Download Human Memory

Human Memory
It is good to have an end to
journey towards; but it is the
journey that matters, in the end.
Ursula K. Le Gui
The Memory Process
Three step process….
1. Encoding: The processing
of information into the
memory system.
2. Storage: The retention of
encoded material over
time.
3. Retrieval: The process of
getting the information
out of memory storage.
Information Processing
Model of Memory
Sensory Memory
• Stores all the stimuli that
register on the senses
• Lasts up to three seconds
• Two types
Sensory
Input
Sensory
Memory
– Iconic memory
• Visual
• Usually lasts about 0.3
seconds
• Sperling’s tests (1960s)
– Echoic memory (we’ll
come back to this)
Sperling’s Experiment
• Presented matrix of letters
for 1/20 seconds
– Report as many letters as
possible
• Subjects recalled only half of
the letters
• Was this because subjects
didn’t have enough time to
view entire matrix?
– No
• How did Sperling know this?
Sperling’s Iconic Memory Experiment
Sperling’s Iconic Memory Experiment
Sperling’s Iconic Memory Experiment
Sperling’s Iconic Memory Experiment
Sperling’s Experiment
• Sounded low, medium or
high tone immediately
after matrix disappeared
– Tone signaled 1 row to
report
– Recall was almost perfect
• Memory for images fades
after 1/3 seconds or so,
making report of entire
display hard to do
High
Medium
Low
Sensory Memory
• Echoic memory
– Sensory memory for auditory input that
lasts only 2 to 3 seconds
• Why do we need sensory memory?
Short-term Memory
• Function
– Conscious processing of information
– Attention is the key
• Limits what info comes under the spotlight of
short-term memory at any given time
• AKA working memory
Sensory
Input
Attention
Sensory
Memory
Working or
Short-term
Memory
Short-term Memory
• Limited capacity
– Can hold 7 ± 2 items for about 20 seconds
– Maintenance rehearsal
• The use of repetition to keep info in short-term memory
• CHUNK
– Meaningful unit of information
– Without rehearsal, we remember 4 ± 2 chunks
– With rehearsal, we remember 7 ± 2 chunks
– Ericsson & Chase (1982)
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Long-term Memory
• Once information passes from
sensory to short-term memory, it can
be encoded into long-term memory
Retrieval
Sensory
Input
Encoding
Attention
Sensory
Memory
Working or
Short-term
Memory
Long-term
memory
Explicit Memories
• Episodic Memories
• Semantic Memories
Implicit Memories
• Procedural Memories
• Conditioned Memories
Take out a piece of paper and name
all the Presidents…
Encoding Information
• Primacy Effect
• Recency Effect
• Serial Positioning
Effect
Spacing Effect
• DO NOT CRAM!!!!!!!!!!!!
• Ebbinghaus’s Forgetting Curve
The Ways we can encode…
• Visual Encoding: the
encoding of picture
images.
• Acoustic Encoding:
the encoding of
sound, especially the
sounds of words.
• Semantic Encoding:
the encoding of
meaning.
Long-term memory - Encoding
• Elaborative rehearsal
– A technique for transferring information into longterm memory by thinking about it in a deeper way
• Levels of processing
– Semantic is more effective than visual or acoustic
processing
– Craik & Tulving (1975)
• Self-referent effect
– By viewing new info as relevant to the self, we
consider that info more fully and are better able to
recall it
Semantic Networks
Bus
Truck
Ambulance
Orange
House
Fire Engine
Fire
Yellow
Green
Red
Apples
Cherry
Roses
Sunrise
Daisies
Flowers
Sunsets
Clouds
Take out a piece of paper…..
• Name the seven
dwarves…..
Now name them…..
Was it easy or hard?
• It depends on
several things….
• If you like Disney
movies?
• When was the last
time you have seen
the movie?
• Are people around
you being loud pain in
the butts so you
cannot concentrate?
Recall Versus Recognition
Recall
• you must retrieve the
information from your
memory
• fill-in-the blank or essay
tests
Recognition
• you must identify the
target from possible
targets
• multiple-choice tests
Retrieval – Explicit Memory
• Context-Dependent Memory
– We are more successful at retrieving
memories if we are in the same
environment in which we stored them
• State-Dependent Memory
– We are more successful at retrieving
memories if we are in the same mood as
when we stored them
Retrieval – Implicit Memory
• Showing knowledge of something without
recognizing that we know it
• Research with amnesics
• Déjà vu
– The illusion that a new situation is familiar
• Eyewitness testimony
– Eyewitness transference
• Unintentional plagiarism
Forgetting
If we remembered everything, we should on
most occasions be as ill off as if we
remembered nothing.
William James
• Lack of encoding
– Often, we don’t even encode the features
necessary to ‘remember’ an object/event
• Decay
– Memory traces erode with the passage of time
– No longer a valid theory of forgetting
– Jenkins & Dallenbach (1924)
Forgetting
Forgetting
• Retroactive
Interference: new
information blocks
out old information.
Getting a new bus
number and
forgetting old bus
number.
• Proactive
Interference: old
information blocks
out new information.
Calling your new girlfriend by old
girlfriends name.
Storing Memories
Long Term-Potentiation
• long-lasting
enhancement in signal
transmission between
two neurons that
results from stimulating
them synchronously.
• In other words…they
learn to fire together
and get better at
it…creating a memory.
Forgetting
• Repression
– There are times when we are unable
to remember painful past events
– While there is no laboratory
evidence for this, case studies
suggest that memories
can be repressed for a
number of years and
recovered in therapy
Improving Memory
• Practice time
– Distribute your studying over time
• Depth of processing
– Spend ‘quality’ time studying
• Verbal mnemonics
– Use rhyming or acronyms to reduce the
amount of info to be stored
Improving Memory
• Method of loci
– Items to be recalled are mentally placed in
familiar locations
• Interference
– Study right before sleeping & review all the
material right before the exam
– Allocate an uninterrupted chunk of time to
one course
Eyewitness Testimony
• Estimates of 2,000-10,000 wrongly
convicted in U.S. based on eyewitness
testimony
• Distortion
• Bias
• Inaccuracy