Dolphin Auditory Discrimination Training: Dolphin Vocalizations Versus Synthesized Pure Tones
   

Douglas Cross, Ph.D.
Department of Speech Pathology and Audiology
Ithaca College, Ithaca, NY 14850
cross@ithaca.edu

This page presents sample images and initial behavior training data as dolphins "Bob" and "Christie" learned a basic auditory discrimination task for the first time. They learned an experimental task in which they discriminated between pure tones and prerecorded dolphin whistle vocalizations presented underwater. This initial training was part one of a larger project designed to study hemispheric specialization for auditory perception in the Atlantic bottlenose dolphin. The study took place at "The Living Seas" pavilion of the Epcot Center in Orlando, Florida.

First, the dolphin subjects were trained to "station" 1 meter in front of an underwater microphone (hydrophone) and wait for presentation of prerecorded auditory signals. From there, the dolphins were trained to identify whether the underwater stimulus was a prerecorded 1 kHz pure tone or a prerecorded dolphin whistle vocalization. The pure tone was matched in duration with the vocalization. They were trained to touch one surface float with their rostrum (nose) if the stimulus was the pure tone and touch a different surface float if it was the dolphin vocalization. Typically, there were two sets of twenty trials in each training session with two training sessions per day and four-five days of training per week. The entire study extended over a ten week period.Neither animal had any previous experience learning a discrimination type procedure.

Both dolphin subjects participated in each of their training sessions voluntarily. That is, either subject could terminate a session merely by not participating. As is the policy at "The Living Seas" No negative coercion of any form used before during or after sessions, regardless of whether they participated in the session or not.

This investigation was supported, in part, by a Faculty Summer Research Grant from Ithaca College.

- Additional Photos -