'The light of memory, or rather the light that 'memory' lends to things, is the palest light of all
I am not quite sure whether I am dreaming, or remembering, whether I have lived my life, or dreamed it
Just as dreams do, 'memory' makes me profoundly aware of the unrealit - the evanescence of the world - a fleeting image in moving water'
Eugène Ionesco
The popular image of memory is as a kind of tiny filing cabinet, full of individual memory folders in which information is stored away, or perhaps as a neural super-computer of huge capacity and speed, however, in the light of modern biological and psychological knowledge, these metaphors may not be entirely useful and today, experts, (like Dr. Brandt - in our story), believe that memory is in fact far more complex and subtle than that.
It seems that our memory is located not in one particular place in the brain, but is instead a brain-wide process in which several different areas of the brain act in conjunction with one another (sometimes referred to as 'distributed processing').
For example, the simple act of riding a bike is actively and seamlessly reconstructed by the brain from many different areas: the memory of how to operate the bike comes from one area, the memory of how to get from here to the end of the block comes from another, the memory of biking safety rules from another, and that nervous feeling when a car veers dangerously close comes from still another.
Each element of a memory (sights, sounds, words, emotions) is encoded in the same part of the brain that originally created that fragment (visual cortex, motor cortex, language area, etc), and recall of a memory effectively re-activates the neural patterns generated during the original encoding.
Thus, a better image might be that of a complex web, in which the threads symbolize the various elements of a memory, that join at nodes or intersection points to form a whole rounded memory of a person, object or event.
This kind of 'distributed memory' ensures that even if part of the brain is damaged, some parts of an experience may still remain.
Neither is memory a single unitary process, but rather there are different types of memory.
Our 'short term' and 'long-term' memories are encoded and stored in different ways and in different parts of the brain, for reasons that are not entirely understood.
Years of case studies of patients suffering from accidents and brain-related diseases, and other disorders have begun to indicate some of the complexities of the memory processes, but many of the exact mechanisms involved remain elusive.
Episodic Memory
Episodic is particularly relevant in the case of 'Jim', as describe in our story.
Episodic memory is the memory of autobiographical events (times, places, associated emotions, and other contextual who, what, when, where, why knowledge), that can be explicitly stated or conjured.
It is the collection of past personal experiences that occurred at a particular time and place.
For example, if one remembers the party on his or her 6th birthday, this is an episodic memory.
They allow an individual to figuratively travel back in time to remember the event that took place at that particular time and place.
Semantic and episodic memory together make up the category of declarative memory, which is one of the two major divisions of memory - the other is implicit memory.
The term 'episodic memory' was coined by Tulving in 1972.
He was referring to the distinction between knowing and remembering.
Knowing is more factual (semantic), whereas remembering is a feeling that is located in the past (episodic).
Tulving has essentially defined three key properties of episodic memory recollection.
These are a subjective sense of time (or mental time travel), connection to the self, and autonoetic consciousness.
Autonoetic consciousness refers to a special kind of consciousness that accompanies the act of remembering, which enables an individual to be aware of the self in a subjective time.
There are other important aspects of recollection, which includes visual imagery, narrative structure, retrieval of semantic information, and the feelings of familiarity.
Events that are recorded into episodic memory may trigger episodic learning, i.e. a change in behaviour that occurs as a result of an event.
For example, a fear of dogs after being bitten by a dog is a result of episodic learning.
One of the main components of episodic memory is the process of recollection.
Recollection is a process that elicits the retrieval of contextual information pertaining to a specific event or experience that has occurred.
Autobiographical Memory
An autobiographical memory is a personal representation of general or specific events and personal facts.
Autobiographical memory also refers to memory of a person's history.
It is suggested that an individual does not remember exactly everything that has happened in one's past.
Memory is constructive, where previous experience affects how we remember events, and what we end up recalling from memory.
Autobiographical memory is constructive, and reconstructed as an evolving process of history.
A person's autobiographical memory is fairly reliable; although, the reliability of autobiographical memories is questionable because of memory distortions.
Autobiographical memories can differ for special periods of life.
People usually recall few personal events from the first years of their lives, (why ?).
The loss of these first events is called childhood or infantile amnesia.
People tend to recall many personal events from adolescence and early adulthood.
This effect is called the reminiscence bump.
Additionally, people recall many personal events from their previous few years.
For adolescents and young adults the 'reminiscence bump' and the recent events can coincide.
It is known that autobiographical memories initially are stored as episodic memories (see above,), but it is currently unknown if autobiographical memories are the same as episodic memories or if the autobiographical memories become converted to semantic memories with time.
Memory and Emotion
The relationship between emotion and memory is complex, but generally, emotion tends to increase the likelihood that an event will be remembered later, and that it will be remembered vividly. 'Flashbulb' memory is one example of this.
An example of this would be an experience such as a close family member dying, or the Christmas that you got the exact toy you wanted as a kid.
The experience holds so much emotional significance that it is encoded as an extremely vivid, almost picture-perfect memory.
Whether the vividness of the 'flashbulb' memory is due to a virtual "flash" that occurs because of the emotional experience has, however, been hotly contested.
'Flashbulb' memories may occur because of our propensity to rehearse and retell those highly emotional events, - a phenomena which probably strengthens the memory.
Flashbulb Memories
Flashbulb memories are one type of autobiographical memory (see above).
Some researchers believe that there is reason to distinguish flashbulb memories from other types of autobiographical memory because they rely on elements of personal importance, consequentiality, emotion, and surprise.
Others believe that ordinary memories can also be accurate and long-lasting if they are highly distinctive, personally significant, or repeatedly rehearsed.
Flashbulb memories have six characteristic features: place, ongoing activity, informant, own effect, other effect, and aftermath.
Arguably, the principal determinants of a flashbulb memory are a high level of surprise, a high level of consequentiality, and perhaps emotional arousal.
Brown and Kulik, who coined the term flashbulb memories, believed that although flashbulb memories are permanent, they are not always accessible from long term memory.
The hypothesis of a special flashbulb-memory mechanism holds that flashbulb memories have special characteristics that are different from those produced by "ordinary" memory mechanisms.
The representations created by the special mechanism are detailed, accurate, vivid, and resistant to forgetting.
Most of these initial properties of flashbulb memories have been debated since Brown and Kulik first coined the term.
It is possible for both positive and negative events to produce flashbulb memories.
When the event is viewed as a positive event, individuals show higher rates of reliving and sensory imagery, also showed having more live-qualities associated with the event.
Individuals view these positive events as central to their identities and life stories, resulting in more rehearsal of the event, encoding the memory with more subjective clarity.
Compared to positive flashbulb memories, events seen as negative by a person are more highly unpleasant, causing a person to avoid reliving the negative event.
This avoidance could possibly lead to a reduction of emotional intensity of the memory.
Such memories stay intact in an individual who experiences a negative flashbulb memory, but have a more toned down emotional side.
In general, younger adults form flashbulb memories more readily than older adults.
Memory Damage
Based on a review of behavioural studies, it has been suggested that there may be selective damage to the limbic-pre-frontal episodic memory system in some people with autism, and undoubtedly Dr. Brandt will be considering if 'Jim' exhibits any symptoms of Autism, or Aperger's Syndrome.
Other studies point to evidence of autistic deficits in the episodic or self-conscious memory of personally experienced events.
The label 'amnesia', as we have seen in Dr. Brandt's diagnosis of 'Jim', is most often given to patients with deficits in episodic memory.
Amnesia is partial or complete loss of memory that goes beyond mere forgetting.
Often it is temporary and involves only part of a person's experience.
Amnesia is often caused by psychological trauma.
For a memory to become permanent (consolidated), there must be a persistent change in the strength of connections between particular neurons in the brain.
Retrograde amnesia can result either from damage to the site of memory storage or from a disruption in the mechanisms by which memories can be retrieved from their stores.
Many specific types of amnesia are recognized, including
A fugue state, formally 'dissociative fugue', is a rare condition precipitated by a stressful episode.
It is characterized by episode(s) of travelling away from home, and creating a new identity.
The form of amnesia that is linked with recovered memories is 'dissociative amnesia' (formerly known as psychogenic amnesia).
This results from a psychological cause, not by direct damage to the brain, and is a loss of memory of significant personal information, usually about traumatic or extremely stressful events.
Usually this is seen as a gap or gaps in recall for aspects of someone's life history, but with severe acute trauma, there can be a sudden acute onset of symptoms.
Global memory impairment makes it difficult for subjects to construct an accurate account of their present and past history.
The combination of lack of autobiographical memory and continued dissociation is likely to make these individuals vulnerable to suggestion, and to the construction of explanations for their trauma-related affects that may bear little relationship to the actual realities of their lives.
Repressed Memories
Repressed memories are memories that have been unconsciously blocked due to the memory being associated with a high level of stress or trauma.
The theory postulates that even though the individual cannot recall the memory, it may still be affecting them consciously, and that these memories can emerge later into the consciousness.
Ideas on repressed memory hiding trauma from awareness were an important part of Sigmund Freud's early work on psychoanalysis.
The existence of repressed memories is a somewhat controversial topic in psychology; although studies have concluded that it does occur in a varying percentage of victims of trauma.
Most psychologists support the theory of repressed memories, and suggest that repressed memories can be recovered through therapy.
Some psychologists, however, argue that can be a process through which false memories are created by blending actual memories and outside influences - a problem that Dr. Brandt has already raised with Dr. Lockwood, with regard to the treatment of 'Jim'.
The term 'repressed memory' is sometimes connected with the term 'dissociative amnesia' (Dr Brandt's 'working diagnosis' for 'Jim'), which is defined in the DSM-V as an 'inability to recall autobiographical information. This amnesia may be localized (i.e., an event or period of time), selective (i.e., a specific aspect of an event), or generalized (i.e., identity and life history).'
Research shows that traumatic memories are retrieved, at least at first, in the form of mental imprints that are dissociated.
These imprints are of the affective (emotional) and sensory elements of the traumatic experience. Those effected report the slow emergence of a personal narrative that can be considered explicit (conscious) memory.
The level of emotional significance of a memory correlates directly with the memory's veracity (truthfulness).
Studies of subjective reports of memory show that memories of highly significant events are unusually accurate and stable over time.
The imprints of traumatic experiences appear to be qualitatively different from those of non-traumatic events.
Traumatic memories may be coded differently from ordinary event memories, possibly because of alterations in attentional focusing, or the fact that extreme emotional arousal interferes with certain memory functions.
Another possibility is that traumatic events are pushed out of consciousness until a later events elicits or triggers a psychological response.
Support for this idea has come from studies in which trauma was temporarily induced.
There has also, however, been questioning regarding the reliability of some repressed memories.
Causes of Repression
It is hypothesised that repression may be one method used by individuals to cope with traumatic memories, by pushing them out of awareness (perhaps as an adaptation via psychogenic amnesia).
Researchers have proposed that repression can operate on a social level as well.
Psychogenic amnesia, now renamed 'dissociative amnesia', is found to increase in incidence after psychologically traumatic events such as war and natural disaster, which is consistent with the repression hypothesis.
Other theoretical causes of forgotten memories have stemmed from the idea of Retrieval-Influenced Forgetting, which states that apparently 'false' memories will be more accurately recalled when rehearsed more, than when actual memories get rehearsed.
In this scenario, the action of rehearsing a 'falsified' memory can actually take precedence over the actual memory that a person experiences.
It has also been discovered that rehearsal of novel information exhibits inhibitive processes on one’s ability to remember or recall the prior genuine memory.
This conclusion indicates that past memories can be easily forgotten, simply by attending to 'real', novel memories that are brought into awareness......
Autobiographical Memory
An autobiographical memory is a personal representation of general or specific events and personal facts.
Autobiographical memory also refers to memory of a person's history.
It is suggested that an individual does not remember exactly everything that has happened in one's past.
Memory is constructive, where previous experience affects how we remember events, and what we end up recalling from memory.
Autobiographical memory is constructive, and reconstructed as an evolving process of history.
A person's autobiographical memory is fairly reliable; although, the reliability of autobiographical memories is questionable because of memory distortions.
Autobiographical memories can differ for special periods of life.
People usually recall few personal events from the first years of their lives, (why ?).
The loss of these first events is called childhood or infantile amnesia.
People tend to recall many personal events from adolescence and early adulthood.
This effect is called the reminiscence bump.
Additionally, people recall many personal events from their previous few years.
For adolescents and young adults the 'reminiscence bump' and the recent events can coincide.
It is known that autobiographical memories initially are stored as episodic memories (see above,), but it is currently unknown if autobiographical memories are the same as episodic memories or if the autobiographical memories become converted to semantic memories with time.
Memory and Emotion
The relationship between emotion and memory is complex, but generally, emotion tends to increase the likelihood that an event will be remembered later, and that it will be remembered vividly. 'Flashbulb' memory is one example of this.
An example of this would be an experience such as a close family member dying, or the Christmas that you got the exact toy you wanted as a kid.
The experience holds so much emotional significance that it is encoded as an extremely vivid, almost picture-perfect memory.
Whether the vividness of the 'flashbulb' memory is due to a virtual "flash" that occurs because of the emotional experience has, however, been hotly contested.
'Flashbulb' memories may occur because of our propensity to rehearse and retell those highly emotional events, - a phenomena which probably strengthens the memory.
Flashbulb Memories
Flashbulb memories are one type of autobiographical memory (see above).
Some researchers believe that there is reason to distinguish flashbulb memories from other types of autobiographical memory because they rely on elements of personal importance, consequentiality, emotion, and surprise.
Others believe that ordinary memories can also be accurate and long-lasting if they are highly distinctive, personally significant, or repeatedly rehearsed.
Flashbulb memories have six characteristic features: place, ongoing activity, informant, own effect, other effect, and aftermath.
Arguably, the principal determinants of a flashbulb memory are a high level of surprise, a high level of consequentiality, and perhaps emotional arousal.
Brown and Kulik, who coined the term flashbulb memories, believed that although flashbulb memories are permanent, they are not always accessible from long term memory.
The hypothesis of a special flashbulb-memory mechanism holds that flashbulb memories have special characteristics that are different from those produced by "ordinary" memory mechanisms.
The representations created by the special mechanism are detailed, accurate, vivid, and resistant to forgetting.
Most of these initial properties of flashbulb memories have been debated since Brown and Kulik first coined the term.
It is possible for both positive and negative events to produce flashbulb memories.
When the event is viewed as a positive event, individuals show higher rates of reliving and sensory imagery, also showed having more live-qualities associated with the event.
Individuals view these positive events as central to their identities and life stories, resulting in more rehearsal of the event, encoding the memory with more subjective clarity.
Compared to positive flashbulb memories, events seen as negative by a person are more highly unpleasant, causing a person to avoid reliving the negative event.
This avoidance could possibly lead to a reduction of emotional intensity of the memory.
Such memories stay intact in an individual who experiences a negative flashbulb memory, but have a more toned down emotional side.
In general, younger adults form flashbulb memories more readily than older adults.
Memory Damage
Based on a review of behavioural studies, it has been suggested that there may be selective damage to the limbic-pre-frontal episodic memory system in some people with autism, and undoubtedly Dr. Brandt will be considering if 'Jim' exhibits any symptoms of Autism, or Aperger's Syndrome.
Other studies point to evidence of autistic deficits in the episodic or self-conscious memory of personally experienced events.
The label 'amnesia', as we have seen in Dr. Brandt's diagnosis of 'Jim', is most often given to patients with deficits in episodic memory.
Amnesia is partial or complete loss of memory that goes beyond mere forgetting.
Often it is temporary and involves only part of a person's experience.
Amnesia is often caused by psychological trauma.
For a memory to become permanent (consolidated), there must be a persistent change in the strength of connections between particular neurons in the brain.
Retrograde amnesia can result either from damage to the site of memory storage or from a disruption in the mechanisms by which memories can be retrieved from their stores.
Many specific types of amnesia are recognized, including
A fugue state, formally 'dissociative fugue', is a rare condition precipitated by a stressful episode.
It is characterized by episode(s) of travelling away from home, and creating a new identity.
The form of amnesia that is linked with recovered memories is 'dissociative amnesia' (formerly known as psychogenic amnesia).
This results from a psychological cause, not by direct damage to the brain, and is a loss of memory of significant personal information, usually about traumatic or extremely stressful events.
Usually this is seen as a gap or gaps in recall for aspects of someone's life history, but with severe acute trauma, there can be a sudden acute onset of symptoms.
Global memory impairment makes it difficult for subjects to construct an accurate account of their present and past history.
The combination of lack of autobiographical memory and continued dissociation is likely to make these individuals vulnerable to suggestion, and to the construction of explanations for their trauma-related affects that may bear little relationship to the actual realities of their lives.
Repressed Memories
Repressed memories are memories that have been unconsciously blocked due to the memory being associated with a high level of stress or trauma.
The theory postulates that even though the individual cannot recall the memory, it may still be affecting them consciously, and that these memories can emerge later into the consciousness.
Ideas on repressed memory hiding trauma from awareness were an important part of Sigmund Freud's early work on psychoanalysis.
The existence of repressed memories is a somewhat controversial topic in psychology; although studies have concluded that it does occur in a varying percentage of victims of trauma.
Most psychologists support the theory of repressed memories, and suggest that repressed memories can be recovered through therapy.
Some psychologists, however, argue that can be a process through which false memories are created by blending actual memories and outside influences - a problem that Dr. Brandt has already raised with Dr. Lockwood, with regard to the treatment of 'Jim'.
The term 'repressed memory' is sometimes connected with the term 'dissociative amnesia' (Dr Brandt's 'working diagnosis' for 'Jim'), which is defined in the DSM-V as an 'inability to recall autobiographical information. This amnesia may be localized (i.e., an event or period of time), selective (i.e., a specific aspect of an event), or generalized (i.e., identity and life history).'
Research shows that traumatic memories are retrieved, at least at first, in the form of mental imprints that are dissociated.
These imprints are of the affective (emotional) and sensory elements of the traumatic experience. Those effected report the slow emergence of a personal narrative that can be considered explicit (conscious) memory.
The level of emotional significance of a memory correlates directly with the memory's veracity (truthfulness).
Studies of subjective reports of memory show that memories of highly significant events are unusually accurate and stable over time.
The imprints of traumatic experiences appear to be qualitatively different from those of non-traumatic events.
Traumatic memories may be coded differently from ordinary event memories, possibly because of alterations in attentional focusing, or the fact that extreme emotional arousal interferes with certain memory functions.
Another possibility is that traumatic events are pushed out of consciousness until a later events elicits or triggers a psychological response.
Support for this idea has come from studies in which trauma was temporarily induced.
There has also, however, been questioning regarding the reliability of some repressed memories.
Causes of Repression
It is hypothesised that repression may be one method used by individuals to cope with traumatic memories, by pushing them out of awareness (perhaps as an adaptation via psychogenic amnesia).
Researchers have proposed that repression can operate on a social level as well.
Psychogenic amnesia, now renamed 'dissociative amnesia', is found to increase in incidence after psychologically traumatic events such as war and natural disaster, which is consistent with the repression hypothesis.
Other theoretical causes of forgotten memories have stemmed from the idea of Retrieval-Influenced Forgetting, which states that apparently 'false' memories will be more accurately recalled when rehearsed more, than when actual memories get rehearsed.
In this scenario, the action of rehearsing a 'falsified' memory can actually take precedence over the actual memory that a person experiences.
It has also been discovered that rehearsal of novel information exhibits inhibitive processes on one’s ability to remember or recall the prior genuine memory.
This conclusion indicates that past memories can be easily forgotten, simply by attending to 'real', novel memories that are brought into awareness......
this is an additional article for your further enjoyment of
No comments:
Post a Comment