| Abstract: | Seven parakeets were trained to avoid shock during pure-tone stimulation. A modified method of limits was used to measure detection thresholds of the pure tones. The intensity of masker tones, at numerous frequencies, was varied to measure the masked threshold of a probe-tone signal set at a fixed frequency and intensity. Masking curves were obtained for 3 probe tones (.63, 1.6, and 2.5 kHz) at each of 5 sensation levels (10, 20, 30, 40, and 50 db). The masking curves from this procedure, which are frequently referred to as "psychophysical tuning curves," provide an indication of frequency selectivity. Results are compared with analogous data in other species and suggest that frequency analysis in the parakeet ear is somewhat less accurate than in the mammalian ear. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
