Human Memory Systems - Essay Example

?Human memory consists of systems used for storing and recalling information such as personal experiences, facts, emotions, procedures, skills and habits (Tulving 2006). Different scientific disciplines have examined various aspects of memory from diverse perspectives and as a result, the topic has been subject of intense debate and controversies. However, in spite of these attempts, there is no universally acceptable model of human memory. According to Christian et al (2000), classification of the multiple memory systems is one of the most challenging endeavors in the study of human memory. This paper examines the description of memory systems in human beings and the evidence of differentiation of memory. Neuropsychological perspective describes and classifies human memory systems using various methods. One of the approaches is classification by dissociation, where the evidence for the method is derived from clinical and experimental observations concerning the working or functioning of the memory (Tulving 2006). Using this approach, human memory consists of three interrelated subsystems namely short-term sensory storage (STSS), working or short-term memory (STM) and long-term memory (LTM). Short-term sensory storage system is fast and automatic system that stores information for a period of less than one second. The sensory system perceives and stores visual and auditory information temporarily (Tulving 2006). According to Baddeley (1997), dissociation contributes an important but insufficient condition for classifying tasks in various categories and making conclusions about memory systems and subsystems. However, credible evidence supporting the multiple memory systems have been provided by congruence of findings from experiments in neuropsychological, neurochemical and developmental studies. In context to short term and long-term memory systems, various experiments across different scientific fields have been conducted to establish their differences and the similar characteristics. The convergent element of these experiments indicate that short term and long term memories show distinct characteristics indicating that both are different but interrelated systems. The systems have different capacities, duration of storing information and they store different types of information (Cohen and Eichenbaum 2001). Short-term memory has a limited storage capacity of up to seven items or chunks. Another distinguishing characteristic of short-term memory is that information is stored for brief duration of about 30 seconds (Anderson1983). Therefore, the type of information stored in short-term memory includes visual images, words and sentences and other information that is of little significance to a person. Christian et al (2000) attributed the quick forgetting of information stored in short-term memory to displacement of the old information by incoming material. The effectiveness of short-term memory decreases with increase in age and it could be improved by chunking of information and consistent rehearsal. Experimental evidence have proved that long-term memory has unlimited capacity and the duration of storing information ranges from days to the lifetime of an individual (Christian et al, 2000). In this respect, long-term memory stores meaningful and significant events and information. Baddeley (1997) noted that information stored in long-term memory is mainly forgotten due to interference and poor organization of the stored material. The ability to store and recall information in the long-term memory depends on the age, and it is poorest in children below three years and old people. Neuropsychologists have further classified long-term memory into distinct but interrelated systems. These systems include episodic, procedural and semantic memory (Tulving, 2006). Although the classification has elicited criticism from some theorists, it has enabled b better understanding of the structure and the functioning of human memory. According to Christian et al (2000), episodic memory is the highest memory system and it enables people to recall personal events from the past. Therefore, episodic remembrance is a mental occurrence because it involves a conscious and unique experience that every human being can identify as such. Episodic memory differs from imagination, perception, dreams and hallucination because it is a distinct phenomenon that Anderson (1983) defined as “direct feeling, where the object in question is immersed with warmth and intimacy that no object or conception can ever achieve”. Tulving (2006) argues that episodic memory for events is concerned with specific or particular personal experiences that took place in the past. In the definition of episodic memory, the term experience stresses on the critical importance of the inner and phenomenal aspect of episodic recalling. Therefore, the conscious awareness makes this form of memory explicit, differentiating it from other forms of implicit memory that lack similar kind of consciousness. The relationship between recognition and recall has been the subject of researchers, studying episodic memory. Therefore, episodic memory is construed to contain subsystems that mediate recall and recognition. The existence of these subsystems has been proved experimentally whereby brain damage was found to damage them differently (Baddeley, 1997). The different effect that brain damage has on recall and recognition is an indicator that these subsystems are separate, served by different mechanisms in the brain. Semantic memory follows episodic memory in the classification order. According to Anderson, (1983), semantic memory enables an individual to construct mental models of the world in both concrete and abstract models. Therefore, it enables the cognitive depiction of objects, events, situations and facts and the usage of information shown in the absence of the original stimulation. The main distinguishing characteristic of semantic from episodic memory is that the information about a particular event, situation or object, could be shared with different persons and it constitutes the highest proportion of information shared by people. In addition, semantic memory is retained for longer periods than episodic. Semantic memory is used to store numerical and verbal codes and their importance and hence it is a memory of facts (Tulving, 2006). Procedural memory is another system of long-term memory that human beings use to preserve learned experiences between the stimulus and the response. This includes the intricate stimulus –response behavioral patterns that do not require a reference to external factors to trigger a response. Experimental evidence indicates that human beings and organisms require take long periods to acquire this type of memory (Christian, et al 2000). However, unlike other systems, the information contained in this type of long-term memory does not have truth-value and the expression of information occurs through behavioral patterns although in some cases it happens automatically. In human beings, procedural memory is used to show how to conduct a sequence of actions (Tulving, 2006). References Anderson, J.(1983). The architecture of cognition. Cambridge, MA,: Harvard University Press. Baddeley, A. (1997). Human memory: theory and practice. London: Psychology Press. Christian, F., et al (2000). Brain imaging of human memory systems: between-systems similarities and within -system differences. Cognitive Brain Research, 13, : 280-296. Cohen, J. and Eichenbaum, H. (2001). From conditioning to conscious recollection. New York: Oxford University Press. Tulving, E. (2006). Multiple memory systems and consciousness. Human Neurobiology, 6: 70- 81. Read More

 

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