How is digit span used to assess the phonological loop?

• A. It measures nonverbal memory capacity.
• B. It measures verbal short-term memory capacity and reflects storage and rehearsal efficiency; backward span also taps central executive.
• C. It measures long-term memory encoding.
• D. It measures motor sequencing.

Answer: (B)

Digit span tasks use sequences of digits spoken aloud and then repeated back, either in order or in reverse. This directly taps the phonological loop, which handles verbal, auditory information. The key components are the phonological store, where the sounds are held briefly, and the articulatory rehearsal process, which refreshes those items so they don’t fade. So performance on forward digit span reflects how much verbal material can be stored and refreshed—i.e., verbal short-term memory capacity and how efficiently those storage and rehearsal processes operate.

When you do a backward digit span, you introduce a manipulation requirement that goes beyond simple storage. Reversing the sequence uses the central executive to reorganize and transform the information, so this task also draws on that control system in addition to the phonological loop.

Nonverbal memory, long-term memory encoding, or motor sequencing don’t capture this verbal short-term storage and rehearsal mechanism as directly, which is why the digit span approach is best described as assessing the phonological loop’s capacity and efficiency.