Essay/Term paper: Memory

Essay, term paper, research paper:  Biology

Memory


Memory is defined as the faculty by which sense impressions and
information are retained in the mind and subsequently recalled. A person"s
capacity to remember and the total store of mentally retained impressions and
knowledge also formulate memory. (Webster, 1992)
"We all possess inside our heads a system for declassifying, storing and
retrieving information that exceeds the best computer capacity, flexibility, and
speed. Yet the same system is so limited and unreliable that it cannot
consistently remember a nine-digit phone number long enough to dial it"
(Baddeley, 1993). The examination of human behavior reveals that current
activities are inescapably linked by memories. General "competent" (1993)
behavior requires that certain past events have effect on the influences in the
present. For example, touching a hot stove would cause a burn and therefore
memory would convey a message to not repeat again. All of this is effected by
the development of short-term memory (STM) and long-term memory (LTM).
Memories can be positive, like memories of girlfriends and special events,
or they can be negative, such as suppressed memories. Sexual abuse of children
and adolescents is known to cause severe psychological and emotional damage.
Adults who were sexually abused in childhood are at a higher risk for developing
a variety of psychiatric disorders, anxiety disorders, personality disorders,
and mood disorders. To understand the essential issues about traumatic memory,
the human mind"s response to a traumatic event must first be understood. The
memory is made up of many different sections with each having different
consequences on one another.
Can people remember what they were wearing three days ago? Most likely no,
because the memory only holds on to what is actively remembered. What a person
was wearing is not important so it is thrown out and forgotten. This type of
unimportant information passes through the short-term memory. "Short-term
memory is a system for storing information over brief intervals of time."
(Squire, 1987) It"s main characteristic is the holding and understanding of
limited amounts of information. The system can grasp brief ideas which would
otherwise slip into oblivion, hold them, relate them and understand them for its
own purpose. (1987) Another aspect of STM was introduced by William James in
1890, under the name "primary memory" (Baddeley, 1993). Primary memory refers
to the information that forms the focus of current attention and that occupies
the stream of thought. "This information does not need to be brought back to
mind in order to be used" (1993). Compared to short-term memory, primary
memoryplaces less emphasis on time and more emphasis on the parts of attention,
processing, and holding. No matter what it is called, this system is used when
someone hears a telephone number and remembers it long enough to write it down.
(Squire, 1987)
Luckily, a telephone number only consists of seven digits or else no one
would be able to remember them. Most people can remember six or seven digits
while others only four or five and some up to nine or ten. This is measured by
a technique called the digit span, developed by a London school teacher, J.
Jacobs, in 1887. Jacobs took subjects (people), presented them with a sequence
of digits and required them to repeat the numbers back in the same order. The
length of the sequence is steadily increased until a point is reached at which
the subject always fails. The part at which a person is right half the time is
defined as their digit span. A way to improve a digit span is through rhythm
which helps to reduce the tendency to recall the numbers in the wrong order.
Also, to make sure a telephone number is copied correctly, numbers can be
grouped in twos and threes instead of given all at once. (Baddeley, 1993)
Another part of short-term memory is called chunking, used for the
immediate recall of letters rather than numbers. When told to remember and
repeat the letters q s v l e r c i i u k, only a person with an excellent
immediate memory would be able to do so. But, if the same letters were given
this way, q u i c k s i l v e r, the results would be different. What is the
difference between the two sequences? The first were 11 unrelated letters, and
the second were chunked into two words which makes this task easier. (1993)
"Short-term memory recall is slightly better for random numbers than for
random letters, which sometimes have similar sounds. It is better for
information heard rather than seen. Still, the basic principals hold true: At
any given moment, we can process only a very limited amount of information."
(Myers, 1995)
The next part in the memory process involves the encoding and merging of
information from short-term into long-term memory. Long-term memory is
understood as having three separate stages: transfer, storage, and retrieval.
Once information has entered LTM, with a size that appears to be essentially
unlimited, it is maintained by repetition or organization.
A major part of the transfer process concerns how learned information is
coded into memory. Long-term and short-term memory are thought to have
different organizations. Where the STM is seen as being organized by time, LTM
is organized by meaning and association then put into categories. For example,
our memory takes in Coke and Pepsi as drinks then organizes and puts them in
categories such as soda. An important role in the transferring of information
into long-term memory is rehearsal. The critical aspect is the type of rehearsal
or processing that takes place during the input time. "Simple repetition, which
serves only to maintain the immediate availability of an item, does little if
anything to enhance subsequent recall. Active processes such as elaboration,
transformation, and recoding are activities that have been found to enhance
recall." (Asken, 1987)
Information that is stored in LTM is stored in the same form as it was
originally encoded. Major forms of storage are episodic memory and semantic
memory. Episodic memory involves remembering particular incidents, such as
visiting the doctor a week ago. Semantic memory concerns knowledge about the
world. It holds meanings of words or any general information learned.
Knowledge of the capitals of all the states would be stored in semantic memory.
A Canadian psychologist, Endel Tulving discovered that there was more activity
in the front of the brain when episodic memories were being retrieved, compared
to more activity towards the back of the brain with semantic memory.
Retrieval, the third process related to LTM, is the finding and
retrieving of information from long-term storage. The cues necessary to
retrieve information from memory are the same cues that were used to encode the
material.
For some, positive memories are recalled through music. Certain songs
remind people of special times spent with friends. Couples sometimes have songs
that remind them of their time spent together. Everyone has some way of
remembering good times from the past.
Along with positive memories come the negative ones, which are
suppressed deep in our minds. Another word for negative is traumatic, an
experience beyond "the range of usual human experience," (Sidran Foundation,
1994) and is brought about with intense fear, terror and helplessness. Examples
include a serious threat to one"s life (or that of one"s children, spouse, etc.),
rape, military combat, natural or accidental disasters, and torture.
So how does trauma affect memory? People use their natural ability to
avoid concern of a traumatic experience while the trauma is happening. This
causes the memories about the traumatic events to emerge later. People with
Post Traumatic Stress Disorder (PTSD) who have survived horrific events
experience extreme recall of the event. Some people say they are haunted by
memories of traumatic experiences that disrupt their daily lives. They cannot
get the pictures of the trauma out of their head. This brings recurring
nightmares, flashbacks, or even reliving the trauma as if it were happening now.
Vietnam veterans experience this symptom because of what they saw and lived
through. Some researchers have proven in the laboratory that ordinary or
slightly stressful memories are easily distorted. However, this laboratory
research on ordinary memory may be irrelevant in regard to memories of traumatic
experiences. Other scientists argue that traumatic memories are different from
ordinary memories in the way they are encoded in the brain. Evidence shows
trauma is stored in the part of the brain called the limbic system, which
processes feelings and sensory input, but not language or speech. (1994)
People who have been traumatized may live with memories of terror, though with
little or no real memories to explain the feelings. Sometimes a current event
may trigger long forgotten memories of earlier trauma. The triggers may be any
sound or smell like a particular cologne which was worn by an attacker.
Whether remembered or not, the memories are stored in the brain, and
today with hypnosis, recall can bring forth what has been deeply suppressed.
The question is, does one really want to know what is not remembered? Along
with memories that are recovered, comes the effects that follow.
Short-term memory holds every experience encountered, while long-term
memory retains only what's important. Memory is stored through episodic and
semantic memory. The retrieval of decoded information occurs the same way it
was encoded. Memory is affected through positive and negative emotions, some
remembered others suppressed. Not only is memory used to dwell in the past, it
also helps formulate the present and the future.