ForgettingI. Early researchesHermann Ebbinghaus: a

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.
                                Forgetting
    Good morning. If I ask you " Have you ever forgotten anything?" I guess the answer will mostly be "Yes." We all forget things. Today, we shall discuss how we measure forgetting and retention and why we forget things.
    Memory researchers certainly haven’t forgotten Hermann Ebbinghaus, the first person to do scientific studies of forgetting, using himself as a subject. He spent a lot of time memorizing endless lists of nonsense syllables and then testing himself to see whether he remembered them. He found that he forgot most of what he learned during the first few hours after learning it. On that basis, he drew a forgetting curve which shows how quickly learned information is forgotten over time.
    Later researchers have found that forgetting doesn’t always occur that quickly. Meaningful information fades more slowly than nonsense syllables. The rate at which people forget or retain information also depends on what method is used to measure forgetting and retention. Retention is the proportion of learned information that is retained or remembered — the flip side of forgetting.
    Researchers measure forgetting and retention in three different ways: recall, recognition, and relearning.
    Recall is remembering without any external cues. For example, essay questions test recall of knowledge because nothing on a blank sheet of paper will jog the memory.
    Recognition is identifying learned information using external cues. For example, true-or-false questions and multiple-choice questions test recognition because the previously learned information is there on the page, along with other options. In general, recognition is easier than recall.
    When using the relearning method to measure retention, a researcher might ask a subject to memorize a long grocery list. She might measure how long he has to practice before he remembers every item. Suppose it takes him ten minutes. On another day, she gives him the same list again and measures how much time he takes to relearn the list. Suppose he now learns it in five minutes. He has saved five minutes of learning time, or 50 percent of the original time it took him to learn it. His savings score of 50 percent indicates that he retained 50 percent of the information he learned the first time.
    Then why do we forget? Researches suggest that there are all together six main reasons for forgetting.
    First, ineffective encoding. The way information is encoded affects the ability to remember it. Processing information at a deeper level makes it harder to forget. If a student thinks about the meaning of the concepts in her textbook rather than just reading them, she’ll remember them better when the final exam comes around. If the information is not encoded properly — such as if the student simply skims over the textbook while paying more attention to the TV — it is more likely to be forgotten.
    Secondly, decay. According to decay theory, memory fades with time. Decay explains the loss of memories from sensory and short-term memory. However, loss of long-term memories does not seem to depend on how much time has gone by since the information was learned. People might easily remember their first day in junior high school but completely forget what they learned in class last Tuesday.
    Thirdly, interference. Interference theory has a better account of why people lose long-term memories. According to this theory, people forget information because of interference from other learned information. There are two types of interference: retroactive and proactive.
    Retroactive interference happens when newly learned information makes people forget old information.
    Proactive interference happens when old information makes people forget newly learned information.
    Fourthly, retrieval failure. Forgetting may also result from failure to retrieve information in memory, such as if the wrong sort of retrieval cue is used. For example, Dan may not be able to remember the name of his fifth-grade teacher. However, the teacher’s name might suddenly pop into Dan’s head if he visits his old grade school and sees his fifth-grade classroom. The classroom would then be acting as a context cue for retrieving the memory of his teacher’s name.
    Fifthly, motivated forgetting. Psychologist Sigmund Freud proposed that people forget because they push unpleasant or intolerable thoughts and feelings deep into their unconscious. He called this phenomenon repression. The idea that people forget things they don’t want to remember is also called motivated forgetting or psychogenic amnesia.
    Sixthly, physical injury or trauma. Anterograde amnesia is the inability to remember events that occur after an injury or traumatic event. Retrograde amnesia is the inability to remember events that occurred before an injury or traumatic event.
    In spite of all these reasons for forgetting, people can still remember a vast amount of information. In addition, memory can be enhanced in a variety of ways, including rehearsal, overlearning, distributed practice, minimizing interference, deep processing, organizing information, mnemonic devices, and visual imagery. We are going to deal with those methods in our next lecture. Thank you for your time.