Differences in Short-Term and Long-Term Memory - Essay Example

Short-term and Long-Term Memory This essay paper surveys several articles that provide details on the studies discussing the evidence and arguments pertaining to the issue of whether or not remembering over the short- and long-term necessitate the assumption that there are distinct systems supporting storage and retrieval processes over these different timescales. These articles recommend that there should be critical studies on all forms of memory in order to fully understand their differences. The exhaustive research efforts on whether or not remembering over the short term memory and long term memory are operated by distinct systems, has generated several important concepts towards the understanding of these different timescales. Keywords: Short term memory, long term memory, storage, retrieval processes. Long term memory is a record of past events and an enormous store of knowledge. The information in the long term memory is mostly outside our awareness, nonetheless, may be recalled into working memory when required. Short-term memory (primary or active memory) is the ability to hold a trivial amount of information in the human mind in an active, readily accessible form for a small period of time. Information from short term memory arises from being attentive to sensory memories. The classic difference between short term memory and long term memory has remained a principal feature of all key information-processing models of memory (Ranganath and Blumenfeld, 2005). Storage in human memory is among the 3 core process of memory, along with encoding and recall. It denotes the retention of information that has been attained via the encoding process, in the brain for a long time till it is retrieved via recall. Current memory psychology distinguishes the 2 distinct kind of memory storage: long term memory and short term memory. Additionally, various memory models have proposed variations of existing long-term memory and short-term to account for various ways of storing memory (Baddeley, Eysenck, & Anderson, 2009). To carry out complex cognitive activities, individuals must maintain access to enormous amounts of information. For instance, a person reading a sentence in a text needs access to earlier mentioned objects and actors so as to solve references to pronouns. The person also requires contextual information in order to assimilate coherent information posed in the present sentence with the text earlier read(Baddeley, 1990). Cognitive processes may be defined as a sequence of thoughts or states. Memory intermediates amid the states of this sequence. Cognitive states are reliant on each other, and memory and environmental correlations produce this dependency. Thoughts (which are the cognitive states) are the outcomes of intricate generation processes(Baddeley, 1990). As per Baddeley’s model, there are distinct buffers for various kinds of information. These buffers, consecutively, are separate from long term memory. The phonological loop (a verbal buffer) is presumed to hold information which may be rehearsed verbally (for example, digits and letters). A visuospatial sketchpad is presumed to sustain visual information and may be further broken down into spatial stores and visual/object (Repov and Baddeley 2006). An episodic buffer, which draws on the other buffers and long term memory, has been added to justify the retaining of multimodal information (Baddeley, 2000). Besides the storage buffers defined above, a central executive is suggested to organize the relationship between the different buffers and long term memory and is concerned with controlled processing. In summary, the multi-store model consists of numerous distinctions: Short term memory is distinct from long term memory; short term memory may be stratified into various informational buffers on the basis of type of information; and storage and executive procedures are different in the two memories. Proof in support of these assertions has depended on neuroimaging data, neuropsychological studies, and on behavioural interference studies. Some chief contentions with regard to the distinctions between the two memory types are: short term memory entails ‘activity’ traces, whilst long term memory entails ‘structural’ traces (Burgess and Hitch, 2006); short term memory entails autonomous decay, whilst short term memory entails irreversible, non-decaying traces (Burgess and Hitch, 2006); and short term memory has a fixed capacity which is prone to overload and resultant loss of stored elements, for non-associative reasons, whilst long term memory is, basically, unlimitedly expansible, with failure of retrieval accredited chiefly to incompleteness of the signal to retrieval or to interference from subsequently or previously learned associations (Jonides and Nee, 2006). Research on brain-injured individuals who demonstrate a deficit in the short term memory but not long term memory or vice versa resulted in the implication that short term memory and long term memory are distinct systems. Individuals with temporal lobe and parietal lobe damage demonstrated altered short-term, phonological abilities but unharmed long term memory (Repov and Baddeley, 2006). On the contrary, it is usually claimed that individuals with MTL (medial temporal lobe) damage illustrate impaired long term memory but preserved short term memory (Baddeley, 2003). Neuroimaging information from healthy individuals has yielded mixed outcomes. Conversely, a meta-analysis comparing areas stimulated during verbal long term memory and short term memory activities demonstrated a huge deal of overlap in neural stimulation for the tasks in the parietal lobe and frontal lobe (Cabeza, Dolcos, Graham, and Nyberg, 2002). Three studies, which directly compared long term memory and short term memory in the same individuals did demonstrate some areas selective for each one of the memory system (Cabeza, Dolcos, Graham, and Nyberg, 2002;Talmi, Grady, Goshen-Gottstein and Moscovitch, 2005). However, of these researches, only one found that the medial temporal lobe was uniquely stimulated for long term memory (Talmi, Grady, Goshen-Gottstein and Moscovitch, 2005). One possibility of the reason behind the discrepancy between the neuroimaging and neuropsychological data is that neuroimaging tasks of short term memory usually use longer retention intervals in comparison to those employed for neuropsychological activities, making the short memory tasks more similar to long term memory tasks. Numerous studies have demonstrated that the medial temporal lobe is significant when retention intervals are more than a few seconds (Cabeza, Dolcos, Graham, and Nyberg, 2002; Buffalo, Reber and Squire, 1998). Of the researches, which compared short term memory, and long term memory in the same individuals, only Talmi, Grady, Goshen-Gottstein and Moscovitch (2005) used a short term memory retention interval less than 5 seconds. This research did find, indeed that the medial temporal lobe was distinctively recruited at elongated retention intervals, giving support for the previous neuropsychological study dissociating long term memory and short term memory. The idea that short term memory could be parcelled into information-precise buffers initially received support from a series of researches on selective interference (Jonidesand Nee, 2006). These investigations depended on the logic that if 2 tasks apply the same processing mechanisms, they ought to illustrate interfering effects on one another if carried out simultaneously. This work demonstrated a double dissociation: Verbal activities interfered with verbal short term memory but not visual short term memory. Visual activities interfered with visual short term memory as opposed to verbal short term memory, giving support to the notion of distinguishable memory systems (Baddeley, 2003). The introduction of neuroimaging has permitted researchers to examine the neural correlates of the alleged separability of short term memory buffers. Verbal short term memory has been demonstrated to depend principally on left parietal cortices and left inferior frontal, spatial short term memory on right parietal and right posterior dorsal frontal cortices, and object/visual short term memory on left inferior temporal, left parietal, and left inferior frontal cortices (Jonidesand Nee, 2006). Verbal short term memory demonstrates a marked left hemisphere preference while spatial and object short term memory may be distinguished largely by the separation of the dorsal versus ventral in posterior cortices (Baddeley, 2003). The most recent proposed episodic buffer stemmed from the need to explain for interactions between short memory term buffers and long term memory. For instance, the number of words recalled in a short term memory experiment may be significantly increased if the words create a sentence (Baddeley, 2003). The ‘chunking’ together of words so as to increase short term capability depends on additional information from long term memory which may be applied to assimilate the words (Baddeley, 2000). Therefore, there ought to be some representational space which permits for the integration of stored information in the phonological loop and long term memory. This capability to integrate information from short term memory and long term memory is somewhat preserved despite one of these memory systems being impaired (Baddeley, 2000; Baddeley, 2003). These results give support for an episodic buffer which is distinguishable from other short term buffers and from long term memory (Baddeley, 2000, Baddeley, 2003). Even though, neural evidence on the probable localization of this buffer is slim, there is some recommendation that dorsolateral prefrontal cortex is involved (Zhang et al., 2004). Selective retrieval could best be investigated with cued recall. In cued recall activities, individuals retrieve an object in reaction to a retrieval cue offered by the experimenter. Retrieval from short term memory is often elicited by the experimenter displaying to the individual a list of objects and later asking the individual to name the object that followed a given object in the list. Sternberg (1969) demonstrated that retrieval time was a linear function of the length of the list. This outcome suggests a search rate of two hundred and fifty milliseconds per object, which is nearly 10 times slower than the rate evaluated for recognition. Numerous investigators (Wheeler et al. 2006; Wager and Smith, 2003) have acquired similar estimations for retrieval from short term memory. Wager and Smith (2003) observed that the search rates are close to the internal speech speed. As per chunking theory not all information on the chunks is stored in the short term memory. Instead, a retrieval cue or a general pointer is stored in the short term memory that permits the individuals at the time of recall to retrieve information from the chunk in the long term memory. The duration it takes to retrieve information stored in the long term memory is in general projected from the difference between recognition times for objects previously stored in the long term memory and for just observed objects which are retained in active form in the short term memory. Sternberg (1969) noted that recognition times for greatly practiced lists stored in the long term memory were two hundred milliseconds to four hundred milliseconds longer than those for items stored in the short term memory, dependent on the length of the list (up to 5items long). For meaningful items, for instance, sentences, storage in the long term memory takes place usually subsequent to a single presentation. In recognition tests of sentences, retrieval of sentences stored in the long term memory takes, to some degree, longer than it does for just observed sentences stored in the short term memory. An additional four hundred and twenty milliseconds is needed for sentences which are stored after a single presentation. For sentences examined at 2 different times, the projected retrieval time is decreased to two hundred and eighty milliseconds (Anderson et al, 2004). The difference between short term memory and long term memory relies on whether it can be illustrated that there are properties specific to long term memory in comparison to short term memory. In conclusion, with the representational bases for perception, short term memory, and long term memory are indistinguishable. Namely, similar neural representations primarily stimulated during the encoding of a piece of information demonstrate sustained stimulation during short term memory (or retrieval from long term memory into short term memory) and are the origin of long term representations (Wheeler et al. 2006). Since areas of neocortex represent various sorts of information (for instance, spatial and verbal), it is also rational to expect that short term memory will possess an organization by type of material. Functionally, short term memory seems to compose of objects in the focus of attention alongside with freshly attended representations in the long term memory. These objects in the focus of attention number no more than 4, and they could be restricted to just a single representation (comprising of objects bound in a functional context). Reference List Anderson J, Bothell D, Byrne M, Douglass S, Lebiere C, Qin Y. (2004). An integrated theory of mind. Psychol. Rev. 111:1036–60 Baddeley A. (1990). 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