Short-term Memory
短時(shí)記憶
There are two kinds of memory: short-term and long-term. Information in long-term memory can be recalled at a later time when it is needed. The information may be kept for days or weeks. Sometimes information in the long-term memory is hard to remember. Students taking exams often have this experience. In contrast, information in short-term memory is kept for only a few seconds, usually by repeating the information over and over. For example, you look up a number in the telephone book, and before you dial, you repeat the number over and over. If someone interrupts you, you will probably forget the number. In laboratory studies, subjects are unable to remember three letters after eighteen seconds if they are not allowed to repeat the letters to themselves.
Psychologists study memory and learning with both animal and human subjects. The two experiments here show how short-term memory has been studied.
Dr. Hunter studied short-term memory in rats. He used a special apparatus which had a cage for the rat and three doors. There was a light in each door. First the rat was placed in the closed cage. Next, one of the lights was turned on and then off. There was food for the rat only at this door. After the light was turned off, the rat had to wait a short time before it was released form its cage. Then, if it went to the correct door, it was rewarded with the food that was there. Hunter did this experiment many times. He always turned on the lights in a random order. The rat had to wait different intervals before it was released from the cage. Hunter found that if the rat had to wait more than ten seconds, it could not remember the correct door. Hunter's results show that rats have a short-term memory of about ten seconds.
Later, Dr. Henning studied how students who are learning English as a second language remember vocabulary. The subject in his experiment were 75 students at the University of California in Los Angeles. They represented all levels of ability in English: beginning, intermediate, advanced, and native-speaking students.
To begin, the subjects listened to a recording of a native speaker reading a paragraph in English. Following the recording, the subjects took a 15-question test to see which words they remembered. Each question has four choices. The subjects had to circle the word they had heard in the recording. Some of the questions had four choices that sound alike. For example, weather, whether, wither, and wetter are four words that sound alike. Some of the questions had four choices that have the same meaning. Method, way, manner, and system would be four words with the same meaning. Some of them had four unrelated choices. For instance, weather, method, love, and result could be used as four unrelated words. Finally the subjects took a language proficiency test.
Henning found that students with a lower proficiency in English made more of their mistakes on words that sound alike; students with a higher proficiency made more of their mistakes on words that have the same meaning. Henning's results suggest that beginning students hold the sound of words in their short-term memory, while advanced students hold the meaning of words in their short-term memory.
有兩種記憶:短時(shí)記憶和長(zhǎng)時(shí)記憶。處于長(zhǎng)期記憶中的信息,在后來(lái)需要的時(shí)候能夠回想起來(lái)。這一信息可以保持?jǐn)?shù)天或數(shù)周。有時(shí)處于長(zhǎng)時(shí)記憶中的信息很難記起。參加考試的學(xué)生經(jīng)常會(huì)有這種經(jīng)歷。反之,短時(shí)記憶中的信息只能保持三兩秒鐘,通常還得再三復(fù)習(xí)這一信息。例如,你在一本電話號(hào)碼簿中查到一個(gè)號(hào)碼,在你還沒撥號(hào)之前,你得再三復(fù)習(xí)這一號(hào)碼。如果這時(shí)有人打擾了你,你也許會(huì)把這個(gè)電話號(hào)碼忘了。通過(guò)實(shí)驗(yàn)研究表明,如果不準(zhǔn)被測(cè)試的人復(fù)習(xí),那么十八秒以后,被測(cè)試的人連三個(gè)字母都記不住。
心理學(xué)家們以動(dòng)物和人這二者做測(cè)試對(duì)象分別研究了記憶和學(xué)習(xí)的情況。這里這兩類試驗(yàn)都表明了研究短時(shí)記憶的情況。
亨特博士研究了大老鼠的短時(shí)記憶。他用了一種特殊裝置,這種裝置上有個(gè)鼠籠和三扇門。每扇門上都有一盞燈。首先,把大老鼠放到一個(gè)關(guān)著的鼠籠里。接著,把其中一盞燈打開然后再關(guān)上。只有在這扇門那里才有給老鼠吃的東西。在把燈關(guān)掉以后,必須讓這個(gè)老鼠等候一段短時(shí)期,這才把它從鼠籠中放出去。接下來(lái),如果這個(gè)老鼠走對(duì)了門,那么,門那里擺著的食物就是對(duì)他的獎(jiǎng)賞。亨特博士多次做過(guò)這種實(shí)驗(yàn)。他總是沒有按固定順序隨便打開任何一盞燈。讓老鼠等候的時(shí)間間隔也完全不同,然后才把大老鼠從鼠籠中放出去。亨特博士發(fā)現(xiàn),如果老鼠必須等候10秒鐘以上才放出,那它就記不住哪扇門是正確的。亨特博士實(shí)驗(yàn)的結(jié)果表明大老鼠能有大約10秒鐘的短期記憶。
后來(lái),享尼希博士研究了那些把英語(yǔ)作為第二種語(yǔ)言來(lái)學(xué)習(xí)的人,是怎樣記生詞的。他實(shí)驗(yàn)的對(duì)象是洛杉磯加州大學(xué)的75名學(xué)生。他們都是各種程度的英語(yǔ)學(xué)生中的代表人物:初級(jí)的、中級(jí)的、高級(jí)和以英語(yǔ)為母語(yǔ)的學(xué)生。
開頭,先讓受試者們聽一段以英語(yǔ)為母語(yǔ)的人所朗讀的一小段英文文章的錄音。聽了錄音以后接著讓受試者參加一次共15個(gè)問(wèn)題的考試,看看他們都記住了哪些生詞。每個(gè)問(wèn)題有四個(gè)選擇項(xiàng)。受試者必須圈出他們?cè)阡浺糁兴牭降膯卧~。每個(gè)問(wèn)題有四個(gè)選擇項(xiàng)聽起來(lái)很像是一樣的。例如:weather天氣,whether是否,wither枯萎,wetter潤(rùn)濕劑。有些問(wèn)題的選擇項(xiàng)的意義像是一樣的:method,way,manner和system.有些問(wèn)題的四個(gè)選擇項(xiàng)之間沒有任何關(guān)連:weather,method,love和result.最后,受試者們都參加一次語(yǔ)言熟練程度的測(cè)試。
享尼希博士發(fā)現(xiàn),凡是英語(yǔ)熟練程度低的學(xué)生多在聲音相似的單詞中會(huì)弄錯(cuò);凡是英語(yǔ)熟練程度高的學(xué)生多在意義相似的詞匯上會(huì)出錯(cuò)。享尼希的實(shí)驗(yàn)結(jié)果表明:初學(xué)者能把單詞的聲音保持短期記憶。享尼希的實(shí)驗(yàn)結(jié)果表明:初學(xué)者能把單詞的聲音保持短期記憶,而程度高的學(xué)生能把詞匯的意義保持短期記憶。