Digit-span
Digit-span task is used to measure working memory's number storage capacity. Participants are presented with a series of digits (e.g., '8, 3, 4') and must immediately repeat them back. If they do this successfully, they are given a longer list (e.g., '9, 2, 4, 0'). The length of the longest list a person can remember is that person's digit span. While the participant is asked to enter the digits in the given order in the forward digit-span task, in the backward digit-span task the participant needs to reverse the order of the numbers.
| Memory span | |
|---|---|
| Diagnostics | |
This is a graphical representation of typical results that might be obtained from performing a forward/backward digit span recall task on participants in several different age groups. The numbers on the y-axis indicate number of digits successfully recalled. |
|
| MeSH | D011581 |
The digit span task exercises verbal working memory. Scientists refer to working memory as the cognitive system that allows the temporary storage and manipulation of information. According to one influential cognitive theory, this system has specialised components, one of which, the 'Phonological loop', underlies verbal working memory abilities (Baddeley & Hitch 1974). The phonological loop consists of a verbal storage system and a rehearsal system. Participants may find themselves mentally rehearsing the string of digits as they appear on screen; this is the rehearsal system in action. It allows the visual inputs to be recoded so that they can enter short term verbal store and it also refreshes decaying representations (that is, any item that is about to be forgotten).
Verbal working memory is involved in many everyday tasks, from remembering a friend's telephone number while entering it into a phone, to understanding long and difficult sentences. For example, it is difficult to understand a whole sentence without remembering the words at the beginning long enough to connect them with the words at the end. 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). Performance on the digit span task is also closely linked to language learning abilities; improving verbal memory capacities may therefore aid mastery of a new language.
Read more about this topic: Memory Span