat in the chair A fact An episode of (someone’s) life

How is episodic memory structured? Tulving Organized chronologically –Think about what you did last weekend. Memory for sensations Truth is determined by personal belief Often requires deliberate access Admissable as eyewitness testimony –Only experts may testify about semantic memory

Studies of episodic memory Most memory studies tap episodic memory Recall and recognition –Do you remember this item from a particular list you studied? –Do you recognize this item as one you saw on a particular occasion?

Distinguishing types of memory Jacoby and Dallas (1981) Find a way to dissociate the types of memory –An episodic test that is influenced by a manipulation –A semantic test that is not Return to depth of processing –Episodic task: Recognition –Semantic task: Identify word from brief presentation

Summary There are many types of memory Memory systems have different characteristics Semantic memory –Memory for facts, organized around content Episodic memory –Memory for events, temporal organization