Encoding, Storage and Retrieval in Human Memory

Human beings have three types of memory: sensory, short term and long term. Sensory memories are formed through our senses of sight, taste, touch, sound and smell. There are two main types of sensory memories – iconic memory and echoic memories. Iconic memories are formed through visual information from our environment and echoic memoires are formed through auditory information from our environment (Goddard, 2012). Short term memories are formed when sensory information is consciously paid attention to, rehearsed, or reinforced in order to attempt to maintain it. Further rehearsal and use of short-term memories leads to the formation of long-term memories. Long term memories are categorised into explicit and implicit memories. Explicit memories refer to knowledge and personal experiences that can be consciously recalled whereas implicit memories are unconsciously recalled which influence our behaviours (Brewer, Gabrieli, Preston, Vaidya & Rosen, 2007). There are number of theories about the way memories are formed, held and recalled. It is commonly accepted that memories are encoded, stored and retrieved, and that understanding this process is helpful for many human experiences such as learning. The encoding process involves interpreting the environment, which is done visually, acoustically and semantically. After the encoding process information is stored so that it can be retrieved when needed (Brem, Ran & Pascual-leone, 2013). This essay will explore the three different types of memory mentioned earlier and how the encoding, storage and retrieval model explains the process of forming, maintaining and recalling memories.

Through encoding, memories begin to form, this occurs by using our senses to interpret the environment around us. This information is then organised with similar memories and used to form new links with existing memories. Encoding occurs automatically so that information in the environment that is not important to remember is discarded but through conscious effort and by paying attention to what we would like to remember the information can be retained. There are three types of encoding, semantic, visual and acoustic. Semantic encoding refers to the encoding of words and their meanings. One of the experiments demonstrating that individuals code information semantically was conducted by William Bousfield in 1953. When participants were asked to memories randomly presented words that could be organised into four categories based on their meaning, they recalled them in categories which shows that they paid attention to what the words meant and demonstrated that one of the ways that memory is encoded is semantically (Bousfield, 1953). The encoding of visual stimuli is known as visual encoding and the encoding of sound, words and other auditory input is known as acoustic encoding (Sperling, 1963). Visual encoding occurs through sight. Pavio (1991) found that words that evoke a mental image (such as trees and window) are more likely to be remembered compared to abstract words (such as lies and justice) as they are encoded both visually and semantically (Paivio, 1991). Acoustic encoding occurs through encoding auditory information. By turning auditory information into songs, rhymes or stories stronger memories can be formed. This can be seen in the different way’s children are taught various things such as the alphabets (Esrov, Hall & LaFaver, 1974). Through conducting various experiments, Craik and Tulving (1975) found out which form of encoding was the most effective. They found that words that were semantically encoded were more likely to be remembered than those encoded visually or acoustically (Craik & Tulving, 1975). This is because semantic encoding involves a greater level of processing (Craik & Tulving, 1975).

After encoding information, it is then stored in order to be able to retrieve it later. The storage of information can either be permanent or semi-permanent. Information that is perceived and processed from the environment can be stored short-term or long-term. Richard Atkinson and Richard Shiffrin (1968) proposed that to form long term memories, information passes through three distinct stages – sensory memory, short-term memory and long-term memory.

Sensory memory is the first stage of memory. Sensory memory is subdivided into iconic memories which last about half a second, and echoic memories which lasts about 3 to 4 seconds (Sperling, 1963). An experiment conducted by John Ridley Stroop on sensory memory suggest that new information is more likely to be stored when connected to long term memories (Stroop, 1935). Information viewed as valuable is then moved into our short-term memory system (Cowan, 2008)

Short-term memory retains information from sensory memory through rehearsal and attention, it is a temporary storage stage; it is also known as working memory. Short-term memories storage capacity is about 20 seconds (Brewer, Gabrieli, Preston, Vaidya & Rosen, 2007). The amount of information that can be stored in short-term memory and the length of time it can be stored for is limited. Peterson and Peterson (1959) performed a task were participants were presented a list of three-letter strings and asked to remember them. They were then asked to perform another task in order to distract them. By doing this, Peterson and Peterson (1959) found that material was quickly forgotten due to their distraction task (Peterson & Peterson, 1959). Research conducted by George Miller (1956), found that short-term memory has the capacity to store 7 items, plus or minus 2. One of the ways to maintain information is through rehearsal. When memories are used and accessed over and over it is more likely to be transferred it to long-term memory (Brewer, Gabrieli, Preston, Vaidya & Rosen, 2007). Another way to retain information in short term memory is through a technique called chunking which involves grouping information together (Simon & Chase, 1973). The experiment conducted by Herbert Simon and William Chase (1973) illustrated how chunking is used in short term memory. Herbert Simon and William Chase (1973) showed chess novices and chess masters a chessboard with chess pieces arranged in various positions for a few seconds in order to test if they could recall the position of the pieces. Chess masters were more able to recall the position of the pieces as they had grouped them into larger layouts which illustrates that through chunking information is more likely to be stored. However, when both groups were shown positions that would not occur in a real game and were therefore not easy to chunk, both groups did poorly (Chase & Simon, 1973).

Through rehearsal, the conscious repetition of information, short-term memory is moved into long-term memory through the process called memory consolidation.

The capacity of long-term memory is unlimited (Wang, Liu, & Wang, 2003). However, not all long-term memories are strong memories. Some can only be recalled if prompted. Long-term memory consists of explicit and implicit memories. The storage of facts and events we personally experience are explicit memories. Explicit memories have two parts: semantic memory which refers to information about words, concepts, and language-based knowledge, and episodic memory which is information about events that we have personally experienced. Episodic memories are the ones we constantly access. About 40 years ago, episodic memory was first proposed (Tulving, 1972). Tulving and others since then have done further research and developed a reformulated theory. It is currently believed that episodic memory is memory that has be kept in storage about events occurring in a particular place at a particular time, as well as the when, what and where of an event (Tulving, 2002). Episodic memory involves the recollection of visual stimuli and the feeling of familiarity (Hassabis & Maguire, 2007).

Memories that are unconscious are implicit memories. These are memories that are formed from behaviours. Implicit memories include procedural memories, which is information about how to do things and information learned through conditioning. Procedural memories are for skilled actions, such as how to drive a car or brush your teeth (Ullman, 2016).

The final stage of the memory process is retrieval. In order to recover memories out of storage and back it our conscious mind we have to retrieve it. The capacity to recover information from our long-term memory is essential to our everyday functioning (Brem, Ran & Pascual-leone, 2013). Without being able to retrieve information from our memory we would not be able to carry through with our daily tasks such as performing our job or driving home from work.

Information can be retrieved from our long-term memory in three ways: recall, recognition and relearning. Recall is the most frequent type used to retrieve memory; the information is accessible without cues.  For example, recall would be used in an exam. Recognition is the second type of retrieval method. Recognition occurs when previously learnt or encountered information is re-identified. Recognition is a type of retrieval which requires a process of comparison. For example, when sitting in exam we use recognition to write answers. Recognition is considered to be the most effective form of retrieval when compared to recall as recall is a two-step process (Watkins & Gardiner, 1979). Relearning is the third form of retrieval, it involves learning previously learnt information, an example of this is re-learning a language that you had once learnt before, since it was learnt in the past it Is easier to pick up on.

In conclusion, the encoding, storage and retrieval model is sufficient to capture the fundamental cognitive processes involved in human memory. The three processes are inclusive of all the complexities in human memory and the model has been a foundation for many other models such as the Atkinson-Shiffrin model. Each cognitive process plays a vital part in the formation of human memory.

References

• Atkinson, R., & Shiffrin, R. (1968). Human Memory: A Proposed System and its Control Processes. Psychology Of Learning And Motivation, 89-195. doi: 10.1016/s0079-7421(08)60422-3
• Bousfield, W. (1953). The Occurrence of Clustering in the Recall of Randomly Arranged Associates. The Journal Of General Psychology, 49(2), 229-240. doi: 10.1080/00221309.1953.9710088
• Brem, A., Ran, K., & Pascual-leone, A. (2013). Learning and memory. Handbook Of Clinical Neurology, 693-737. doi: 10.1016/b978-0-444-53497-2.00055-3
• Brewer, J., Gabrieli, J., Preston, A., Vaidya, C., & Rosen, A. (2007). Memory. Textbook Of Clinical Neurology, 63-78. doi: 10.1016/b978-141603618-0.10005-0
• Chase, W., & Simon, H. (1973). Perception in chess. Cognitive Psychology, 4(1), 55-81. doi: 10.1016/0010-0285(73)90004-2
• Cowan, N. (2008). Sensory Memory. Learning And Memory: A Comprehensive Reference, 23-32. doi: 10.1016/b978-012370509-9.00172-8
• Craik, F., & Tulving, E. (1975). Depth of processing and the retention of words in episodic memory. Journal Of Experimental Psychology: General, 104(3), 268-294. doi: 10.1037//0096-3445.104.3.268
• Esrov, L., Hall, J., & LaFaver, D. (1974). Preschoolers’ conceptual and acoustic encoding as evidenced by release from PI. Bulletin Of The Psychonomic Society, 4(2), 89-90. doi: 10.3758/bf03334204
• Goddard, N. (2012). Psychology. Core Psychiatry, 63-82. doi: 10.1016/b978-0-7020-3397-1.00005-7
• Hassabis, D., & Maguire, E. A. (2007). Deconstructing episodic memory with construction. Trends in cognitive sciences, 11(7), 299-306.
• Miller, G. (1956). The magical number seven, plus or minus two: some limits on our capacity for processing information. Psychological Review, 63(2), 81-97. doi: 10.1037/h0043158
• Paivio, A. (1991). Dual coding theory: Retrospect and current status. Canadian Journal Of Psychology/Revue Canadienne De Psychologie, 45(3), 255-287. doi: 10.1037/h0084295
• Peterson, L., & Peterson, M. (1959). Short-term retention of individual verbal items. Journal Of Experimental Psychology, 58(3), 193-198. doi: 10.1037/h0049234
• Sperling, G. (1963). A Model for Visual Memory Tasks. Human Factors: The Journal Of The Human Factors And Ergonomics Society, 5(1), 19-31. doi: 10.1177/001872086300500103
• Stroop, J. (1935). Studies of interference in serial verbal reactions. Journal Of Experimental   Psychology, 18(6), 643-662. doi: 10.1037/h0054651
• Tulving, E. (1972). Episodic and semantic memory. Organization of memory, 1, 381-403.
• Tulving, E. (2002). Episodic memory: from mind to brain. Annual review of psychology, 53(1), 1-25.
• Ullman, M. (2016). The Declarative/Procedural Model. Neurobiology Of Language, 953-968. doi: 10.1016/b978-0-12-407794-2.00076-6
• Wang, Y., Liu, D., & Wang, Y. (2003). Brain And Mind, 4(2), 189-198. doi: 10.1023/a:1025405628479
• Watkins, M., & Gardiner, J. (1979). An appreciation of generate-recognize theory of recall. Journal Of Verbal Learning And Verbal Behavior, 18(6), 687-704. doi: 10.1016/s0022-5371(79)90397-9