Irrelevant Speech Effect
The degradation of serial recall when speech sounds are presented, even if the list items are presented visually. The sounds need not be a language the participant understands, nor even a real language; human speech sounds are sufficient to produce this effect.
Origin
In 1976, psychologists H.A. Colle and A. Welsh published in the Journal of Verbal Learning and Verbal Behavior that background speech impairs a person's ability to recall a sequence of items in order — even when the speech is in an unknown language and the listener is told to ignore it. The finding challenged prevailing models of working memory, specifically Baddeley's phonological loop, which researchers initially used to explain the interference. The research revealed that auditory processing competes for the same cognitive resources used to encode sequential order in short-term memory, regardless of the listener's intent.