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SHORT TERM MEMORY. Short Term Memory : A memory system with limited storage capacity and duration in which information is lost rapidly unless it is rehearsed. Short Term Memory is sometimes referred to as ‘working memory’ as it provides a place for mental work. Duration!.
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SHORT TERM MEMORY
Short Term Memory : A memory system with limited storage capacity and duration in which information is lost rapidly unless it is rehearsed. Short Term Memory is sometimes referred to as ‘working memory’ as it provides a place for mental work.
Duration! Duration is the amount of time a memory lasts in out short term memory.The duration of Short Term Memory lasts up to about 18-20 seconds and occasionally goes up to 30 seconds.
Experiment on Duration. • An experiment conducted by Margret and Lloyd Peterson in 1959. Participants were given were given trigrams these are (meaningless groups of three letters) to memorise. For example items such as qlg, jmb and mwt. Immediately after the trigrams were presented the participants were given a distracter or an interference task, where they required to starting counting backwards by threes from a three digit number for example: 634, 631 and 628. This was done to prevent rehearsal of trigrams. Following a time interval that varied from 3 to 18 seconds a light was used to signal that participants were required to recall the trigrams.
Results: The graph shows the longer the interval, the less likely a participant was to accurately recall a trigram. By 18 seconds after the presentation of the trigrams, participants had forgotten almost all of the trigrams. When participants did not have to count backwards, their performance was much better possibly because they were rehearsing the items to themselves. In similar conditions if you repeat a telephone number over to yourself it can be retained in the Short Term Memory indefinitely. But if you look up a telephone number and then get distracted, you are likely to forget the number almost immediately.
Capacity of Short term memory. • Capacity - the amount of information we can hold at any one time • STM is very limited in storage capacity compared to sensory memory and long term memory. Rarely are we able to hold more than between 5 and 9 bits of information in STM at any given time regardless of the nature of that information. The limit of STM is described as having a range of 7+2 items of information.
Capacity • Example - read the following numbers, one at a time, and then (without looking at them) write them immediately on a piece of paper: 7,2,9,4,1,8,3. • Next read the following numbers, at one time, immediately from memory: 4,9,1,7,3,8,6,3,9,5,7 • If you have 'average' STM storage capacity, you were probably able to recall the seven numbers in the first set but not all of the 11 numbers in the second set.
Estimates of the capacity of STM are obtained by asking research participants to memories simple lists of data of different lengths; for example randomly ordered numbers, letters, nonsense syllables or unrelated words. the length of the list that the participants can recall half the time is considered to represent the capacity of short term memory. Space in STM is filled when we think and when information is temporarily brought from LTM into working memory to be used or updated. This is why you cannot remember the telephone number you have just looked up if you begin thinking about what you might say before you dial the number. Information stored in STM is lost primarily through decay (not being used) and displacement (being pushed out) by new information. Decay of information in STM occurs when you forget what you want to say in a conversation while you wait for another person involved in the conversation to finish what they are saying. Your thoughts quickly fade from STM because listening to what the speaker is saying prevents you from rehearsing and therefore maintaining in STM the point you wanted to make. It is difficult for us to think about problems involving more than 7+2 issues (items). We forget some aspects of the problem because they exceed the capacity of STM. in such situations, writing down all the points to be considered prevents the information from being lost while the central executive in your working memory is focused on another aspect of the problem.
Chunking • Chunking is the grouping of separate bits of information into chunks of information. • E.g.. A sequence of letters‘D N V R C E W V D C S V’These will be hard to remember as they are 12 separate pieces of information. • However we can remember them as chunks if we see them like this ‘NSW VCR VCE DVD’ we now see them as four separate chunks. • Chunking requires fewer eye movement and the brain processes the chunks as units rather than individuals, making it easier to remember.
Effects of rehearsal • INFORMATION CAN BE KEPT IN STM FOR LONGER THAN THE USUAL MAXIMUM OF ABOUT 20 SECONDS,IF IT IS REHEARSED IN SOME WAY. IN THE STUDY OF MEMORY REHEARSAL IS THE PROCESS OF ACTIVELY MANIPULATING INFORMATION SO THAT IT CAN BE RETAINED IN MEMORY.THERE ARE TWO MAIN TYPES OF REHEARSAL: MAINTENANCE REHEARSAL AND ELABORATIVE REHEARSAL.
Maintenance rehearsal=Involves repeating the information being remember over and over again to retain in STM. maintenance rehearsal can either be verbal (words),sub-vocally(silently repeating the information if your head), or non-verbal(involving visual or spatial information).Elaborative rehearsal: when represented with new information that will be tested at a later date, many students think That repeating the information over and over again will assist them to retain the info in LTM. Elaborative rehearsal involves organizing and dealing with information in terms of its meaning.
Consolidation Theory. • Consolidation theory: proposes that physical changes to the neurons in the brain occurs due to someone learning something new and immediately following learning. These changes occur for a period of time after learning takes place, as the new information consolidates (or sets) in memory.Consolidation: To bring together into a single whole or system. (to finalise)
So in other words, when we all learn something new, the neurons in our brain become active as we take in the new info (whether it be before or after), and not long after we store it into our memory. The changes in our brain is the process of storing that new learned information as memory, where it can be retrieved later on or stored as it is. This is CONSOLIDATION THEORY.
It is the learning of short-term memory into Long-term memory.It is also proposed that if the memory is disrupted (eg-your trying to consolidate a school fight) during our consolidation phase, information may not process through to long-term memory and will therefore be lost. (eg- a friend from school comes over to you and talks about something far more interesting, therefore prohibiting the brain from finalising the fight that had happened and focusing on the story being told by the friend.)However, if disruption does not occur, we can assume that the information being finalised has been stored into long-term memory. Consolidation of information is a gradual process and takes 30 minutes to do so thus leaving the brain vulnerable to disruption during those 30 minutes. Additionally, the consolidation of memory can proceed for many years once stored safely!
For exampleThe consolidation of STM to LTM can be compared with writing your name in wet concrete. Once the concrete has "set" (the info consolidated into LTM), your name (the information) is permanent. But while it is setting (the process of consolidation), it can be interefered with (altered) or erased (completely lost).