Date of Award

2013

Document Type

Thesis

Degree Name

Bachelors

Department

Social Sciences

First Advisor

Harley, Heidi

Keywords

Dolphin, Echolocation, Comparative Cognition

Area of Concentration

Psychology

Abstract

Dolphins use echolocation to discriminate amongst stimuli within their environment. Echolocation provides a unique way to learn about object recognition strategies because it is active (i.e., the dolphin produces clicks to gain information about objects). A few studies show that dolphins adapt their echolocation across contexts, but the characteristics that motivate these adaptations are not clear. The present study examines how an Atlantic bottlenose dolphin's (Tursiops truncatus) echoic investigation of stimuli changes across an object recognition task as initially novel objects become familiar and as performance accuracy increases. Acoustical and video recordings were obtained during a three-alternative matching-to-sample task in which a blind-folded dolphin examined a sample object and selected the matching object from three alternatives. Analysis of the investigation of the sample object determined the number of clicks emitted, time spent echolocating the sample, number of echolocation trains, and occurrence of a terminal burst pulse. Results showed that number of clicks and time spent echolocating decreased when familiar objects were more easily recognized (i.e., performance accuracy was high), suggesting that dolphins become faster and more efficient at echoic processing when objects are easily identified. Though there was low variability in the number of echolocation trains, the time between echolocation trains may be important to processing previous echoes. The frequent occurrence of the terminal burst pulse suggests that this vocalization may function in some way during object recognition. Results also showed that echoic effort stayed high when objects were difficult to identify, suggesting that the dolphin was putting in extra effort in order to try and solve the task. These data could inform training by the US Navy of bottlenose dolphins that recover and locate objects: because echoic efficiency increases with familiar, easily discriminated objects, the training program should include experience with targets of interest.

Rights

The author has granted New College of Florida the nonexclusive right to archive, make accessible, and distribute for educational purposes this work in whole or in part in all forms of media, now or hereafter known. The copyright of this work remains with the author.

Download

Share

COinS