COGS 101B - Lecture 17 - Long-term Memory

{Serial position effect}: given a sequence of items, we’ll best recall {earliest and latest} items.

Q. Two “sub-effects” of the serial position effect
A. Primarcy effects and recency effects

Q. What is the primacy effect (w.r.t. the serial position effect)?
A. The first items in a presented sequence are best recalled

Q. Relate the serial position effect to long/short-term memory
A. Primacy effect is due to long-term memory encoding; recency effect is for words still in short-term memory

Q. What experiment demonstrates that the recency effect is due to info in short-term memory?
A. Count backwards from 30 after sequence; effect is eliminated

Capacity of semantic memory seems to depend on semantic coding: {proactive interference} is diminished when {switching between semantic categories} in a memory task. (Wickens et al, 1976)

Q. What part of his brain did HM have removed?
A. Hippocampus

Q. What primary symptom did HM suffer from?
A. Couldn’t transfer short-term memory to long-term.

Q. What’s a double dissociation in neuroscience?
A. A strong form of lesion evidence linking two functions to two brain regions: one reduces function A but not B; the other reduces B but not

Q. Two main types of long-term memory?
A. Explicit (conscious / declarative) and implicit (nondeclarative)

Q. In the context of long-term memory, “declarative” means:
A. You can articulate / verbalize the events / facts.

Q. What distinguishes implicit long-term memory from explicit long-term memory?
A. We’re not consciously aware of remembering implicit long-term memories.

Q. What’s an example of implicit long-term memory?
A. Riding a bike

Q. What evidence did patient HM provide that implicit and explicit long-term memory are different systems?
A. He could still learn skills over time (drawn a star), though he couldn’t remember explicit information.

Two key types of explicit long-term memory: {episodic} ({personal events}) and {semantic} ({facts, knowledge})

{Explicit} memory is also called {conscious} memory or {declarative} memory.

Evocative metaphor for {episodic memory}: {mental time travel}

Personal memories become less {episodic} and more {semantic} over time. (Petrican, 2010)

Last updated 2023-07-13.