Importance of pitch and spatial separation for the Cocktail party effect

This study examines two important factors for the conception Auditory Streaming defined by Bregman, pitch and localization. By removing one or two of these factors as possible identifiers to separate sound sources, the importance of each of them and the combined effect of reducing both of them will be studied. Stimuli with combinations of two-syllable words were presented simultaneously in speakers to subjects and the number of correct identifications was measured. In one category of stimuli speech melody was removed and replaced with a monotonous pitch, equal for all words. One category had all words presented from one speaker only. Significant effect regarding the success of identification was found for both investigated factors as well as for interaction them in between. The study shows that removal of differences in pitch or spatial origin between voices lessens our ability to identify the word content. The results go well in line with earlier studies and common theories, the Cocktail party effect among others.Validerat; 20111115 (anonymous