lecture 21 from a college level introduction to psychology course taught Fall 2011 by Brian J. Piper, Ph.D. (psy391@gmail.com) at Willamette University, includes hippocampus, cerebellum, H.M., explicit & implicit memory, priming, context effect, misinformation, Loftus, constructed memories

1. Memory II: Retrieval & Forgetting
Brian J. Piper, Ph.D.

2. Objectives
• Neurobiology of Memory
• Retrieval
• (Mis)remembering

3. Storing Memories in the Brain I
1. Karl Lashley (1950) suggested that even
after removing parts of the rat brain, the
animals retain memory of the maze.
1890-1958

4. Storing Memories in the Brain II
2. Loftus and Loftus (1980) reviewed previous
research data showing, through brain
stimulation, that experiences were etched into
the brain and found that only a minority (3%) of
brain stimulated patients reported events.
Wilder Penfield
1891-1976
Loftus & Loftus, 1980, American Psychologist, 35, 309-420.

5. Memory or Dream?
Secondary Source (Blakemore, 1977, New York Times, p. 88):
One -of Penfield's patients was a young woman. As the stimulating electrode touched a spot
on her temporal lobe, she cried out: "I think I heard a mother calling her little boy
somewhere. It seemed to be something that happened years ago . . . in the neighborhood
where I live." Then the electrode was moved a little and she said, "I hear voices. It is late at
night, around the carnival somewhere—some sort of traveling circus. I just saw lots of big
wagons that they use to haul animals in.“ There can be little doubt that Wilder Penfield's
electrodes were arousing activity in the hippocampus, within the temporal lobe, jerking out
distant and intimate memories from the patient's stream of consciousness.
Primary Source
The flashback responses to electrical stimulation . . .bear no relation to present experience
in the operating room. Consciousness for the moment is doubled, and the patient can
discuss the phenomenon. If he is hearing music, he can hum in time to it. The astonishing
aspect of the phenomenon is that suddenly he is aware of all that was in his mind during an
earlier strip of time. It is the stream of a former consciousness flowing again, if music is
heard, it may be orchestra or voice or piano. Sometimes he is aware of all he was seeing at
the moment; sometimes he is aware only of the music. It stops when the electrode is lifted.
It may be repeated (even many times) if the electrode is replaced without too long a
delay. This electrical recall is completely at random. Most often, the event was neither
significant nor important. (Penfield, 1969, p. 152)

6. Synaptic Changes
In Aplysia, Kandel and Schwartz (1982) showed
that serotonin release from neurons increased
after conditioning.

7. Synaptic Changes
Long-Term Potentiation
Both Photos: From N. Toni et al., Nature, 402, Nov. 25 1999. Courtesy of Dominique Muller
(LTP) refers to synaptic
enhancement after
learning (Lynch, 2002).
An increase in
neurotransmitter release
or receptors on the
receiving neuron
indicates strengthening
of synapses.

8. Stress Hormones & Memory
Heightened emotions (stress-related or
otherwise) make for stronger memories.
Flashbulb memories are clear memories of
emotionally significant moments or events
Scott Barbour/ Getty Images

9. Storing Implicit & Explicit Memories
Explicit Memory refers to facts and experiences that one
can consciously know and declare. Implicit memory
involves learning an action while the individual does not
know or declare what she knows.

10. Hippocampus
Hippocampus – a neural center in the limbic
system that processes explicit memories.
Weidenfield & Nicolson archives

11. Anterograde Amnesia
After losing his hippocampus in surgery, patient
Henry Molaison (HM) remembered everything
before the operation but cannot make new
memories. We call this anterograde amnesia.
Anterograde
Amnesia
Memory Intact No New Memories
(HM)
Surgery

12. Implicit Memory
HM is unable to make new memories that are
declarative (explicit), but he can form new
memories that are procedural (implicit).
A B C
HM learned the Tower of Hanoi (game) after his surgery. Each time
he plays it, he is unable to remember the fact that he has already
played the game.

13. Cerebellum
Cerebellum – a neural center in the hindbrain
that processes implicit memories.

14. Retrieval: Getting
Information Out
 Retrieval Cues

15. Retrieval: Getting Information Out
Retrieval refers to getting information out of
the memory store.

16. Measures of Memory
In recognition, the person must identify an item
amongst other choices. (A multiple-choice test
requires recognition.)
1. Name the capital of France.
a. Brussels
b. Rome
c. London
d. Paris

17. Measures of Memory
In recall, the person must retrieve information
using effort. (A fill-in-the blank test requires
recall.)
1. The capital of France is ______.

18. Measures of Memory
In relearning, the individual shows how much
time (or effort) is saved when learning material
for the second time.
List List
Jet Jet
Original Relearning
Dagger Dagger Trials Trials
Tree Tree Saving X 100
1 day later Relearning
Kite Kite
… … Trials
Silk Silk 10 5
X 100
Frog Frog 10
Ring Ring
It took 10 trials It took 5 trials 50%
to learn this list to learn the list

19. Retrieval Cues
Memories are held in storage by a web of
associations. These associations are like anchors
that help retrieve memory.
water
smell
hose
Fire Truck
fire
smoke truck
heat
red

20. Priming
To retrieve a specific memory from the web of
associations, you must first activate one of the
strands that leads to it. This process is called
priming.

21. Context Effects
Scuba divers recall more words underwater if they
learned the list underwater, while they recall more
words on land if they learned that list on land.
rs
Godden & Baddley (1975). British J of Psychology, 66, 325-331.

22. Déjà Vu
Déjà Vu means “I've experienced this before.”
Cues from the current situation may trigger
retrieval of an earlier similar experience.
cartoonbank.com. All Rights Reserved
© The New Yorker Collection, 1990. Leo Cullum from

23. Context Effects
After learning to move a mobile by
kicking, infants most strongly respond when
retested in the same context rather than in a
different context.
http://www.youtube.com/watch?v=lPJiB-oGMN0
Rovee-Collier, C. (1993). Current Directions in Psychological Science, 2, 130-135.

24. Context Effects
------------------------------------------------------
Retention Ratio = kicking during long-term memory test / immediate post-learning kicking
Rovee-Collier, C. (1993). Current Directions in Psychological Science, 2, 130-135.

25. Moods and Memories
We usually recall experiences that are consistent
with our current mood (state-dependent
memory). Emotions, or moods, serve as retrieval
cues. Our memories are mood-congruent.
Jorgen Schytte/ Still Pictures

26. Forgetting
 Encoding Failure
 Storage Decay
 Retrieval Failure

27. Forgetting
An inability to retrieve information due to
poor encoding, storage, or retrieval.

28. Encoding Failure
We cannot remember what we do not
encode.

29. Storage Decay
Poor durability of stored memories leads to
their decay. Ebbinghaus showed this with
his forgetting curve.

30. Retaining Spanish
Bahrick (1984) showed a similar pattern of
forgetting and retaining over 50 years.
Andrew Holbrooke/ Corbis
Bahrick (1984). Journal of Experimental Psychology, 113, 1-29.

31. Retrieval Failure
Although the information is retained in the
memory store, it cannot be accessed.
Tip-of-the-tongue (TOT) is a retrieval failure
phenomenon. Given a cue (What makes blood cells
red?) the subject says the word begins with an H
(hemoglobin).

32. Memory Construction
 Misinformation and Imagination
Effects
 Source Amnesia
 Discerning True and False Memories
 Children’s Eyewitness Recall
 Repressed or Constructed Memories of
Abuse?
Improving Memory

33. Interference
Learning some new information may disrupt
retrieval of other information.
French learned beforehand, interferes proactively with a Spanish exam.

34. Interference
Learning some new information may disrupt
retrieval of other information.

35. Retroactive Interference
Sleep prevents retroactive interference. Therefore, it
leads to better recall.

36. Why do we forget?
Forgetting can occur at
any memory stage. We
filter, alter, or lose
much information
during these stages.

37. Forgetting Example
2008 Memory of Bosnia Trip
I remember landing under sniper fire. There
was supposed to be some kind of a greeting
ceremony at the airport, but instead we just
ran with our heads down to get into the
vehicles to get to our base.

38. Actual 1996 Bosnia Trip
• Quiet & Uneventful
• H.C. “I made a mistake. I had a different memory.
I made a mistake-that happens-that proves I’m
human which for some people is a revelation.”
• Four Pinnocchios
– No corkscrew landing
– No sniper fire
– No cancelled airport reception
– Not 1st first lady to go into war zone.

39. Memory Construction
While tapping our memories, we filter or fill in
missing pieces of information to make our
recall more coherent.
Misinformation Effect: Incorporating
misleading information into one's memory of
an event.
1944-

40. Misinformation and Imagination Effects
Eyewitnesses reconstruct their memories when
questioned about the event.
Depiction of the actual accident.

41. Misinformation
Group A: How fast were the cars going
when they hit each other?
Group B: How fast were the cars going
when they smashed into each
other?

42. Memory Construction
A week later they were asked: Was there any
broken glass? Group B (smashed into) reported
more broken glass than Group A (hit).
50
Broken Glass? (%)
40
32
30
20 14
10
0
Group A (hit) Group B (Smashed into)
Verb

43. Source Amnesia
Source Amnesia: Attributing an event to the
wrong source that we
experienced, heard, read, or imagined
(misattribution).
Demonstration of Recognition Memory (14:00 – 18:30)
http://fora.tv/2009/07/14/Elizabeth_Loftus_Whats_the_Matter_with_Memory

44. Children’s Eyewitness Recall
Children’s eyewitness recall can be unreliable if
leading questions are posed. However, if
cognitive interviews are neutrally worded, the
accuracy of their recall increases. In cases of
sexual abuse, this usually suggests a lower
percentage of abuse.

45. Memories of Abuse
Are memories of abuse repressed or
constructed?
Many psychotherapists believe that early
childhood sexual abuse results in repressed
memories.
However, other psychologists question such
beliefs and think that such memories may be
constructed.

46. Constructed Memories
1944-
Loftus’ research shows that if false memories (lost at
the mall or drowned in a lake) are implanted in
individuals, they construct (fabricate) their
memories.
Examples: Push Polling: If you knew that Candidate Smith was being investigated for
corruption, would you be more likely to vote for him, or less likely?
“controversial theory of __________ “

47. Consensus on Childhood Abuse
Leading psychological associations of the world agree
on the following concerning childhood sexual abuse:
1. Injustice happens.
2. Incest and other sexual abuse happen.
3. People may forget.
4. Recovered memories are commonplace.
5. Recovered memories under hypnosis or drugs are
unreliable.
6. Memories of things happening before 3 years of age
are unreliable.
7. Memories, whether real or false, are emotionally
upsetting.

48. Summary: Improving Memory
1. Study repeatedly to boost long-term recall.
2. Spend more time rehearsing or actively
thinking about the material.
3. Make material personally meaningful.
4. Use mnemonic devices:
 associate with peg words — something already
stored
 make up a story
 chunk — acronyms

49. Improving Memory
5. Activate retrieval cues — mentally recreate
the situation and mood.
6. Recall events while they are fresh — before
you encounter misinformation.
7. Minimize interference:
1. Test your own knowledge.
2. Rehearse and then determine what you do not
yet know.