Auditory Sensitivity of the Goldfish within the near Acoustic Field

Four experiments were conducted on auditory sensitivity and discrimination of goldfish within the acoustic near field. Experiment I studied the effects of the near field on sound pressure thresholds. The sensitivity of goldfish in terms of sound pressure appeared to vary with distance from the sound source. Experiment II studied stimulus generalization and frequency discrimination within the near field. A generalization gradient was observed which indicated that goldfish can discriminate a frequency change as small as 12.5% without explicit differential training. Experiment III studied the effects of far field noise or near field thresholds. A masking effect was observed which appeared to be a negatively accelerated function of masker spectrum level. Experiment IV tested the ability of goldfish to localize a sound source within the near field. It was shown that goldfish could discriminate between right 45° and left 45° stimulus directions. Discussion is presented concerning the implications of the results of the four experiments and their relevance to the study of underwater communication. AUDITORY SENSITIVITY OF THE GOLDFISH WITHIN THE NEAR ACOUSTIC FIELD