Analysing your IQ
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Test your working memory capacity. Remember and recall number sequences forward and backward to measure your digit span.
Digits will flash on screen one at a time. Remember and type them back.
Forward span: Type the digits in order.
Backward span: Type the digits in reverse order.
The digit span test is one of the oldest and most widely used measures of working memory. First introduced by Jacobs in 1887, it has been a core subtest of the Wechsler Intelligence Scales since their inception. Working memory - the ability to hold and manipulate information temporarily - is fundamental to almost every cognitive task we perform, from mental arithmetic to reading comprehension to following conversations.
The average adult can recall about 7 ± 2 digits forward, a finding famously described by psychologist George Miller in 1956 as "the magical number seven." Forward span primarily measures short-term storage capacity, while backward span adds a manipulation component, requiring you to mentally reverse the sequence. This makes backward span a purer measure of working memory and a stronger predictor of fluid intelligence.
Digit span is a subtest of the Wechsler Adult Intelligence Scale (WAIS-IV), where it contributes to the Working Memory Index. This index, along with Verbal Comprehension, Perceptual Reasoning, and Processing Speed, determines your Full Scale IQ. Working memory has been shown to account for a significant portion of the variance in fluid intelligence, with correlations typically ranging from r = 0.5 to 0.7.
Clinical psychologists also use digit span to assess cognitive impairment. Significant differences between forward and backward spans can indicate specific neurological conditions. For example, patients with frontal lobe damage often show preserved forward span but impaired backward span, reflecting the executive component required for mental manipulation.
The average adult can recall 7 plus or minus 2 digits forward (so 5-9 digits) and about 5 plus or minus 2 digits backward. This range was famously described by psychologist George Miller in 1956 as "the magical number seven."
Digit span measures working memory capacity, which is the ability to hold and manipulate information in your mind. Forward digit span primarily measures short-term memory, while backward digit span also requires mental manipulation and is more strongly correlated with fluid intelligence.
Yes, digit span is a subtest of the Wechsler Adult Intelligence Scale (WAIS), one of the most widely used IQ tests. It contributes to the Working Memory Index. Backward digit span in particular shows moderate correlations (r = 0.4-0.5) with overall IQ scores.
