title: Auditory frequency discrimination in the squirrel monkey.
abstract: Four squirrel monkeys (Saimiri sciureus) were tested for their frequency discrimination capacity using an eyeblink classical conditioning procedure, with air puff against the eye as unconditioned stimulus and 600-ms pure tones as conditioned stimuli. Absolute frequency difference thresholds showed a minimum (20-41 Hz, mean 30 Hz) at 4,000-8,000 Hz and increased towards higher as well as lower frequencies (70-90 Hz, mean 80 Hz at 300 Hz; 44-120 Hz, mean 82 Hz at 16,000 Hz). Relative frequency difference thresholds increased from higher to lower frequencies, with values as low as 0.3-0.8% (mean 0.5%) at 16,000 Hz and as large as 24-30% (mean 27%) at 300 Hz. The squirrel monkey's frequency discrimination function thus shows a severe deviation from Weber's law. The frequency difference thresholds are comparable to human's in the 4,000-8,000 Hz range, but are 65-80 times higher in the 500- to 300-Hz range. Individuals with high auditory thresholds do not necessarily also have high frequency difference thresholds.
authors.affiliation: Neurobiology Department, German Primate Centre, Göttingen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Wienicke
authors.forename: U
authors.initials: U
authors.lastname: Häusler
authors.forename: U
authors.initials: U
authors.lastname: Jürgens
mesh_terms: D000162:Acoustics; D000818:Animals; D001307:Auditory Perception / Q000502:physiology*; D003214:Conditioning, Classical; D004193:Discrimination Learning; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D008297:Male; D012453:Saimiri / Q000502:physiology*