ExplainingShort and Long Term Memory
Memoryis the term given to process and structures pertaining the storageand subsequent retrieval of information. Therefore, it is a crucialcomponent of daily activities. First, the information enters in theshort-term memory for encoding. When a person learns new things, thenewly acquired information is changed into a format appropriate forstorage in the brain (Howard 8). The memory has a limited capacityalthough the amount and duration of information mainly vary dependingon the type of material. According to experiments, most adults canhold approximately seven items in the short-term memory at any giventime. The human brain acquires and processes the information insequences, and the same process is used for the retrieval process.Usually, information lasts between twenty to thirty seconds in theshort-term section (Vallar and Shallice 7).
Subsequently,the information is transferred to the long-term memory for storage.In this section, it can be stored for as long as necessary to beretrieved on request (Doyle-Portillo and Pastorino 235). Similarinformation is linked together, and the association is used whenretrieving it. Despite the apparent differences between the short andlong-term memories, the two areas are affected by brain injury in asimilar way. Brain injury damages the axons that transmit electricaland visual messages throughout the brain. Thus, an individual withbrain injury has a problem acquiring new knowledge in the short-termmemory. It means that the brain does not have any new information tosend to the long-term memory.
Inaddition, it can result in amnesia where an individual forgets theinformation of the past event. In most cases, people forget therecently acquired knowledge while the childhood memories remainintact. Amnesia can be retrograde, post-traumatic, and anterogradedepending on the type of injury or disease. A person suffering fromamnesia may use false information to fill in the spaces of missinginformation (Doyle-Portillo and Pastorino 237). However, such actionsare not necessarily aimed to deceive intentionally because an amnesicperson believes the information to involve real events. Therefore,understanding perceived and actual stimuli is important in varioussectors such as the courts. The judge and jury have to assess if aperson’s memories can be trusted by evaluating if they contain anymisinformation. Nonetheless, with proper treatments and care it ispossible to recover most of the lost memories.
Thehuman brain allows for collection, storage, and retrieval of materialin the form of memories. It has different types of memory, which arestored in distinctive parts of the brain and for a varied duration.Thus, memory affects an individual’s capability of learning newthings. In the past, experts described memory as a sort of tinyfiling cabinet with separate memory sections in which information isstored. Others compared memory to a neural supercomputer compressedunder the scalp. However, today experts believe that the mind is muchmore intricate than that and that it is a brain-wide process asopposed to being located in one particular place (Howard 10). Thus,the mind produces a substantial thought through a complexconstruction process that goes through different sections of thebrain to create short-term and long-term memories. These types ofmemory have a particular system of operation, but they work togetherin the process of memorization to form a lasting memory. On a largedegree, the human senses depend upon what a person learns, knows andthe ability to remember the learned information (Howard 11).
Althoughthe short and long-term memories interact to have a successful memoryprocess, they are unique in their abilities. Accordingly, it ispossible to understand the structure and organization of the humanmind by studying the amnesic disorder associated with a brain injurybecause it affects the two memory stores in different ways.
Thestructure and functions of the short-term memory
Theshort-term memory is the information a person can remember shortlyafter acquiring it. Besides, it contains the material a person isworking on currently (Vallar and Shallice 6). Therefore, it is asystem used to store information temporarily, which is required tocarry out intricate cognitive tasks such as comprehension, learning,and reasoning. It can also initiate, select, and terminateinformation processing functions such as data translation, storage,and retrieval. The information in the short-term memory arises whensomeone pays attention to the sensory memories. They are stored forapproximately twenty to thirty seconds. However, this process canalso take just a few seconds if there are events preventing activemaintenance of the information. Furthermore, the volume ofinformation stored in the short-term section is also varied (Vallarand Shallice 7). Based on experiments, experts indicate that theshort-term memory stores approximately seven items. Nevertheless,they can be more or less depending on the type of information. Mostof the time, the newly acquired information displaces limitedcapacity of the short-term memory to create more space. Therefore, anindividual has to give additional focus to information if he or shewishes for it to remain in the short-term memory for longer (Howard63). However, it is impossible to focus on a single item for long,which means that information in the short-term memory is naturallydisplaced mainly due to external factors. The short-term memories arestored and retrieved sequentially. For example, a person listens to alist of items and then he has to recall the fifth item. First, herecalls the first four items in order to retrieve the information ofthe fifth item.
Theshort-term memory is a necessary step towards retaining informationin the long-term memory. A person’s ability to hold informationbriefly in order to complete a task causes the pre-frontal lobe inthe brain to become very active. The central executive region of theprefrontal cortex serves as both a temporary storage for informationand recalls data in other parts of the brain (Rainer and Windhorst374). The central executive regulates two neural loops for languageand visual data. When the mind forgets the information in theshort-term memory, it means that the nerve impulse can no longerspread through a particular neural network. Moreover, outsideinterference causes disturbances in the short-term memory, whichinterferes with memory retention. As such, people have a desire tofinish the tasks associated with information held in the short-termmemory as soon as possible. Nevertheless, despite the limitedcapacity, the short-term memory is relatively unaffected by the speedof presenting the information.
Thestructure and functions of the long-term memory
Thelong-term memory is the continuous storage of information in thebrain. It receives information from the short-term section throughthe hippocampus, which is located in the inner part of the temporallobe. The hippocampus is a fundamental brain structure thatfacilitates proper functioning of the long-term memory. In addition,the brain has neural pathways that connect the hippocampus andcortical structures surrounding it to the cortex (Doyle-Portillo andPastorino 235). The region is mainly involved in maintaining thedeclarative memory. Thus, the hippocampus plays an essential role inepisodic memory by enabling the brain to recall the information byreactivating the particular activity pattern in various regions ofthe cortex. Nevertheless, the hippocampus is not necessarily requiredwhen remembering encoded information in this memory section for along time. The similar case happens when retrieving general knowledgein the semantic memory, which instead activates the temporal andfrontal cortexes.
Thelong-term section usually stores both unconscious and preconsciousinformation (Doyle-Portillo and Pastorino 235). Hence, it is largelyoutside an individual’s consciousness, but it can be recalled intoworking memory when necessary. Some information is easy to rememberdepending on the type of information and the duration that has passedsince it was stored. Although it is also vulnerable to the forgettingprocess, the memory can be recalled after a day, weeks or even years(Doyle-Portillo and Pastorino 236). Nonetheless, the memories differwhen remembering. For instance, it is possible to remember anoccasion or details of stronger memory on demand while an individualhas to promote the brain to recall the weaker details. The long-termmemory has two sections: the declarative and procedural recollection.The declarative memory contains all the information available inconsciousness, which contains semantic and episodic memories(Doyle-Portillo and Pastorino 238). On the other hand, the brainunconsciously remembers the procedural memories entailing bodymovement and using the objects in the surrounding. The brain conductsa regular revision of these memories and it merges them with othermaterials or including what other people’s views of therecollection (Doyle-Portillo and Pastorino 237). As a result,memories are not always constant thus, sometimes they areunreliable.
Thelong-term memory has a large capacity for storing information but hasa relatively slow speed of acquiring new information. Besides, itencodes verbal information through meaning rather than sound. Thememories are stored by linking similar information together.Organizing the information in the long-term memory is crucial becauseit helps in the retrieval process. Similarly, the long-term memory isalso prone to distractions by other events, which will lower thequality of information as it passes from the short-term memory(Doyle-Portillo and Pastorino 238). For example, a witness at a crimescene may present unreliable information because the upsetting eventsmay have distracted his or her memories. In such a case, anindividual’s focus is mainly on the weapons, which diminishes theirability to perceive other information. Thus, the brain is also proneto false memories in such cases. That is why, it is important tochange the perspective of the issues to challenge a witness’stestimony to validate if their testimony is truthful as imperfectlyrecorded in the short-term memory. Consequently, a lawyer starts byquestioning the imperfections created in the short-term stage thatthe brain has fixed in the long-term memory.
Impactsof brain injury
Duringa brain injury, the chemical stability is changed. Swelling squeezesthe middle sections, which eventually pushes the brain down. Themiddle segment is also torn due to the back and front movement of thebrain during an accident. As the brain continues to deteriorate, itreaches a breaking point when loss of function becomes apparent.Brain damage mainly affects the axons nerve fibers. The axons are thethin elongated fiber that transmits vital chemical and electricalsignals to different regions of the brain. The nerve fiber is veryfragile and starts to disconnect after brain injury (Coetzer 14).Then, the blunt end of an axon closes itself up, which causes it toswell with fluids, proteins, enzymes and eventually bursts. As aresult, the axons spread amyloid proteins through the adjacent braintissue. The axons capability is inhibited, slowing down a person’sability to process new information. Some axons survive and counteractthe damage by increasing electrical signaling to restore normal speedfor the brain to process information. However, it is only a temporarysolution, which can cause the axons to be more sensitive tosubsequent brain damage.
Asa result, both short and long-term memories are prone to problemsassociated with a brain injury or traumatic experiences. Even with animpaired short-term memory, the brain can still recall an event thatoccurred a long time ago. However, it cannot remember the details ofsomething that happened a few minutes before (Coetzer 46). There aremany reasons that can cause short-term memory losses such as lack ofoxygen to the brain, alcohol and drug abuse, trauma, or concussions.After a brain injury, the short-term memory is affected, whichhinders the brain from processing the information accurately.Consequently, there is a problem when storing informationtemporarily. The long-term memory is also susceptible to braininjuries. Similarly, a person suffering from long-term memory losshas a problem trying to remember an event that took place a fewminutes ago. Due to the issues faced when trying to store short-termmemory, the brain is incapable of transferring any information to thelong-term memory, which can result in amnesia (Howard 60).
Typesand effects of amnesia on memory
Amnesiais the condition where stored memories are largely lost, or the brainis unable to store something to memory. It can result fromneurological, organic, functional, or psychogenic causes. Amnesiamainly occurs due to some damage to the hippocampus and surroundingareas of the brain. Thus, the brain can no longer encode, store orretrieve the memories (Rainer and Windhorst 368). Most people withamnesia have an impaired short-term memory where they cannot retainnew information. Nonetheless, amnesia is selective because it onlyextends to a portion of memory, and it does not affect all kinds oflearning. Hence, it does not affect an individual’s intelligence,awareness, personality, judgment, or general knowledge. As such,people with amnesia can learn new skills and understand both verbaland written words (Doyle-Portillo and Pastorino 263).
Peoplewith head injuries experience memory problems in the form ofanterograde and retrograde amnesia. Anterograde amnesia occurs whenthe brain does not recognize new things because it is renderedincapable of transferring information from the conscious short-termmemory to the permanent long-term memory. It erases the events thatoccur after a head injury (Rainer and Windhorst 368). On the otherhand, retrograde amnesia occurs when a person cannot remember theexisting memories beyond the average degree of forgetfulness. Inretrograde amnesia a person losses memories of events preceding thehead injury. Therefore, the short-term memory is incapable of storingnew information. The memory loss can be for just a few seconds orextend to a minute. However, it may affect longer periods for somepeople due to the magnitude of the injury. Nonetheless, a person canstill recognize new things if he or she acquired the informationafter the amnesia. Even in cases of memory loss, the brain preservesthe procedural memories that involve habits as opposed to thedeclarative memories concerning facts and events. In some cases, anindividual can suffer from the two types of amnesia resulting to astate called global amnesia.
Anothertype is the post-traumatic amnesia, which results in confusion andmemory loss after a traumatic brain injury. Posttraumatic amnesiaalso affects the short and long-term memories (Van der Kolk andFisler 507). A traumatic event disrupts the electrical activity ofthe brain and prevents the short-term memory from functioningproperly. Thus, it interferes with the information processing in theshort-term memory resulting in temporary episodes of amnesia. In mostcases, this amnesia lasts for a short while but the duration isvaried depending on the severity of the trauma. Its maincharacteristics are the inability to learn new things and impairedability to recall information from the past and previously familiarevents. Therefore, post-traumatic amnesia can result in false memory,which a person invents to replace the lost genuine memories. Thefalse memory arises in willing or well-intentioned witnesses causedby cognitive factors influencing someone’s ability to remember. Infalse memories, a person recalls what he or she experiences as havinghappened but not what occurred (Van der Kolk and Fisler 506). Theyare embedded in a person’s existing memories, and in most cases,they will believe that these materials are real. Mainly, fake memoryresults from misattribution and misinformation of the source ofinformation. In addition, a person can obtain false memoriesunintentionally through leading or misleading. The existing materialand other memories can also interfere with information of a newmemory. Hence, the information recalled in such a case is mistaken orfalse. As a result, eyewitness testimony can be extremely flawedbecause of the misleading effects of police interrogation, erroneouspress reports, and the format used when asking the questions duringthe trial.
Importanceof understanding the effects of amnesia
Althoughmemory for specific information varies according to an individual’sstate of mind, it can also be dependent on the content itself. Forexample, the brain tends to recall better the memory that results inan exciting feeling as opposed to the information from a traumaticexperience. Hence, a person may claim to remember some negativelyarousing information vividly, but he or she may have a problemdistinguishing between seen and imagined events in the short-termmemory and later transferred to long-term memory. Consequently, aperson suffering from post-traumatic amnesia is incapable ofrecalling the facts of the accident (Van der Kolk and Fisler 505). Inaddition, he or she portrays signs of anterograde amnesia ofirregular duration and occasionally temporary retrograde amnesia.Such a person is usually confused at the spatiotemporal level andsometimes even restless. They are unable to translate newinformation, have severe attention issues, and major impairments ofcontemplation and judgment.
Therefore,during the court cases, reality monitoring is important indistinguishing the real and imagined stimuli. Scrutinizing thewitness ensures that he is she is not suffering from source amnesia,which would result in the presentation of false memories. Forexample, a person may be present during a crime and required to givea testimony in court. However, before the case, the witness watchesnews detailing the events of the incident. During the hearing, theperson fills in some missing gaps in the information using thedetails they watched on the television (Van der Kolk and Fisler 506).Such a person is not deliberately lying, but they are unable toremember the origin of all the information. Nonetheless, it ispossible to recover from brain injury. As a person recovers, thelong-term memories tend to return. However, they do so in piecesrandomly.
Memoryis the vital cognitive process that supports learning and makes itpossible to acquire new knowledge and remember new information as aperson encounters different circumstances. The underlying memoryprocess takes place in stages from the short-term through to thelong-term memory. The short-term memory comprises of an individual’smomentary conscious perceptions and thoughts. The memory is briefwith the contents lasting only as long as a person is concentratingon them. In addition, it stores a limited amount of informationapproximately seven items simultaneously. Once the short-term memorycollects and encodes the information, it is transferred to thelong-term memory where it is stored for retrieval whenever necessary.The information stored in the long-term memory can be retrievedconsciously or unconsciously whenever needed. However, these twomemories are vulnerable to distractions from external factors such asbrain injury. When the brain is injured, the axons that transmitinformation are ruptured. Thus, they swell up with proteins andenzyme, which hinder their operations. Such a situation results inamnesia where a person has a problem acquiring and retaining newinformation in the short-term memory or retrieving information keptin the long-term memory. As a result, a person may fill these gaps ofinformation with false memories. False memories mainly entail mentalexperiences that are mistakably taken as real events that took placein a person’s past. These arise when a person can no longerremember information surrounding some events, and instead theyacquire false information of the events they believe to haveoccurred, but in reality, it did not. The situation is especiallycommon in cases of post-traumatic amnesia where people think thatthey can vividly remember information surrounding a traumatic event,but instead they are just giving distorted information of what theybelieve to be true. Thus, the understanding memory-related issuessuch as amnesia and brain injury are necessary for the court systembecause it helps in distinguishing between the perceived and realstimuli. The information is used to determine if a witness’smemories can be trusted to give the actual information surrounding aparticular event. Finally, experts are extensively studying theoperations of the human brain, effects of brain injury, and methodsto treat amnesia. As such, the experts are still researching andelaborating on the currently available information.
Coetzer,Rudi. TraumaticBrain Injury Rehabilitation: A Psychotherapeutic Approach to Loss andGrief.New York: Nova Science Publishers, Inc., 2006. Print.
Doyle-Portillo,Susann, and Ellen Pastorino. WhatIs Psychology? Belmont,Calif: Wadsworth, 2011. Print.
Howard,Robert W. Learningand Memory: Major Ideas, Principles, Issues, and Applications.Westport, Conn: Prager, 1995. Print.
Rainer,Greger and Uwe Windhorst.Ed.Comprehensive Human Physiology: From Cellular Mechanisms toIntegration.Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. Internetresource.
Vallar,Giuseppe and Tim Shallice. NeuropsychologicalImpairments of Short-Term Memory.Cambridge: Cambridge University Press, 2007. Print.
Vander Kolk, Bessel and Rita, Fisler. “Disassociation and thefragmentary nature of traumatic memories: Overview and exploratorystudy.” Journal of Traumatic Stress, 8 (1995): 505-525. Web. 8 May2015.