Memory
The Case of H.M.
Figure 14.19 MRI scans of the normal and damaged hippocampus
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers
Changes since lobectomy
•
•
•
•
Only one or two minor seizures per day
Reduced medication
IQ was slightly above average
Normal perceptual and motor abilities
• Serious problems with memory
• http://www.nytimes.com/2008/12/05/us/05hm.ht
ml?_r=1&pagewanted=1&em
Memory Tests
Memory tests he could not do as
well as a normal person
• Digit Span + 1 Test
• Block-Tapping + 1 Test
This is why…
• Short-term memory was fine
– STM stores a limited amount of information
for a limited amount of time (about 15
seconds)
• Long-term memory was compromised
– LTM stores an unlimited amount of
information for an unlimited amount of time
Other Memory Tests
Mirror-Drawing Test
Figure 14.17 The mirror tracing task
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers
Rotary-Pursuit Task
Declarative vs. Procedural memory
Declarative memory
• Digit span
• Block tapping
Procedural memory
• Mirror drawing
• Rotary pursuit
Explicit vs. Implicit memory
H. M.’s Memory Problems
• Mild retrograde amnesia
– Events that happened before surgery; e.g.
where he went to elementary school
• Severe anterograde amnesia
– Events that happened after surgery
Other Distinctions
Semantic memory
• General facts
• Information
• E.g.
Episodic memory
• Particular events or
experiences in one’s
life
• E.g.
Figure 14.4 Types of long-term memory
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers
The Atkinson-Shiffrin Model
• Memory storage has three stages
• Sensory register
– 0.5 to 1 second
• Short-term store
– Duration depends on
• Rehearsal
• Amount of information – distraction
• Long-term store
– Permanent
The Atkinson-Shiffrin Model
• Interference
– Retroactive interference
– Proactive interference
Posttraumatic Amnesia
Normal
functioning
Retrograde
amnesia
Blow to
the head
Anterograde
amnesia
Normal
functioning
Consolidation
Converting short-term memory to
long-term memory
Consolidation
• Hebb’s theory
• An experience triggers activity in a circuit of
neurons in the central nervous system
– Reverberation
• The circuit of neurons is called a “cell assembly”
• Eventually, the neurons in the cell assembly
change (e.g., shape of terminal button, number
of receptors)
• This causes memories to be now be stored in
the long term
Consolidation
• If process is disrupted, then unable to
permanently store new memory
– ECT
• Problem with this theory: the period of
retrograde amnesia can be for years
Role of the Hippocampus in
Memory
Figure 2.23 The limbic system
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers
Role of the Hippocampus in
Memory
• Hippocampus is part
of the limbic system,
in the forebrain
• The hippocampus is
involved in storing
new memories
Frontal and temporal lobes
• Frontal and temporal lobes are active
during retrieval of memories
Other Parts of the Brain
Associated with Memory
Amygdala
• Memories for
frightening events
Figure 2.23 The limbic system
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers
Prefrontal cortex
• Long-term working
memory
• Cooking Thanksgiving
dinner
Figure 2.25 The cerebral cortex, dorsal and lateral views
Klein/Thorne: Biological Psychology
© 2007 by Worth Publishers
Cerebellum
• Learned movements
Why you should not cram when
studying for exams
• protein phosphatase 1
Why you should not cram when
studying for exams
• Notes
Dr. Elizabeth Loftus
Loftus (2003)
Discussion
Your memories of your past have a great
influence on your sense of who you are as
a unique person. Yet, as Elizabeth Loftus
demonstrated, memories are easily altered
or distorted. What implications does this
have with regard to a person’s sense of
self?
• What are the broader implications of
Loftus’ findings?
• What are the limitations of Loftus’
findings?