title: Enhancing a tone by shifting its frequency or intensity.
abstract: When a test sound consisting of pure tones with equal intensities is preceded by a precursor sound identical to the test sound except for a reduction in the intensity of one tone, an auditory "enhancement" phenomenon occurs: In the test sound, the tone which was previously softer stands out perceptually. Here, enhancement was investigated using inharmonic sounds made up of five pure tones well resolved in the auditory periphery. It was found that enhancement can be elicited not only by increases in intensity but also by shifts in frequency. In both cases, when the precursor and test sounds are separated by a 500-ms delay, inserting a burst of pink noise during the delay has little effect on enhancement. Presenting the precursor and test sounds to opposite ears rather than to the same ear significantly reduces the enhancement resulting from increases in intensity, but not the enhancement resulting from shifts in frequency. This difference suggests that the mechanisms of enhancement are not identical for the two types of change. For frequency shifts, enhancement may be partly based on the existence of automatic "frequency-shift detectors" [Demany and Ramos, J. Acoust. Soc. Am. 117, 833-841 (2005)].
authors.affiliation: Institut de Neurosciences Cognitives et Intégratives d'Aquitaine (UMR CNRS 5287), BP 63, Université de Bordeaux, 146 rue Leo Saignat, F-33076 Bordeaux, France.
authors.forename: Mayalen
authors.initials: M
authors.lastname: Erviti
authors.forename: Catherine
authors.initials: C
authors.lastname: Semal
authors.forename: Laurent
authors.initials: L
authors.lastname: Demany
mesh_terms: D000161:Acoustic Stimulation; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009622:Noise; D010898:Pitch Perception; D013997:Time Factors; D055815:Young Adult