Transcript Introduction to Cognitive Psychology

Reliability: Capable of being relied on;
dependable.
The two perspectives: Is memory as a cognitive
process reliable?
 Perspective 1: Memory is reliable (our brain
recalls the details of our experiences that are
deemed “important”)
 Perspective 2: Memory is not reliable (through
false memories, cultural schemas, encoding
failure, etc.)
Although many researchers argue that memory is
reliable from the “personal” significance
standpoint.
I will present a case of the unreliability of memory
from multiple perspectives.
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The brain's main depressant neurotransmitter
GABA regulates how easily we form new neural
connections when presented with new sensory
information.
It has been known for some time that the
connections between neurons in the
hippocampus, the brain's main memory center,
vary significantly in strength.
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The variation in strength, however, turns out to
correlate with the ability to form new memories,
reports a Tel Aviv research team in the August 2010
issue of "Neuron."
The researchers found that GABA weakens
synaptic connections between neurons in the
hippocampus, allowing for new memories to form.
Impairments to the GABA pathway or an increase
in chemicals that strengthen synaptic connections
are thus significant predictors of encoding failure or
memory loss.
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Memory is often unreliable because we fail to
encode the information. So the information never
entered the long-term memory.
Encoding efficiency is affected by age, which
explains age-related memory decline.
The brain areas that are active when encoding
new information are more responsive in young
adults than in old adults.
This would suggest that memory unreliability can
be due to biological factors beyond our control
(such as neurotransmission that may cause
attention deficit, lesions in the hippocampus,
etc.)
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Nevertheless, young or old, we are selectively
attentive. We encode some information
automatically, but other types of information
require effortful processing.
So without effort, many memories never form. For
example, we have a hard time remembering
how a real penny looks like because its details
are not that critical or meaningful.
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We cannot remember what we do not
encode.
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The idea that we do not remember things as they
actually happened is usually attributed to Sir
Frederick Bartlett (1886-1969)
He describes the process of memory in his classic
1932 book, Remembering: A Study in
Experimental and Social Psychology:
Bartlett stated:
 Remembering is not a completely independent
function, entirely distinct from perceiving,
imaging, or even from constructive thinking, but it
has intimate relations with them all…
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One’s memory of an event reflects a blend of
information contained in specific traces
encoded at the time it occurred, plus inferences
based on knowledge, expectations, beliefs, and
attitudes derived from other sources.
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According to Bartlett, memories are organized
within the historical and cultural frameworks
(which Bartlett called ‘schemata’) of the
individual, and the process of remembering
involves the retrieval of information which has
been unknowingly altered in order that it is
compatible with pre-existing knowledge.
Thus, even the way we encode our experiences is
subjective to the cultural and social context of
the experience.
Bartlett’s research on reconstructive memories
inspired many psychologist including Elizabeth
Loftus.
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Elizabeth Loftus, a professor
of psychology and law at the
University of California, Irvine,
has devoted her career to
studying the reconstructive
nature of memory in relation
to eyewitness testimony.
Her research strongly supports
that idea that memories can
be reconstructed and
unreliable.
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Loftus’ research has applied
the idea of unreliability to
memories to real world
situations such as eye witness
testimonies and false
memories.
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Loftus’ research has applied the idea of
unreliability to memories to real world
situations such as eye witness testimonies and
false memories.
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Loftus is concerned mainly with how the
recollections of eyewitnesses can be
deliberately manipulated by misinformation.
In extreme cases, this can lead to completely
false memories of events that did not take
place.
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One of Loftus’s more famous studies addresses
the use of ‘leading’ questions in the courtroom.
In the study, students were shown film clips of a
car accident, and then asked a question
about the accident.
Those asked “About how fast were the cars
going when they smashed into each other?”
gave answers which averaged about 39 mph,
whereas those asked “About how fast were
the cars going when they contacted each
other?” gave answers with an average speed
of 32 mph
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Loftus’s research, like that of Bartlett’s, shows
that our memories are quite often not as
accurate as we would like to think they are.
The knowledge that memory is to some extent
confabulation has very serious implications for
the use in the courtroom of eyewitness
testimonies, because if eyewitness testimonies
can be unreliable, then the validity of criminal
convictions based upon them is open to
question.
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Some people would have us think that the
memory is like a tape recorder that records
every event accurately and keeps it intact.
But, research on memory has debunked that
myth and raised many questions about
common misconceptions about remembering
and even our creation of false memories.
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For instance, how accurate are childhood memories?
Does the vividness of the recall increase the validity of
a memory?
The Swiss psychologist Jean Piaget describes a clear
memory from his own early childhood:
“I can still see, most clearly, the following scene, in
which I believed until I was about fifteen. I was sitting in my
pram, which my nurse was pushing in the Champs Elysées,
when a man tried to kidnap me. I was held in by the strap
fastened round me while my nurse bravely tried to stand
between me and the thief. She received various
scratches, and I can still see vaguely those on her face.
Then a crowd gathered, a policeman with a short cloak
and a white baton came up, and the man took to his
heels. I can still see the whole scene, and can even place
it near the tube station.”
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Notice the details of this memory. Nevertheless,
Piaget then says his clear memory is of an
event that never happened. His nurse had
confessed when he was about fifteen years
old. Piaget says:
She had made up the whole story, faking the
scratches. I, therefore, must have heard, as a
child, the account of this story, which my
parents believed, and projected into the past
in the form of a visual memory.
Thus, our brains can encode memories,
erroneously, from other things that we
experience.
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Loftus begins her book Memory: Surprising New
Insights into How We Remember and Why We
Forget by describing her own memory of her father
after he died. At first, her thoughts of him were
filled with recent images of him suffering the final
stages of cancer. She says:
Then, gradually, my thoughts of him began to
include some happier images. I saw him standing
in the yard, holding a scrawny cat. I saw him in the
living room surrounded by smiling family. I even
thought about him holding me on his lap when I
was no older than four.
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Then she realized the source of those
memories. She had photographs of each
event. She was remembering the pictures.
Thus, her memory was enhanced by additional
visual information.
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Remembering is not running an invisible tape
recorder back to an event.
It is pulling together bits and pieces of
information that logically fit together.
Even immediate recall may be inaccurate
simply because of an initial failure to perceive
accurately.
That is why two people who recall a particular
event may have two completely different
stories. Can our memories of the past change
with clarity or suggestion from others?
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Memories are also very malleable. They
change even as we recall past events.
Loftus says:
With the passage of time, with proper
motivation, with the introduction of special
kinds of interfering facts, the memory traces
seem sometimes to change or become
transformed.
These distortions can be quite frightening, for
they can cause us to have memories of things
that never happened.
Further research:
Loftus Study on Reconstructive memories
https://webfiles.uci.edu/eloftus/LoftusPalmer74.pd
f
 False memories
http://www.ishk.net/myth_of_repressed_memory.
pdf
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Attentional Bias – implicit cognitive bias
defined as the tendency of emotionally
dominant stimuli in one's environment to
preferentially draw and hold attention.
Confirmation bias – the tendency to search for
or interpret information in a way that confirms
one's preconceptions
Hindsight bias – sometimes called the "I-knewit-all-along" effect, the tendency to see past
events as being predictable[31] at the time
those events happened.(sometimes phrased
as "Hindsight is 20/20")
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Researchers employ a variety of techniques to
investigate brain activity, though in the everchanging landscape of technology, these
methods continue to evolve.
Under the assumption that states “cognitive
processes have a biological origin, we can
investigate cognitive process through
physiological processes.
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Two of the more traditional methods used to
study the brain include position emission
tomography (PET) and functional MRI (fMRI)
scans.
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During a PET scan, a patient is injected with a
dose of radioactive compound, typically
flourodeoxyglucose (FDG), a type of glucose
molecule.
Once the FDG is in a person's blood, it is
carried to the brain, where it is absorbed.
Glucose (a type of sugar) is the brain's primary
energy source so the active regions soak it up - the more active the area of the brain, the
more glucose that is absorbed.
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The FDG is radioactive, meaning radioactive
elements are also absorbed by the brain.
The PET scan machine then detects the
radioactive energy given off by this
compound, and uses a computer to convert
the data into 3-D images, with different colors
highlighting which areas of a brain are most
active.
PET scans on the brain are typically used to
detect changes in the brain that may cause
cognitive disorders such as Alzheimer's and
Schizophrenia, and find cancerous tumors.
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Alzheimer's disease is a progressive and
irreversible neurological disorder which attacks
brain cells and causes memory loss, confusion,
language problems, and sometimes an
incapacity to form new memories.
In Alzheimer's disease and other forms of
dementia, the brain produces a metabolic
pattern that is significantly different from the
metabolic pattern of healthy brain cells.
PET scans taken in 2000 show the metabolic degeneration of
the brain of a patient with Alzheimer's as it progressively reduces brain function.
(UCLA Center on Aging)
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As PET imaging examines the metabolic
activity of brain cells by tracing how FDG is
absorbed, it is able to detect Alzheimer's
disease and other forms of dementia.
PET scans have become a way in which
doctors are able to confirm the presence of
the disease in a noninvasive and painless way.
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There is no cure for Alzheimer's however there
are now new drug therapies which can delay
the progression of the disease, but to perform
this early detection is needed.
A PET scan enables us to see the biological
changes in the brain caused by the disease.
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Recent medical studies have suggested using
PET scanning of the hippocampus as a way to
detect Alzheimer's disease while in its early
stages.
Hippocampal glucose metabolism reductions
are found in both mild cognitive impairment
and Alzheimer disease and contribute to their
diagnostic classification.
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A PET scan differs from other types of imaging
technology (MRI, CT scan, and x-ray) in that it
displays the chemical function of a particular
organ or section of tissue.
PET scans are able to detect biochemical and
metabolic changes suggesting disease before
they are detected by standard imaging
devices.
Another benefit associated with PET scanning is
that the radiation dosage is relatively low,
equivalent to about half that of a CT scan.
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Functional magnetic resonance imaging, or
fMRI, is a technique for measuring brain
activity.
It works by detecting the changes in blood
oxygenation and flow that occur in response
to neural activity – when a brain area is more
active it consumes more oxygen and to meet
this increased demand blood flow increases
to the active area.
fMRI can be used to produce activation maps
showing which parts of the brain are involved
in a particular mental process.
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The development of FMRI in the 1990s, generally
credited to Seiji Ogawa and Ken Kwong, is the
latest in long line of innovations, including positron
emission tomography (PET) and near infrared
spectroscopy (NIRS), which use blood flow and
oxygen metabolism to infer brain activity. As a
brain imaging technique FMRI has several
significant advantages:
1. It is non-invasive and doesn’t involve radiation,
making it safe for the subject.
2. It has excellent spatial and good temporal
resolution.
3. It is easy for the experimenter to use.
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The development of FMRI in the 1990s, generally
credited to Seiji Ogawa and Ken Kwong, is the
latest in long line of innovations, including positron
emission tomography (PET) and near infrared
spectroscopy (NIRS), which use blood flow and
oxygen metabolism to infer brain activity. As a
brain imaging technique FMRI has several
significant advantages:
1. It is non-invasive and doesn’t involve radiation,
making it safe for the subject.
2. It has excellent spatial and good temporal
resolution.
3. It is easy for the experimenter to use.
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The attractions of FMRI have made it a
popular tool for imaging normal brain function
– especially for psychologists.
Over the last decade it has provided new
insight to the investigation of cognitive
processes such as how memories are formed,
language, pain, learning and emotion.
settings.
fMRIs have even been used to investigate
cognitive functioning in criminals.