title: Frequency difference limens at high frequencies: evidence for a transition from a temporal to a place code.
abstract: It is commonly believed that difference limens for frequency (DLFs) for pure tones depend on a temporal mechanism (phase locking) for frequencies up to 4-5 kHz and a place mechanism at higher frequencies. The DLFs predicted from a place mechanism, expressed as a proportion of center frequency (Δf/f), should be approximately invariant with frequency at medium to high frequencies. If there is a transition from a temporal to a place mechanism, Δf/f should increase with increasing center frequency until the transition occurs, and then reach a plateau. Published data do not show such an effect. In this study, DLFs were measured for center frequencies from 2 to 14 kHz, using earphones designed to produce a flat response at the eardrum. The level of every tone was varied over a range of ±4 dB, to reduce loudness cues. The value of Δf/f increased progressively from 2 to 8 kHz, but did not change significantly for frequencies from 8 to 14 kHz. The results are consistent with the idea that there is a transition from a temporal to a place mechanism at about 8 kHz, rather than at 4-5 kHz, as is commonly assumed.
authors.affiliation: Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, United Kingdom. bcjm@cam.ac.uk
authors.forename: Brian C J
authors.initials: BC
authors.lastname: Moore
authors.forename: Stephan M A
authors.initials: SM
authors.lastname: Ernst
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001301:Audiometry, Pure-Tone; D001306:Auditory Pathways / Q000502:physiology*; D001309:Auditory Threshold; D003463:Cues; D005260:Female; D006801:Humans; D008144:Loudness Perception; D008297:Male; D010897:Pitch Discrimination; D010898:Pitch Perception; D013997:Time Factors; D055815:Young Adult