Which WM component is most engaged when performing a backward digit span task that requires mental manipulation of information?

• A. Phonological Loop
• B. Episodic Buffer
• C. Central Executive
• D. Visuo-Spatial Sketchpad

Answer: (C)

Backward digit span involves more than just keeping a sequence in mind; you must actively transform it by reversing the order. That kind of mental manipulation is the job of the Central Executive, the control system that directs attention, updates and manipulates information, and coordinates cognitive operations. It handles planning, switching tasks, and inhibiting automatic responses, which are all needed to reorder the digits.

The Phonological Loop would handle the verbal rehearsal of the digits, keeping them in phonological form, but it doesn’t perform the reversal itself. The Visuo-Spatial Sketchpad deals with visual or spatial information, which isn’t central here since the task is verbal. The Episodic Buffer could help integrate information across modalities or link it into a broader memory episode, but the key requirement of the task—manipulating the order—primarily hinges on the Central Executive.