Irrelevant Speech Effect

The irrelevant speech effect, also called the irrelevant sound effect, is the finding that background sound, especially speech, degrades a person's ability to recall a list of items in the order they were presented, even when the list itself is shown visually rather than spoken aloud. The interfering sound does not need to be in a language the listener understands, or even be actual language at all; the effect appears as long as the background sound carries the acoustic properties of human speech. The leading explanation, the interference or phonological-loop account, holds that people store a visually presented list in working memory using phonological codes maintained by an articulatory rehearsal process, and background speech disrupts that rehearsal, degrading the stored information and impairing recall, an effect that falls hardest on items rehearsed the longest, meaning those presented earliest in the list. Researchers including Perham and Vizard in 2010 and Longoni, Richardson and Aiello in 1993 have documented this interference experimentally, and the theory extends beyond speech to cover music and other background sounds as well.