Chapter6.ppt

Chapter 6

Long-Term Memory: Structure

Some Questions to Consider

How does damage to the brain affect the ability to remember what has happened in the past and the ability to form new memories of ongoing experiences?
How are memories for personal experiences, like what you did last summer, different from memories for facts, like the capital of your state?
How do the different types of memory interact in our everyday experience?
How has memory loss been depicted in popular films?

Long-Term Memory

“Archive” of information about past events and knowledge learned
Works closely with working memory
Storage stretches from a few moments ago to as far back as one can remember
More recent memories are more detailed

Long-Term Memory

Serial Position Effect

Murdoch (1962) studied the distinction between short-term and long-term memories using the serial position curve
He asked participants to read a stimulus list (usually a list of words), and write down all the words they could remember.

Serial Position Curve

He found that memory is better for the stimuli presented at beginning which he called the primacy effect
Believed this was because you have more time to rehearse info presented at the beginning, and it is more likely to enter LTM

Serial Position Curve

Memory is also better for stimuli presented at end of list which he called the recency effect
He hypothesized that this was because the Stimuli at the end of the list are still in STM
Try it out:

Coding in Long-Term Memory

Visual and auditory encoding in short- and long-term memory
Some things are stored as visual memories and some as auditory.
It’s easier to remember words of things you can visualize like “cat” as opposed to “hope”.
It’s easier to remember words when they don’t sound similar to each other.
Semantic encoding in short- and long-term memory (Wickens et al., 1976)
If you look at group B to the right, interference is caused when fruits are surprisingly presented after a series of professions.
The meaning and relatedness of words affects or short and long-term memories.

Coding in Long-Term Memory

Semantic encoding (memory for words) in long-term memory
One way to test semantic coding is to look at recognition memory: how well can you identify a previously encountered stimulus
Sachs (1967)
Asked participants to read paragraphs. After a delay asked them to choose which sentence was written directly as an original sentence in the paragraph.
The results showed that specific wording is forgotten but the general meaning of the sentence can be remembered.
I always tell students that to avoid plagiarism, they need to read their source and then put it away and not look at it again while summarizing a paper or article.
It is almost impossible to remember and rewrite exact sentences from the paper.

Locating Memory in the Brain

Neuropsychology
The hippocampus is responsible for one’s ability to encode new long-term memories
We know this from several amazing case studies. Watch the videos for more information.
Henry Molaison (H.M.) – hippocampus removed to treat his severe epilepsy
Clive Wearing- lost his memory from encephalitis

Types of Long-Term Memory

Episodic: memory for personal events
First day of kindergarten
Wedding day
Graduation
We generally have no episodic memories of things that happened before age 2
Semantic: facts and knowledge not drawn from personal experience.
Christopher Columbus discovered America
George Washington was the first president.

Types of Long-Term Memory

Episodic involves mental time travel
No guarantee of accuracy
Semantic does not involve mental time travel
General knowledge
Episodic and semantic show a double dissociation

Separation of Episodic and Semantic Memories

K.C. damaged hippocampus in a motorcycle accident
No episodic memory
He cannot relive any events of his past
Semantic memory remained intact
He can remember general information about the past;
This indicates that episodic and semantic memory are two different processes that have different origins in the brain.

Separation of Episodic and
Semantic Memories

The opposite can also happen in which semantic memory is impaired but episodic memory is preserved
Italian woman
Had encephalitis
Impaired semantic memory
Couldn’t remember the meanings of words
Couldn’t recognize people
Episodic memory for past events was preserved
Could remember things she had done herself

Separation of Episodic and Semantic Memories

Evidence from brain-imaging experiments indicates that retrieving episodic and semantic memories activate different areas of the brain.
Alzheimer’s disease greatly affects episodic memory
Semantic dementia tends to affect semantic memory
People still remember their own past but forget facts

Interactions Between Episodic and Semantic Memories

Episodic can be lost, leaving only semantic
Acquiring knowledge may start as episodic but then “fade” to semantic
Semantic can be enhanced if associated with episodic
Autobiographical memory: memory of specific experiences, includes semantic and episodic
Personal semantic memory: semantic memories that have personal significance
Can influence what we experience (episodic) by determining what we attend to

The Effect of Time

Typical research findings are that forgetting increases with longer intervals from the original encoding
Remember/Know procedure
Remember if a stimulus is familiar and the circumstance under which it was encountered?
Know if the stimulus is familiar but don’t remember experiencing it earlier?
Don’t remember the stimulus at all
Semanticization of remote memories
Loss of episodic details for memories of long-ago events

Types of Long-Term Memory

Explicit memory (episodic and semantic) are conscious, in that we are aware that learning is taking place.
Implicit memory is not conscious.
memory that unconsciously influences behavior
Repetition priming
Procedural memory (often called “muscle memory”)
Memory for processes like riding a bicycle, playing the piano, driving a car, tying your shoes
Classical conditioning

Types of Long-Term Memory

Implicit/non-declarative: unconscious memory
Procedural (skill) memory
Priming: previous experience changes response without conscious awareness
Explicit/declarative: unconscious memory
Episodic: personal events/episodes
Semantic: facts, knowledge

Implicit Memory: Procedural Memory

Skill memory: memory for actions
No memory of where or when learned
Perform procedures without being consciously aware of how to do them
People who cannot form new long-term memories can still learn new skills (e.g., H.M.)
Clive Wearing, a famous musician and conductor, lost hislong-term memory but could still play the piano as well as ever.

Repetition Priming

Presentation of one stimulus affects performance on that stimulus when it is presented again
Graf and coworkers (1985)
Texted explicit memory and implicit memory
Tested three groups

Amnesia patients with Korsakoff’s syndrome

Korsakoff’s syndrome is long-term memory loss due to alcoholism.

Patients without amnesia being treated for alcoholism

Patients with amnesia who had no history of alcoholism

Repetition Priming

Implicit Memory in Everyday Experience

Perfect and Askew (1994)
Propaganda effect
We are more likely to rate statements read or heard before as being true even if they are not true.
Implications for advertisements

Implicit Memory: Classical Conditioning

Pairing a neutral stimulus with a reflexive response
We and other animals are not intentionally learning. It is a subconscious, reflexive response.
It is also used in advertising, to influence our feelings about products.

Chapter6.ppt

Chapter6.ppt

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