Memory span testing

Definition of Memory

Memory refers to the psychological processes of acquiring, storing, retaining, and later retrieving information. There are three major processes involved in memory: encoding, storage, and retrieval.

Span of Memory 

Memory span may be defined functionally as "the ability of an individual to reproduce immediately, after one presentation, a series of discrete stimuli in their original order."

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. Items may include words, numbers, or letters. The task is known as digit span when numbers are used.

Factors 

Memory span involves processes of attention, associability, imagery, and memory. Variation in memory span with material and sense organ may result from inaccuracies in methods used to study a general ability or from specificity of memory span. Memory span is influenced by extrinsic factors (characteristics of the material used, rhythm of presentation, rate of presentation, method of scoring the responses, fatigue, time of day, attitude, distraction, practice, subjective grouping of the units, temporary pathological condition, effect of drugs) and intrinsic factors (age, sex, race, permanent pathological condition). Extrinsic factors can be controlled carefully enough for memory span tests to show high reliability. The relation between memory span and intelligence has led to its use as a clinical test.

Memory span test

A. Forward test : 

Digit Span Forward requires the subject to repeat numbers in the same order as read aloud by the examiner.Digit span forward is a good measure of simple attention, and most healthy individuals perform within the seven plus/minus two span of apprehension range.

B. Backward test:

Digit Span Backward requires the child to repeat the numbers in the reverse order of that presented by the examiner. Digit Span backwards represents a qualitatively different type of task that relies more upon working memory skills that should be considered separately from digits forward .

Memory and Brain

Prefrontal cortex is involved in short term memory. The prefrontal cortex (PFC) plays a central role in cognitive control functions. The temporal lobe is associated with episodic and long term semantic memory.

References

Blankenship, A. B. (1938). Memory span: a review of the literature. Psychological Bulletin, 35(1), 1–25. https://doi.org/10.1037/h0061086.

Miller, G.A. (1956). The magical number seven plus or minus two. Some limits on our capacity for processing information. Psychological Review, 63, 81-97.

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Memory span refers to the number of items (usually words or digits) that a person can hold in working memory. Tests of memory span are often used to measure working memory capacity. A typical test of memory span involves having an examiner read a list of random digits (digit span) or words (word span) aloud at the rate of one per second. At the end of a sequence, subjects are asked to recall the items in order. The average span for normal adults is 7.

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