Effet cocktail party

The cocktail party effect is the phenomenon of the brain's ability to focus one's auditory attention on a particular stimulus while filtering out a range of other stimuli, such as when a partygoer can focus on a single conversation in a noisy room. Listeners have the ability to both segregate different stimuli into different streams, and subsequently decide which streams are most pertinent to them. It has been proposed that one's sensory memory subconsciously parses all stimuli and identifies discrete pieces of information by classifying them by salience. This effect is what allows most people to "tune into" a single voice and "tune out" all others. This phenomenon is often described in terms of "selective attention" or "selective hearing". It may also describe a similar phenomenon that occurs when one may immediately detect words of importance originating from unattended stimuli, for instance hearing one's name among a wide range of auditory input. An inability to segregate stimuli in this way is sometimes referred to as the cocktail party problem or cocktail party deafness. Auditory attention in regards to the cocktail party effect primarily occurs in the left hemisphere of the superior temporal gyrus, a non-primary region of auditory cortex; a fronto-parietal network involving the inferior frontal gyrus, superior parietal sulcus, and intraparietal sulcus also accounts for the acts of attention-shifting, speech processing, and attention control. Both the target stream (the more important information being attended to) and competing/interfering streams are processed in the same pathway within the left hemisphere, but fMRI scans show that target streams are treated with more attention than competing streams. Furthermore, activity in the superior temporal gyrus (STG) toward the target stream is decreased/interfered with when competing stimuli streams (that typically hold significant value) arise.