In psychology and neuroscience, memory span is the longest list of items that a person can repeat back in correct order immediately after presentation on 50% of all trials.
Backward memory span is a more challenging variation which involves recalling items in reverse order.
To generalize, it refers to the ability of an individual to reproduce immediately, after one presentation, a series of discrete stimuli in their original order.
[1] Experiments in memory span have found that the more familiar a person is with the type of subject matter presented to them, the more they will remember it in a novel setting.
[2] According to a theory by Alan Baddeley and Graham Hitch, working memory is under the influence of three key mechanisms: the visuospatial sketchpad, the central executive, and the phonological loop.
[2]Verbal working memory is involved in many everyday tasks, such as remembering a friend's telephone number while entering it into a phone and understanding long and difficult sentences.
[9][citation needed] Verbal working memory is also thought to be one of the elements underlying intelligence (often referred to as IQ, meaning 'intelligence quotient'); thus, the digit span task is a common component of many IQ tests, including the widely used Wechsler Adult Intelligence Scale (WAIS).
Though numerous factors affect memory span, the test is one that shows surprisingly high reliability.
Results obtained by different investigators show that the reliability coefficients for memory span are quite high.
[citation needed] There are certain intrinsic factors specific to each individual that may affect the extent, or span, of one's working memory.
One of the key aspects of working memory is the ability to inhibit distractions and to focus on stimulus cues.
[25][26] Preschoolers given short-term musical training showed improvement in their executive function and verbal memory span.
[31] In a typical test of memory span, a list of random numbers or letters is read out loud or presented on a computer screen at the rate of one per second.
When Daneman and Carpenter investigated this method in 1980, they found a strong correlation between the number of words memorized and the comprehension performance for the processing questions.
In complex span tasks encoding of the memory items (e.g., words) alternates with brief processing episodes (e.g., reading sentences).
[38] Complex-span tasks have also been shown to be closely related to many other aspects of complex cognitive performance besides language comprehension, among other things to measures of fluid intelligence.
[39][40] There is the possibility that susceptibility to proactive interference (PI) affects performance on memory span measures.
Indeed, other studies show that individual differences in susceptibility to PI are predictive of scores on standard achievement tests.