MemoryI. Introduction to memory— the capacity

In this section you will hear a mini-lecture. You will hear the mini-lecture ONCE ONLY. While listening to the mini-lecture, please complete the gap-filling task on ANSWER SHEET ONE and write NO MORE THAN THREE WORDS for each gap. Make sure the word(s)you fill in is(are)both grammatically and semantically acceptable. You may use the blank sheet for note-taking.
    You have THIRTY seconds to preview the gap-filling task.
     (a thirty-second interval)
    Now listen to the mini-lecture. When it is over, you will be given THREE minutes to check your work.
                                Memory
    Good afternoon. Memory is something that we live with every minute, but we are not that familiar with it as we suppose. It is just one of many phenomena that demonstrate the brain’s complexity. On a basic level, memory is the capacity for storing and retrieving information, but memories are not simply recorded and neatly stored. Our memories are selected, constructed, and edited not just by us but by the world around us. We have an astounding, boundless capacity for memory, but our memories are also faulty, full of holes and distortions, and hampered by unreliable data retrieval systems.
    In today’s lecture, I’m going to introduce to you the processes of memory.
    Memory researchers explore the many mysteries of remembering. They examine why the name of a favorite elementary school teacher might leap easily to mind, while the time and place of a committee meeting prove maddeningly elusive. They try to explain why we have trouble remembering a person’s name — only to recall it later, after the person is gone. We still have much to learn about how memories are made and what determines whether they last or fade away.
    Studies show whether something is remembered or forgotten is, specifically, determined by the three processes involved in memory: encoding, storage, and retrieval.
    Encoding refers to processing information into memory. People automatically encode some types of information without being aware of it. For example, most people probably can recall where they ate lunch yesterday, even though they didn’t try to remember this information. However, other types of information become encoded only if people pay attention to it. College students will probably not remember all the material in their textbooks unless they pay close attention while they’re reading.
    There are several different ways of encoding verbal information:
    Structural encoding, which focuses on what words look like. For instance, one might note whether words are long or short, in uppercase or lowercase, or handwritten or typed.
    Phonemic encoding, which focuses on how words sound.
    Semantic encoding, which focuses on the meaning of words. It requires a deeper level of processing than structural or phonemic encoding and usually results in better memory.
    After information enters the brain, it has to be stored or maintained. To describe the process of storage, many psychologists use the three-stage model proposed by Richard Atkinson and Richard Shiffrin. According to this model, information is stored sequentially in three memory systems: sensory memory, short-term memory, and long-term memory.
    Sensory memory stores incoming sensory information in detail but only for an instant. The capacity of sensory memory is very large, but the information in it is unprocessed. If a flashlight moves quickly in a circle inside a dark room, people will see a circle of light rather than the individual points through which the flashlight moved. This happens because sensory memory holds the successive images of the moving flashlight long enough for the brain to see a circle.
    Some of the information in sensory memory transfers to short-term memory, which can hold information for approximately twenty seconds. Rehearsing can help keep information in short-term memory longer. When people repeat a new phone number over and over to themselves, they are rehearsing it and keeping it in short-term memory.
    Short-term memory has a limited capacity: It can store about seven pieces of information, plus or minus two pieces. These pieces of information can be small, such as individual numbers or letters, or larger, such as familiar strings of numbers, words, or sentences. A method called chunking can help to increase the capacity of short-term memory. Chunking combines small bits of information into bigger, familiar pieces.
    Psychologists today consider short-term memory to be a working memory. Rather than being just a temporary information storage system, working memory is an active system. Information can be kept in working memory while people process or examine it. Working memory allows people to temporarily store and manipulate visual images, store information while trying to make decisions, and remember a phone number long enough to write it down.
    Then, information can be transferred from short-term memory to long-term memory and from long-term memory back to short-term memory. Long-term memory has an almost infinite capacity, and information in long-term memory usually stays there for the duration of a person’s life. However, this doesn’t mean that people will always be able to remember what’s in their long-term memory — they may not be able to retrieve information that’s there.
    Finally, we come to retrieval. It is the process of getting information out of memory, in which retrieval cues play an important part. They are stimuli that help the process of retrieval. They include associations, context, and mood. Because the brain stores information as networks of associated concepts, recalling a particular word becomes easier if another related word is recalled first. With regard to context, people can often remember an event by placing themselves in the same context they were in when the event happened. Moreover, if people are in the same mood they were in during an event, they may have an easier time recalling the event. If we can make conscious use of these retrieval cues, we can largely enhance our memory.
    Today, we’ve looked at the processes of memory, i.e. encoding, storage and retrieval, and the three stages of memory. We are going to look deeper into the issue of memory next time. Thank you.