Which of the following is a subset of working memory on IQ tests?

• A. Coding
• B. Symbol Search
• C. Cancellation
• D. Digit Span

Answer: (D)

Working memory is the ability to hold information in mind and actively work with it to complete a task. In the digit span task, you hear a sequence of numbers and must repeat them back in a specified way. Repeating in the same order tests maintaining a sequence in mind, but repeating in reverse or in a reordered sequence requires you to manipulate the items mentally. That combination of holding information and actively transforming it is what characterizes working memory.

Because digit span directly taps both holding and manipulating information, it’s considered a measure of working memory on IQ tests. The other tasks focus more on speed and automatic processing of visual or symbolic information—coding and symbol search assess processing speed and perceptual speed, while cancellation emphasizes attention and rapid visual search—so they don’t target the working memory component in the same way.