更改

Working memory is widely acknowledged as having limited capacity. An early quantification of the capacity limit associated with short-term memory was the "magical number seven" suggested by Miller in 1956. He claimed that the information-processing capacity of young adults is around seven elements, which he called "chunks", regardless of whether the elements are digits, letters, words, or other units. Later research revealed this number depends on the category of chunks used (e.g., span may be around seven for digits, six for letters, and five for words), and even on features of the chunks within a category. For instance, span is lower for long than short words. In general, memory span for verbal contents (digits, letters, words, etc.) depends on the phonological complexity of the content (i.e., the number of phonemes, the number of syllables), and on the lexical status of the contents (whether the contents are words known to the person or not). Several other factors affect a person's measured span, and therefore it is difficult to pin down the capacity of short-term or working memory to a number of chunks. Nonetheless, Cowan proposed that working memory has a capacity of about four chunks in young adults (and fewer in children and old adults).

Working memory is widely acknowledged as having limited capacity. An early quantification of the capacity limit associated with short-term memory was the "magical number seven" suggested by Miller in 1956. He claimed that the information-processing capacity of young adults is around seven elements, which he called "chunks", regardless of whether the elements are digits, letters, words, or other units. Later research revealed this number depends on the category of chunks used (e.g., span may be around seven for digits, six for letters, and five for words), and even on features of the chunks within a category. For instance, span is lower for long than short words. In general, memory span for verbal contents (digits, letters, words, etc.) depends on the phonological complexity of the content (i.e., the number of phonemes, the number of syllables), and on the lexical status of the contents (whether the contents are words known to the person or not). Several other factors affect a person's measured span, and therefore it is difficult to pin down the capacity of short-term or working memory to a number of chunks. Nonetheless, Cowan proposed that working memory has a capacity of about four chunks in young adults (and fewer in children and old adults).

Whereas most adults can repeat about seven digits in correct order, some individuals have shown impressive enlargements of their digit span—up to 80 digits. This feat is possible by extensive training on an encoding strategy by which the digits in a list are grouped (usually in groups of three to five) and these groups are encoded as a single unit (a chunk). For this to succeed, participants must be able to recognize the groups as some known string of digits. One person studied by Ericsson and his colleagues, for example, used an extensive knowledge of racing times from the history of sports in the process of coding chunks: several such chunks could then be combined into a higher-order chunk, forming a hierarchy of chunks. In this way, only some chunks at the highest level of the hierarchy must be retained in working memory, and for retrieval the chunks are unpacked. That is, the chunks in working memory act as retrieval cues that point to the digits they contain. Practicing memory skills such as these does not expand working memory capacity proper: it is the capacity to transfer (and retrieve) information from long-term memory that is improved, according to Ericsson and Kintsch (1995; see also Gobet & Simon, 2000).

Whereas most adults can repeat about seven digits in correct order, some individuals have shown impressive enlargements of their digit span—up to 80 digits. This feat is possible by extensive training on an encoding strategy by which the digits in a list are grouped (usually in groups of three to five) and these groups are encoded as a single unit (a chunk). For this to succeed, participants must be able to recognize the groups as some known string of digits. One person studied by Ericsson and his colleagues, for example, used an extensive knowledge of racing times from the history of sports in the process of coding chunks: several such chunks could then be combined into a higher-order chunk, forming a hierarchy of chunks. In this way, only some chunks at the highest level of the hierarchy must be retained in working memory, and for retrieval the chunks are unpacked. That is, the chunks in working memory act as retrieval cues that point to the digits they contain. Practicing memory skills such as these does not expand working memory capacity proper: it is the capacity to transfer (and retrieve) information from long-term memory that is improved, according to Ericsson and Kintsch (1995; see also Gobet & Simon, 2000).

虽然大多数成年人能够正确地重复大约7个数字，但有些个人的数字跨度有令人印象深刻的扩大ーー达到80个数字。通过对编码策略的广泛培训，可以实现这一壮举。编码策略是将列表中的数字分组(通常为三到五个组) ，并将这些组编码为单个单元(一个块)。要实现这一点，参与者必须能够将组识别为某些已知的数字字符串。例如，埃里克森和他的同事研究的一个人，在编写代码块的过程中使用了来自体育运动历史的关于比赛时间的广泛知识: 几个这样的代码块可以组合成一个更高级的代码块，形成一个代码块的层次结构。这样，只有层次结构最高级别的一些块必须保留在工作内存中，并且为了检索这些块是解压缩的。也就是说，工作记忆中的记忆块作为提取线索，指向它们所包含的数字。根据 Ericsson 和 Kintsch (1995; 参见 Gobet & Simon，2000)的说法，练习这样的记忆技能并不能正确地扩展工作记忆容量: 它是从长期记忆中传递(和检索)信息的能力得到了提高。

大多数成年人能够正确地重复大约7个数字，但有些个体显示出显著增加的数字记忆规模——高达80个数字。这种技术可以通过对编码策略的广泛训练来实现。按编码策略将列表中的数字分组(通常分3到5组) 并将这些组编码为一个独立单元(一个组块)。要实现这一点，参与者必须能够将组块识别为某些已知的数字字符串。例如，埃里克森 Ericsson 和他的同事研究的一位研究对象利用了体育历史中比赛时间的广泛知识来编写代码组块: 几个这样的组块可组合成一个更高级的组块，形成组块层次结构。如此，必须保持在工作记忆中的只有层次结构最高级别的一些组块，且这些组块是打开的用于检索。也就是说，工作记忆中的组块作为提取线索发挥作用，提取它们所指向的数字内容。埃里克森 Ericsson 和 金茨 Kintsch (1995; 参见 Gobet & Simon，2000)认为，练习这种记忆技术并不能真正提高工作记忆容量，所提高的是从长期记忆中传递(和检索)信息的容量。

 

Working memory capacity can be tested by a variety of tasks. A commonly used measure is a dual-task paradigm, combining a memory span measure with a concurrent processing task, sometimes referred to as "complex span". Daneman and Carpenter invented the first version of this kind of task, the "reading span", in 1980. Subjects read a number of sentences (usually between two and six) and tried to remember the last word of each sentence. At the end of the list of sentences, they repeated back the words in their correct order. Other tasks that do not have this dual-task nature have also been shown to be good measures of working memory capacity. Whereas Daneman and Carpenter believed that the combination of "storage" (maintenance) and processing is needed to measure working memory capacity, we know now that the capacity of working memory can be measured with short-term memory tasks that have no additional processing component. Conversely, working memory capacity can also be measured with certain processing tasks that don't involve maintenance of information. The question of what features a task must have to qualify as a good measure of working memory capacity is a topic of ongoing research.

Working memory capacity can be tested by a variety of tasks. A commonly used measure is a dual-task paradigm, combining a memory span measure with a concurrent processing task, sometimes referred to as "complex span". Daneman and Carpenter invented the first version of this kind of task, the "reading span", in 1980. Subjects read a number of sentences (usually between two and six) and tried to remember the last word of each sentence. At the end of the list of sentences, they repeated back the words in their correct order. Other tasks that do not have this dual-task nature have also been shown to be good measures of working memory capacity. Whereas Daneman and Carpenter believed that the combination of "storage" (maintenance) and processing is needed to measure working memory capacity, we know now that the capacity of working memory can be measured with short-term memory tasks that have no additional processing component. Conversely, working memory capacity can also be measured with certain processing tasks that don't involve maintenance of information. The question of what features a task must have to qualify as a good measure of working memory capacity is a topic of ongoing research.

Measures of working-memory capacity are strongly related to performance in other complex cognitive tasks, such as reading comprehension, problem solving, and with measures of intelligence quotient.

Measures of working-memory capacity are strongly related to performance in other complex cognitive tasks, such as reading comprehension, problem solving, and with measures of intelligence quotient.

Some researchers have argued that working-memory capacity reflects the efficiency of executive functions, most notably the ability to maintain multiple task-relevant representations in the face of distracting irrelevant information; and that such tasks seem to reflect individual differences in the ability to focus and maintain attention, particularly when other events are serving to capture attention. Both working memory and executive functions rely strongly, though not exclusively, on frontal brain areas.

Some researchers have argued that working-memory capacity reflects the efficiency of executive functions, most notably the ability to maintain multiple task-relevant representations in the face of distracting irrelevant information; and that such tasks seem to reflect individual differences in the ability to focus and maintain attention, particularly when other events are serving to capture attention. Both working memory and executive functions rely strongly, though not exclusively, on frontal brain areas.

一些研究人员认为，工作记忆容量反映了执行功能的效率，最明显的是面对分散注意力的不相关信息时保持多个任务相关表征的能力; 这些任务似乎反映了集中注意力和保持注意力能力的个体差异，特别是当其他事件有助于吸引注意力时。工作记忆和执行功能都强烈依赖额叶大脑区域，尽管并非完全如此。

一些研究人员主张，工作记忆容量反映执行功能效率，其中在面对分散注意力的不相关信息时维持多个任务相关表征的能力最具代表性; 且这样的任务似乎也反映出个体在集中注意力和保持注意力方面的能力差异，特别是当其他事件在吸引注意力时。工作记忆和执行功能都非常依赖（但不限于）额叶大脑区域。

 

Other researchers have argued that the capacity of working memory is better characterized as the ability to mentally form relations between elements, or to grasp relations in given information. This idea has been advanced, among others, by Graeme Halford, who illustrated it by our limited ability to understand statistical interactions between variables. These authors asked people to compare written statements about the relations between several variables to graphs illustrating the same or a different relation, as in the following sentence: "If the cake is from France, then it has more sugar if it is made with chocolate than if it is made with cream, but if the cake is from Italy, then it has more sugar if it is made with cream than if it is made of chocolate". This statement describes a relation between three variables (country, ingredient, and amount of sugar), which is the maximum most individuals can understand. The capacity limit apparent here is obviously not a memory limit (all relevant information can be seen continuously) but a limit to how many relationships are discerned simultaneously.

Other researchers have argued that the capacity of working memory is better characterized as the ability to mentally form relations between elements, or to grasp relations in given information. This idea has been advanced, among others, by Graeme Halford, who illustrated it by our limited ability to understand statistical interactions between variables. These authors asked people to compare written statements about the relations between several variables to graphs illustrating the same or a different relation, as in the following sentence: "If the cake is from France, then it has more sugar if it is made with chocolate than if it is made with cream, but if the cake is from Italy, then it has more sugar if it is made with cream than if it is made of chocolate". This statement describes a relation between three variables (country, ingredient, and amount of sugar), which is the maximum most individuals can understand. The capacity limit apparent here is obviously not a memory limit (all relevant information can be seen continuously) but a limit to how many relationships are discerned simultaneously.

其他研究人员认为，工作记忆的能力更好的特征是在心理上形成元素之间的关系，或者在给定的信息中抓住关系。这个想法是由格雷姆 · 哈尔福德提出的，他用我们有限的能力来理解变量之间的统计交互作用来说明这一点。这些作者要求人们将关于几个变量之间关系的书面陈述与说明相同或不同关系的图表进行比较，例如下面这句话: ”如果蛋糕来自法国，那么用巧克力做的比用奶油做的含糖量高，但如果蛋糕来自意大利，那么用奶油做的比用巧克力做的含糖量高”。这个陈述描述了三个变量之间的关系(国家、成分和糖的数量) ，这是大多数人能够理解的最大值。这里显而易见的容量限制显然不是内存限制(所有相关信息都可以连续地看到) ，而是同时识别多少关系的限制。

其他研究人员主张，用心理上形成或抓取元素间关系的能力来描述工作记忆容量更佳。Graeme Halford 格雷姆 · 哈尔福德在用我们理解变量之间统计交互作用的有限能力时形成并提出了这个想法。这些发起人要求人们把关于几个变量之间关系的书面陈述与相应的图示（说明相同或不同关系）进行比较，例如: ”如果蛋糕来自法国，那么用巧克力做的比用奶油做的含糖量高，但如果蛋糕来自意大利，那么用奶油做的比用巧克力做的含糖量高”。这个陈述描述了三个变量之间的关系(国家、成分和糖量) ，这是大多数人能够理解的最大值。这里的容量限制显然不是记忆量限制(所有相关信息都可连续看到) ，而是同时识别关系量的限制。

 

There are several hypotheses about the nature of the capacity limit. One is that a limited pool of cognitive resources is needed to keep representations active and thereby available for processing, and for carrying out processes. Another hypothesis is that memory traces in working memory decay within a few seconds, unless refreshed through rehearsal, and because the speed of rehearsal is limited, we can maintain only a limited amount of information. Yet another idea is that representations held in working memory interfere with each other.

There are several hypotheses about the nature of the capacity limit. One is that a limited pool of cognitive resources is needed to keep representations active and thereby available for processing, and for carrying out processes. Another hypothesis is that memory traces in working memory decay within a few seconds, unless refreshed through rehearsal, and because the speed of rehearsal is limited, we can maintain only a limited amount of information. Yet another idea is that representations held in working memory interfere with each other.

The assumption that the contents of short-term or working memory decay over time, unless decay is prevented by rehearsal, goes back to the early days of experimental research on short-term memory. It is also an important assumption in the multi-component theory of working memory. The most elaborate decay-based theory of working memory to date is the "time-based resource sharing model". This theory assumes that representations in working memory decay unless they are refreshed. Refreshing them requires an attentional mechanism that is also needed for any concurrent processing task. When there are small time intervals in which the processing task does not require attention, this time can be used to refresh memory traces. The theory therefore predicts that the amount of forgetting depends on the temporal density of attentional demands of the processing task—this density is called "cognitive load". The cognitive load depends on two variables, the rate at which the processing task requires individual steps to be carried out, and the duration of each step. For example, if the processing task consists of adding digits, then having to add another digit every half second places a higher cognitive load on the system than having to add another digit every two seconds. In a series of experiments, Barrouillet and colleagues have shown that memory for lists of letters depends neither on the number of processing steps nor the total time of processing but on cognitive load.

The assumption that the contents of short-term or working memory decay over time, unless decay is prevented by rehearsal, goes back to the early days of experimental research on short-term memory. It is also an important assumption in the multi-component theory of working memory. The most elaborate decay-based theory of working memory to date is the "time-based resource sharing model". This theory assumes that representations in working memory decay unless they are refreshed. Refreshing them requires an attentional mechanism that is also needed for any concurrent processing task. When there are small time intervals in which the processing task does not require attention, this time can be used to refresh memory traces. The theory therefore predicts that the amount of forgetting depends on the temporal density of attentional demands of the processing task—this density is called "cognitive load". The cognitive load depends on two variables, the rate at which the processing task requires individual steps to be carried out, and the duration of each step. For example, if the processing task consists of adding digits, then having to add another digit every half second places a higher cognitive load on the system than having to add another digit every two seconds. In a series of experiments, Barrouillet and colleagues have shown that memory for lists of letters depends neither on the number of processing steps nor the total time of processing but on cognitive load.

 

Resource theories assume that the capacity of working memory is a limited resource that must be shared between all representations that need to be maintained in working memory simultaneously. Some resource theorists also assume that maintenance and concurrent processing share the same resource;

Resource theories assume that the capacity of working memory is a limited resource that must be shared between all representations that need to be maintained in working memory simultaneously. Some resource theorists also assume that maintenance and concurrent processing share the same resource;

资源理论认为工作记忆容量是一种有限的资源，必须在所有需要同时保存在工作记忆中的表征之间共享。一些资源理论家也假设维护和并发处理共享相同的资源;

资源理论认为工作记忆容量是一种有限的资源，这种资源被所有需要同时保存在工作记忆中的表征共享。一些资源理论学者假设维护和并行处理也占用同样的资源;

 

==== Interference theories====

==== 干涉理论 Interference theories====

Several forms of interference have been discussed by theorists. One of the oldest ideas is that new items simply replace older ones in working memory. Another form of interference is retrieval competition. For example, when the task is to remember a list of 7 words in their order, we need to start recall with the first word. While trying to retrieve the first word, the second word, which is represented in proximity, is accidentally retrieved as well, and the two compete for being recalled. Errors in serial recall tasks are often confusions of neighboring items on a memory list (so-called transpositions), showing that retrieval competition plays a role in limiting our ability to recall lists in order, and probably also in other working memory tasks. A third form of interference is the distortion of representations by superposition: When multiple representations are added on top of each other, each of them is blurred by the presence of all the others. A fourth form of interference assumed by some authors is feature overwriting. The idea is that each word, digit, or other item in working memory is represented as a bundle of features, and when two items share some features, one of them steals the features from the other. The more items are held in working memory, and the more their features overlap, the more each of them will be degraded by the loss of some features.

Several forms of interference have been discussed by theorists. One of the oldest ideas is that new items simply replace older ones in working memory. Another form of interference is retrieval competition. For example, when the task is to remember a list of 7 words in their order, we need to start recall with the first word. While trying to retrieve the first word, the second word, which is represented in proximity, is accidentally retrieved as well, and the two compete for being recalled. Errors in serial recall tasks are often confusions of neighboring items on a memory list (so-called transpositions), showing that retrieval competition plays a role in limiting our ability to recall lists in order, and probably also in other working memory tasks. A third form of interference is the distortion of representations by superposition: When multiple representations are added on top of each other, each of them is blurred by the presence of all the others. A fourth form of interference assumed by some authors is feature overwriting. The idea is that each word, digit, or other item in working memory is represented as a bundle of features, and when two items share some features, one of them steals the features from the other. The more items are held in working memory, and the more their features overlap, the more each of them will be degraded by the loss of some features.

理论家们讨论过几种形式的干涉。最古老的观点之一是，新的事物只是简单地取代了工作记忆中旧的事物。另一种形式的干扰是检索竞赛。例如，当任务是按顺序记住7个单词时，我们需要从第一个单词开始回忆。在试图检索第一个单词时，第二个单词也会意外地被检索到，这两个单词会争着被回忆起来。连续回忆任务中的错误通常是记忆列表中相邻项目的混淆(即所谓的换位) ，这表明提取竞争限制了我们按顺序回忆列表的能力，可能在其他工作记忆任务中也是如此。第三种形式的干涉是叠加对表象的扭曲: 当多重表象叠加在一起时，每一种表象都会因为所有其他表象的存在而模糊不清。一些作者认为的第四种干扰形式是特征覆盖。这个想法是，工作记忆中的每个单词、数字或其他项目都被表示为一系列特征，当两个项目共享某些特征时，其中一个就会窃取另一个的特征。工作记忆中保存的条目越多，它们之间的特征重叠越多，每个条目由于某些特征的丢失而降低的程度就越大。

理论家们讨论过几种形式的干涉。最初的观点之一是，新事物只是单纯地取代了工作记忆中的旧事物。另一种干涉形式是检索竞争。例如当任务是顺序记住7个单词时，需要从第一个单词开始回忆，而在试图检索第一个单词时，第二个单词也会意外地被检索到，而这两个单词会竞争忆起。连续回忆任务中的错误通常是记忆列表中相邻项目的混淆(即所谓的换位) ，这表明检索竞争限制了我们顺序回忆列表的能力，在其他工作记忆任务中也可能有这种限制。第三种形式的干涉是叠表征的变形: 当多重表征叠加在一起时，每一表征都因所有其他表征而模糊不清。一些发起人认为的第四种干涉形式是特征覆盖。该观点认为工作记忆中的每个单词、数字或其他项目都被表示为一系列特征，当两个项目共享某些特征时，其中一个就会窃取另一个的特征。工作记忆中保存的条目越多则重叠的特征越多，每个条目由于其某些特征丢失而减损越多。

 

这些假说都不能完全解释实验数据。例如，资源假说旨在解释维护和加工之间的权衡: 工作记忆中必须保存的信息越多，并发过程就变得越慢、越容易出错，同时对并发加工记忆的要求也越高。这种权衡已经通过上面描述的阅读跨度任务等任务进行了研究。研究发现，权衡的数量取决于要记忆的信息和要处理的信息的相似性。例如，在处理空间信息时记忆数字，或者在处理数字时记忆空间信息，这些都比同类材料必须记忆和处理时相互影响小得多。此外，记忆单词和处理数字，或者记忆数字和处理单词，比记忆和处理同一类别的材料更容易。这些发现对于衰退假说也很难解释，因为记忆表征的衰退只取决于加工任务延迟复述或回忆的时间，而不取决于加工任务的内容。衰退假说的另一个问题来自于延迟回忆一个字母列表的实验，要么是指示参与者以较慢的速度回忆，要么是指示他们在回忆每个字母之间说一个不相关的单词一次或三次。延迟回忆对回忆准确率几乎没有影响。干扰理论似乎最好地解释了为什么内存内容和同时处理的任务内容之间的相似性会影响它们彼此之间的损害程度。越多的相似材料越容易混淆，导致检索竞争。

这些假说都不能完全解释实验数据。例如，资源假说旨在解释维护和加工之间的权衡: 工作记忆中必须保存的信息越多，并发过程就变得越慢、越容易出错，同时对并发加工记忆的要求也越高。这种权衡已经通过上面描述的阅读跨度任务等任务进行了研究。研究发现，权衡的数量取决于要记忆的信息和要处理的信息的相似性。例如，在处理空间信息时记忆数字，或者在处理数字时记忆空间信息，这些都比同类材料必须记忆和处理时相互影响小得多。此外，记忆单词和处理数字，或者记忆数字和处理单词，比记忆和处理同一类别的材料更容易。这些发现对于衰退假说也很难解释，因为记忆表征的衰退只取决于加工任务延迟复述或回忆的时间，而不取决于加工任务的内容。衰退假说的另一个问题来自于延迟回忆一个字母列表的实验，要么是指示参与者以较慢的速度回忆，要么是指示他们在回忆每个字母之间说一个不相关的单词一次或三次。延迟回忆对回忆准确率几乎没有影响。干扰理论似乎最好地解释了为什么内存内容和同时处理的任务内容之间的相似性会影响它们彼此之间的损害程度。越多的相似材料越容易混淆，导致检索竞争。

== 发展 Development ==

== 发展 Development ==