<P> The cocktail party effect is the phenomenon of the brain's ability to focus one's auditory attention (an effect of selective attention in the brain) on a particular stimulus while filtering out a range of other stimuli, 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 . Thus, it has been proposed that one's sensory memory subconsciously siphons through all stimuli, and when an important word or phrase with high meaning appears, it stands out to the listener . This effect is what allows most people to "tune into" a single voice and "tune out" all others . 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 in another conversation during a cocktail party . </P> <P> Auditory attention in regards to the cocktail party effect primarily occurs in the left hemisphere of the superior temporal gyrus (where the primary 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 shows that target streams are treated with more attention than competing streams . </P>

The ability to focus on one voice and tune out other voices involves