Memory span
Memory span refers to the maximum number of items that an individual can accurately retain and recall from working memory after a single exposure. This aspect of memory is a crucial indicator of one's working memory capabilities, which play a vital role in various cognitive functions, including learning, information retrieval, and problem-solving. Memory span assessments typically involve tasks such as recalling a list of numbers, letters, or words in the order presented, and can vary in complexity and format. Different types of memory span tests, such as digit span or reading span tests, help researchers explore how various factors influence memory capacity, including the type of items used and the modality of presentation (auditory vs. visual). Historical research suggests that the average memory span for digits is around seven, with variations noted for words and letters. Additionally, factors such as age, physical condition, and the word-articulation effect—where shorter, easily pronounced words lead to improved recall—can impact performance on these tests. Understanding memory span is essential for assessing cognitive changes related to aging, neurological disorders, and learning challenges.
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Memory span
A memory span is the longest series of items a person has an even chance of retaining and recalling from working memory, the part of short-term memory that deals with immediate perceptual and linguistic processing. A simple memory span test might consist of the test administrator reading aloud one number, letter, or word per second from a list of randomly selected items. After listening to the list once, the administrator asks the participant to recite the items in the order that they were listed.
Memory span is an indicator of one’s working memory capabilities. Being able to assess an individual’s working memory is important because it is part of several cognitive functions such as learning, retrieving information from long-term memory, filtering information, and solving new problems. Such assessments can help determine changes in cognitive and intellectual performance related to aging, dementia, developmental disabilities, genetic disorders, learning disabilities, medical conditions, neurological disorders, and psychiatric conditions.
Overview
Different types of memory span tests shed light on different aspects of working memory. For example, a digit span test measures the number storage capacity of a person’s working memory. A running memory span test includes a series of items that ends unpredictably and asks the subject to recall the last few items. Tests can also vary in their level of complexity. A reading span is an example of a complex test. In a backward memory span, the subject is asked to recall items in reverse order, a more difficult task than recalling items in the order they were presented.
One way that tests vary is in the type of items used in the series, or item class. In addition to numbers, letters, syllables, and words, researchers have used a range of auditory and visual items. In 1927, H. Sherman Oberly of the University of Pennsylvania reported that participants in memory span trials could accurately recall a series of seven digits in half of the tests they were given. In 1957, C. W. Crannell and J. M. Parish published their findings that memory span differed depending on the type of items; their participants corroborated Oberly’s findings for a mean span of seven digits, but also found mean spans of five words and six letters, respectively.
Other researchers have found that memory span varies with the modality of the test, or the way in which the information is presented during the assessment. Memory span tends to be longer when participants are presented with a list of auditory items versus visual items.
Researchers have found other factors besides item class and test modality that can influence memory span. In 1975, Alan D. Baddeley, Neil Thomson, and Mary Buchanan presented research on what they called the word-articulation effect on memory span. Through their experiments, they found that memory span increases when tests used words that take less time to pronounce.
Factors such as the word-articulation effect can affect the outcomes of memory span tests, and researchers must be aware of them and account for them in order to get accurate results. While some of these factors are part of the test environment, others, such as the participant’s age and physical condition, are individual.
Bibliography
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