Louis Herman is perhaps todays foremost researcher studying communication and cognitive abilities in dolphins through using artificial languages (i.e. simple languages created for the research). He has focused on language comprehension rather than production, because comprehension is the first sign of linguistic competency in young children, and because comprehension can be tested in a more controlled manner than production.
In Herman's work, two dolphins, Akeakamai (Ake), and Phoenix, were taught artificial languages. Phoenix was taught an acoustical language made of computer generated sounds. Ake was taught a gestural, or visual, language. The signals of the artificial languages represent objects, object modifiers, or actions. Neither the gestures nor the sounds resemble the objects or relational terms to which they refer. The languages also use syntax or simple grammar rules, meaning that the word order effects the meaning of the sentence. Phoenix was taught a straightforward left-to-right grammar. Ake's gestural language grammar is inverse, requiring her to view an entire gestured sequence before it can be interpreted correctly. For example, in Ake's gestural language, the sequence of signals PIPE SURFBOARD FETCH means bring the surfboard to the pipe, and SURFBOARD PIPE FETCH means bring the pipe to the surfboard. Phoenix and Ake have each learned approx. 50 words, these 50 words allow more than 1000 different 'sentences', each eliciting an unlearned, unrehearsed response. To minimize any possible effects of orientation to space or person on dolphin learning, stations and trainers are changed from session to session. Blind observers, people who do not know and can not see the commands given, are used to label the actions they observe the dolphins perform as a means of comparing objectively the response to the command.
Trainers wear dark goggles, maintain expressionless faces, and hold their bodies steady during formal training sessions. Dolphins can understand gestural signals given by televised images of signers about as well as they can from live signers. Even just showing white hands in black space, or white spots of light tracing out the dynamics of the gesture, were understood. Because of these experiments, it seems that the dolphins are responding to the abstract symbols of the language rather than to any non-language communication or cues.
In addition to following the language instructions, Herman's dolphins can now correctly answer whether a specified item is present or absent by pressing the appropriate paddle (the white one for yes, or present, and the black one for no, or absent). This demonstrates the skill of displacement, the conjuring of images that are not around. It has been similarly demonstrated by Sue Savage-Rumbaugh, of Yerkes Primate Research Center, that apes are able to understand a reference to something that is not in their presence.
Additional experiments have been conducted to determine how the dolphins are interpreting the language labels. "We did test to see, for example, what a hoop is to a dolphin. A hoop is not just the hoop used in training the animal. It's anything with an opening in it, relatively large to its perimeter. So we have round, square, and little hoops; hoops that float and hoops that lie on the bottom."Footnote5
Things Herman has been unable to successfully teach the dolphins includes the concept "not" as a logical modifier, so that jump over "NOT BALL" would indicate jump over anything but a ball. Also large and small do not seem to have been understood by the dolphins.
Data acquired from whale vocalization studies was practically applied to save a young whale when Herman provided a recorded whale feeding sound that was used to successfully lure Humphrey, the humpback whale who had swam more than fifty miles up the Sacramento river, back to the open ocean.
Says Herman, "We now ask, `Is there a frisbee in the tank?` It's not much of a stretch to say, `Is there a whale out there? A submarine? What's on the bottom?`"Footnote6
