How do irrelevant speech and articulatory suppression differ in their effects on working memory tasks?

• A. They are the same mechanism.
• B. Irrelevant speech is external background speech that disrupts recall; articulatory suppression is covert repetition that reduces rehearsal.
• C. Irrelevant speech improves recall.
• D. Articulatory suppression uses external speech to aid rehearsal.

Answer: (B)

The key idea is how the phonological loop in working memory can be disrupted by two different mechanisms: external background speech versus an internal suppression of rehearsal. In Baddeley’s model, the phonological loop has a phonological store for holding sounds and an articulatory rehearsal process that refreshes those items.

Irrelevant speech is external background speech that competes with the to-be-remembered material for the phonological store. Because the store codes sounds, hearing background speech interferes with the encoding and maintenance of the sequence you’re trying to recall, making serial recall harder.

Articulatory suppression, on the other hand, involves covertly repeating something (like saying a syllable out loud in your head) to occupy the articulatory rehearsal process. This use of the rehearsal mechanism prevents you from refreshing the memory traces of the items, so they decay or are not reinforced, leading to poorer recall.

So they differ in where the disruption happens: one is external interference that disrupts the store's contents, the other is internal interference that blocks the rehearsal process. Both impair performance on verbal working-memory tasks, but not by the same mechanism.