24/4/24 Learning and Memory Task 2
TASK 2 – LONG TERM MEMORY AND
CONSOLIDATION
CHAPTER 7: EPISODIC AND SEMANTIC MEMORY
INTRODUCTION – PATIENT HM
• Patient HM documented that the formation of new fact and event memories depends on distinct
brain regions, separate from the brain regions that mediate other cognitive functions and other kinds
of memory
• Seizures; in the medial temporal lobes
• Surgical removal of medial temporal lobe from the hemisphere where the seizures originate
eliminate the epilepsy. HM had his medial temporal lobes removed bilaterally
• After surgery, developed amnesia à lost the ability to form new memories for facts and events
• Personality unchanged
• Could no longer follow the plot of a television show, because the commercials would interrupt his
memory of the story line
• As long as he paid attention to the task, he could perform well, as soon as his attention diverged the
information vanished
• Living proof that the ability to form new fact and event memories depends on the medial
temporal lobes but that many kinds of memory (and cognitive functions) do not
7.1 BEHAVIOURAL PROCESSES
Episodic memory = memory for specific events in your life; includes information about the spatial and
temporal context: where and when an event occurred
Semantic memory = memories for facts and general knowledge about the world, as well as for general
personal information such as your own name & fav food
» Semantic memory is not tagged in time and place
* Episodic memory is what we REMEMBER, semantic memory is what we KNOW
,24/4/24 Learning and Memory Task 2
FEATURES OF EPISODIC AND SEMANTIC MEMORIES
• Both episodic and semantic memories can be communicated flexibly
• Skill memories are not as easy to communicate flexibly in the way episodic and semantic memories
are
• Both are consciously accessible; if someone asks question about a fact, you either know the answer
or recall the event
Declarative memory = a broad class of memories, both semantic and episodic, that can typically be
verbalized (‘declared’) or explicitly communicated in some other way
» Reflect the fact that it is easy to verbalize (‘declare’) or otherwise communicate your knowledge
Non-declarative memory = a broad class of memory that includes skill memory and other types of
learning that do not fall under the heading of episodic or semantic memory and that are not always
consciously accessible or easy to verbalize
» Skill learning, operant conditioning, classical conditioning
Explicit memory = a category of memory that includes semantic memory and episodic memory and
consists of memories of which the person is aware: you KNOW you know the information
Implicit memory = memory that occurs without the learner’s awareness
» HM had no conscious memories of the training sessions and no knowledge of his new skills
» Demonstrate that conscious awareness is not absolutely necessary for implicit memories to
form
Episodic memories are always acquired in a single exposure (event itself)
• Semantic memories can be acquired in a single exposure too, especially if info is interesting or
important. BUT ordinary semantic info generally needs a few additional exposures before being fully
acquired
,24/4/24 Learning and Memory Task 2
• While repeated exposures to a single fact strengthen semantic memory for that fact, it weakens
episodic memory for any of these events
HM could not acquire new episodic and semantic memories, but could learn new skills (learning mirror-
reversed text)
» However, when asked about these new skills, HM reported having no conscious memories of the
training sessions and no knowledge of the new skill à the learning was implicit
There are 3 views on the relationship between episodic and semantic memories:
1. Episodic memory grows out of semantic memory (by Endel Tulving) : an organism needs to have a
certain amount of semantic information before episodic memories can be built on that framework
(ex. If you do not know what graduation is, you cannot have episodic memory for any graduation)
2. Semantic memory represents information that is encountered so many times that the actual learning
episodes are blurred and only the semantic ‘fact’ content remains
3. Episodic and semantic memory are fundamentally interdependent: each can affect the other
o Episodic memories will be stronger/last longer when there is a rich background of semantic
information to help us recognize and encode aspects of the event
o Semantic memories will be stronger/last longer when we have a distinct episodic memory of
the context in which we encountered the info
à it may be useful not to classify memories as being either strictly episodic or semantic but
recognize many of our memories include both
Patient K.C. shows evidence for the distinction between semantic and episodic memory
» Sustained brain injuries in traffic incident: extensive damage to left frontal-parietal and right parietal-
occipital cerebral cortex + reduced volume of hippocampus and shrinkage of parahippocampal
cortex
» KC can no longer retrieve any personal memory of his past, although his general knowledge remains
good
» KC has difficulty acquiring new semantic knowledge, but he can acquire some, it trials are spaced
out to prevent interference among items. However, he CANNOT acquire new episodic knowledge
» Most likely the anterior neocortical damage is responsible for the loss of episodic memory, because
other patients with hippocampal damage do not show this symptom
o Consistent with studies in healthy subjects showing activity in anterior regions of the cortex
during recall of episodic memories, and increases in posterior regions during recall of
semantic materials
, 24/4/24 Learning and Memory Task 2
WHAT DISTINGUISHES EPISODIC FROM SEMANTIC MEMORY?
• Episodic memories concern specific events that occurred at a particular place and time (you must
remember when and where those events occurred)
• Semantic memories involve factual information: you need not remember where and when, only the
fact itself
• Episodic memory is always autobiographical, the event must have happened to you
• Semantic memory can be personal (remembering your mom’s fav flavor of ice cream) or general
factual information (president of the US) : you do not need to remember where or how you acquired
this info
• Episodic memory is acquired in a single exposure: the event itself
• Semantic memories can be acquired in a single exposure too, BUT ordinary semantic info generally
needs a few additional exposures before being fully acquired
o Repeated exposures to a single fact strengthen semantic memory for that fact
• Repeated exposure to very similar events may weaken episodic memory for any of those events
(parking lot confusion with where you parked days before
ASSESSING EPISODIC AND SEMANTIC MEMORIES IN ANIMALS
Semantic memory can be easily assessed in humans by asking them questions. This is not the case for
animals
Rat experiment: radial arm maze à task that is used to assess semantic memory in rats
• A maze with a central area from which several arms branch off like the spokes of a wheel. The top of
the maze is open so a rat placed in the maze can see out and use landmarks of the room (ex.
Placement of posters)
• ‘goal arm’ and ‘start arm’, rat learns where the food is located after practice and when it is placed
in the start arm it will run straight to the goal arm
• Rat ‘knows’ where the food is when trained and can still find food from a new start arm (using a new
route)
Episodic memories in animals are harder to assess and there is controversy about whether animals can form
episodic memories at all
• Some researchers think that animals cannot form episodic memories because an episodic memory
requires re-experiencing the event in memory, which requires a conscious sense of self, which has
not been (according to them) demonstrated in nonhumans
• Endel Tulving argued that episodic memory requires ‘mental time travel’ (reexperiencing of the
event in memory) which requires a conscious sense of self, as well as subjective sense of time
passing, so nonhumans did not demonstrate
• BUT other researchers argue there IS evidence that animals can form episodic like memories
• Study: a gorilla named King was taught how to refer to various fruits and humans by using cards with
drawings that represented the fruits and humans
TASK 2 – LONG TERM MEMORY AND
CONSOLIDATION
CHAPTER 7: EPISODIC AND SEMANTIC MEMORY
INTRODUCTION – PATIENT HM
• Patient HM documented that the formation of new fact and event memories depends on distinct
brain regions, separate from the brain regions that mediate other cognitive functions and other kinds
of memory
• Seizures; in the medial temporal lobes
• Surgical removal of medial temporal lobe from the hemisphere where the seizures originate
eliminate the epilepsy. HM had his medial temporal lobes removed bilaterally
• After surgery, developed amnesia à lost the ability to form new memories for facts and events
• Personality unchanged
• Could no longer follow the plot of a television show, because the commercials would interrupt his
memory of the story line
• As long as he paid attention to the task, he could perform well, as soon as his attention diverged the
information vanished
• Living proof that the ability to form new fact and event memories depends on the medial
temporal lobes but that many kinds of memory (and cognitive functions) do not
7.1 BEHAVIOURAL PROCESSES
Episodic memory = memory for specific events in your life; includes information about the spatial and
temporal context: where and when an event occurred
Semantic memory = memories for facts and general knowledge about the world, as well as for general
personal information such as your own name & fav food
» Semantic memory is not tagged in time and place
* Episodic memory is what we REMEMBER, semantic memory is what we KNOW
,24/4/24 Learning and Memory Task 2
FEATURES OF EPISODIC AND SEMANTIC MEMORIES
• Both episodic and semantic memories can be communicated flexibly
• Skill memories are not as easy to communicate flexibly in the way episodic and semantic memories
are
• Both are consciously accessible; if someone asks question about a fact, you either know the answer
or recall the event
Declarative memory = a broad class of memories, both semantic and episodic, that can typically be
verbalized (‘declared’) or explicitly communicated in some other way
» Reflect the fact that it is easy to verbalize (‘declare’) or otherwise communicate your knowledge
Non-declarative memory = a broad class of memory that includes skill memory and other types of
learning that do not fall under the heading of episodic or semantic memory and that are not always
consciously accessible or easy to verbalize
» Skill learning, operant conditioning, classical conditioning
Explicit memory = a category of memory that includes semantic memory and episodic memory and
consists of memories of which the person is aware: you KNOW you know the information
Implicit memory = memory that occurs without the learner’s awareness
» HM had no conscious memories of the training sessions and no knowledge of his new skills
» Demonstrate that conscious awareness is not absolutely necessary for implicit memories to
form
Episodic memories are always acquired in a single exposure (event itself)
• Semantic memories can be acquired in a single exposure too, especially if info is interesting or
important. BUT ordinary semantic info generally needs a few additional exposures before being fully
acquired
,24/4/24 Learning and Memory Task 2
• While repeated exposures to a single fact strengthen semantic memory for that fact, it weakens
episodic memory for any of these events
HM could not acquire new episodic and semantic memories, but could learn new skills (learning mirror-
reversed text)
» However, when asked about these new skills, HM reported having no conscious memories of the
training sessions and no knowledge of the new skill à the learning was implicit
There are 3 views on the relationship between episodic and semantic memories:
1. Episodic memory grows out of semantic memory (by Endel Tulving) : an organism needs to have a
certain amount of semantic information before episodic memories can be built on that framework
(ex. If you do not know what graduation is, you cannot have episodic memory for any graduation)
2. Semantic memory represents information that is encountered so many times that the actual learning
episodes are blurred and only the semantic ‘fact’ content remains
3. Episodic and semantic memory are fundamentally interdependent: each can affect the other
o Episodic memories will be stronger/last longer when there is a rich background of semantic
information to help us recognize and encode aspects of the event
o Semantic memories will be stronger/last longer when we have a distinct episodic memory of
the context in which we encountered the info
à it may be useful not to classify memories as being either strictly episodic or semantic but
recognize many of our memories include both
Patient K.C. shows evidence for the distinction between semantic and episodic memory
» Sustained brain injuries in traffic incident: extensive damage to left frontal-parietal and right parietal-
occipital cerebral cortex + reduced volume of hippocampus and shrinkage of parahippocampal
cortex
» KC can no longer retrieve any personal memory of his past, although his general knowledge remains
good
» KC has difficulty acquiring new semantic knowledge, but he can acquire some, it trials are spaced
out to prevent interference among items. However, he CANNOT acquire new episodic knowledge
» Most likely the anterior neocortical damage is responsible for the loss of episodic memory, because
other patients with hippocampal damage do not show this symptom
o Consistent with studies in healthy subjects showing activity in anterior regions of the cortex
during recall of episodic memories, and increases in posterior regions during recall of
semantic materials
, 24/4/24 Learning and Memory Task 2
WHAT DISTINGUISHES EPISODIC FROM SEMANTIC MEMORY?
• Episodic memories concern specific events that occurred at a particular place and time (you must
remember when and where those events occurred)
• Semantic memories involve factual information: you need not remember where and when, only the
fact itself
• Episodic memory is always autobiographical, the event must have happened to you
• Semantic memory can be personal (remembering your mom’s fav flavor of ice cream) or general
factual information (president of the US) : you do not need to remember where or how you acquired
this info
• Episodic memory is acquired in a single exposure: the event itself
• Semantic memories can be acquired in a single exposure too, BUT ordinary semantic info generally
needs a few additional exposures before being fully acquired
o Repeated exposures to a single fact strengthen semantic memory for that fact
• Repeated exposure to very similar events may weaken episodic memory for any of those events
(parking lot confusion with where you parked days before
ASSESSING EPISODIC AND SEMANTIC MEMORIES IN ANIMALS
Semantic memory can be easily assessed in humans by asking them questions. This is not the case for
animals
Rat experiment: radial arm maze à task that is used to assess semantic memory in rats
• A maze with a central area from which several arms branch off like the spokes of a wheel. The top of
the maze is open so a rat placed in the maze can see out and use landmarks of the room (ex.
Placement of posters)
• ‘goal arm’ and ‘start arm’, rat learns where the food is located after practice and when it is placed
in the start arm it will run straight to the goal arm
• Rat ‘knows’ where the food is when trained and can still find food from a new start arm (using a new
route)
Episodic memories in animals are harder to assess and there is controversy about whether animals can form
episodic memories at all
• Some researchers think that animals cannot form episodic memories because an episodic memory
requires re-experiencing the event in memory, which requires a conscious sense of self, which has
not been (according to them) demonstrated in nonhumans
• Endel Tulving argued that episodic memory requires ‘mental time travel’ (reexperiencing of the
event in memory) which requires a conscious sense of self, as well as subjective sense of time
passing, so nonhumans did not demonstrate
• BUT other researchers argue there IS evidence that animals can form episodic like memories
• Study: a gorilla named King was taught how to refer to various fruits and humans by using cards with
drawings that represented the fruits and humans
